The World of Protozoa, Rotifera, Nematoda and Oligochaeta
Brachionus
Brachionus Pallas, 1766 (ref. ID; 7815)
Class Rotatoria: Order Ploimida: Family Brachionidae (ref. ID; 7097)
Synonym Noteus Ehrenberg, 1830 (ref. ID; 2891, 3688), Schizocerca Daday, 1883 (ref. ID; 3688)
Most confused Platyias.
ref. ID; 953
The structure of the trophi within the genus Brachionus is remarkably constant. The fulcrum is short and broad. The rami are broad, rounded externally and have conspicuous anterior processes onto which some membraneous filaments between rami and unci are attached. The median edge of the rami are adorned with rows of zig-zag like processes, apparently complementary to the unci. These consist of fused teeth-like projections of the rami. The rami are hollow structures, each having two cavities. Openings of these cavities are evident in dorsal view as a pair of large holes, and in caudal view as a second, smaller pair of holes. Each uncus is a more or less pentagonal plate, composed of almost completely fused, subequal teeth, with a subuncus. The distal part of the unci fit in cup-shaped articulations of the manubria. Cavities in the proximal part of the manubria are covered by a membrane. The external margin of the manubria is characteristic: it is sickle-shaped, and bent inwards distally: By this shape, the manubria fit around the rami when inactive, with their tips curved ventrad. (ref. ID; 953)
ref. ID; 1663
Dorsal and ventral plate of lorica completely fused laterally. Anterior dorsal margin of lorica usually with four or six spines. Posterior margin with or without spines. Body moderately flattened dorso-ventrally. Foot long, annulated, retractile, not segmented. Two toes. Mastax malleate. Planktonic species. Some of species are common and highly variable, especially in hard waters. Sometimes dense populations. (ref. ID; 1663)
ref. ID; 2891
The genus contains, to date, 30 distinct polymorphic species. There has, until now, been no unified agreement among authors on the taxonomic boundaries of distinguishable form-series within the genus; this applies also to obligatory unified nomenclature (Pejler 1977). Kutikova (1970) gave many ecotypes (varieties) and modifications (forms) the rank of subspecies. Ruttner-Kolisko (1972, 1974) divided the genus into groups (Formenkreis); clusters of similar and recognized related species ranked together as the urceolaris group, patulus group, quadridentatus group and angularis group. In this author's revision of Voigt's (1956-57) taxonomic work (Koste 1978) on the Rotatoria-Monogononta, the genus is divided into the following Formenkreis: (1) Formenkreis patulus (including (?)donneri and leydigi), (2) Formenkreis quadridentatus (including bidentata), (3) Formenkreis urceolaris (including pterodinoides, plicatilis, baylyi, variabilis, novae-zealandia and satanicus), (4) Formenkreis havanensis-zahniseri (including falcatus), (5) Formenkreis mirus (including diversicornis), (6) Formenkreis calyciflorus (including dimidiatus, gillardi and budapestinensis), (7) Formenkreis angularis (including charini, kasadensis, dolabratus, caudatus and forficula; keikoa). The taxonomy of the genus has, to date, been based on characteristic features of the lorica. The following are distinctive; general shape, spines and form of the dorsal and ventral anterior and posterior lorica margins, the form and spines of the foot-opening, and the structure and tesselation (foundation pattern) of the lorica surface. Correlations of these morphological characteristics with autecological and synecological factors are recognized only in individual species, e.g. lengthening of caudal spines in B. calyciflorus and B. bidentata as a response to the carnivorous Asplanchna in the same environment (Gilbert 1966; Halbach 1970; Pourriot 1974). (ref. ID; 2891)
ref. ID; 3073
Caudal region of Brachionus-spp. (ref. ID; 3073)
Quote from ref. ID; 3073
The foot glands of Brachionus-spp. (ref. ID; 3073)
Quote from ref. ID; 3073
ref. ID; 3114
In this genus, the following characters are regarded by Ahlstrom (1948) and Gillard (1948) as the specific taxonomically important ones. 1. Number of the occipital spines (six, four, two, wanting). 2. Length of the anterior spine and position of the longest spine (the longest spines are: anterior lateral, antero-intermediate, anterior median spines). 3. Basal plate (present or absent). 4. Mental margin (flexible, rigid, with four spine like protuberances with median sinus, irregularly elevated toward center). 5. Posterior spines (present or absent: if present, the direction of development: widely apart at the base, or quite close together. 6. Extension of the dorsal plate (over or not overhanging on the foot opening: with or without kneelike swellings on the inner side near the base.) 7. Foot sheath (present or absent: if present, whether it is longer or not than the long spines). 8. Proportion in the length of the anterior spines to the medians (as in zahnersi and satanicus). 9. Ornamentation of the lorica. 10. Lateral view of the posterior part of the lorica (truncated or pointed). 11. Shape of the occipital spines (saw-toothed or not). 12. Lorica (divided or undivided into dorsal and ventral plate). 13. Foot opening (with or without anchor-shaped spines). 14. Length of the anterior median spines (in havanaensis and var. rahes). According to the Sudzuki's opinion, all of the above criteria have not always the same value as taxonomic characters for the species; of all, the features (shape) of the occipital spines are the most important. Next, the features of the mental margins, the features of the posterior are (except the spines) are important. Nevertheless such criteria as whether the metal margin is flexible or rigid, and as the presence of the kneelike swelling on the inner side near the base do not seem so serious. (ref. ID; 3114)
ref. ID; 4594
Body flattened dorso-ventrally. Dorsal and ventral of lorica completely fused laterally. Anterior dorsal edge of lorica with six or four spines; anterior ventral margin with central sinus, with or without spines. Posterior margin with or without spines. Foot annulate, with two toes. Mastax malleate. (ref. ID; 4594)
Collected from Lake Kasumigaura, JapanQuote from ref. ID; 3114
ref. ID; 110
Common planktonic rotifer inhabiting nutrient rich waters. Polymorphic species. The most illustrative field observations regarding form variation in B. calyciflorus come from Dieffenbach & Sachse (1911), Hartmann (1918), Wesenberg-Lund (1930), Ahlstrom (1933), Nayar (1965), Green (1960, 1970), Arona (1966), Halbach (1970), and Saksena & Sharma (1981). Investigations on form variations in laboratory cultures come from Buchner (1936), de Beauchamp (1937, 1938, 1952), Schneider (1963) and Buchner et al. (1957). Also, Pourriot (1957), Erman (1962, 1963), Galkovskaja (1963), Halbach & Halbach-Keup (1974), Starkweather & Gilbert (1977) have studied the food and food preferences of B. calyciflorus. Form variations and the food have been the subject of many reviews (Hutchinson 1967; Rutter-Kolisco 1974; Pourriot 1977; Dumont 1977; Pejler 1980; Satrkweather 1980). (ref. ID; 110)
ref. ID; 2393
Many types of the present species are observed, but it is difficult to set sharp boundaries between them. Their representative types observed in Japan are enlisted below; sometimes variety or form names are adapted for each type. (ref. ID; 2393)
typical type - Median occipital spines slightly longer than lateral ones, posterior spine absent.
amphiceros type - Median occipital spines slightly longer than lateral ones, posterior spines very long.
anuraeiformis type - Median occipital spines same as above, posterior spines short.
dorcas type - Median occipital spines much longer than lateral ones, posterior spines absent.
dorcas-spinosus type - Median occipital spines same as above, posterior spines one or two pairs.
Brachionus falcatus f. lyratus (ref. ID; 3069), var. lyratus Lammerman, 1908 (ref. ID; 1929) or Lemmerman, 1908 (ref. ID; 3114) reported author and year? (ref. ID; 3292)
Quote from ref. ID; 3069
Brachionus falcatus f. reductus Koste & Shiel, 1983 (ref. ID; 2759 original paper)
Brachionus falcatus var. hamatus Lemmerman, 1908 (ref. ID; 3114)
Brachionus forficula-group
Fixed sample
ref. ID; 3114
B. forficula is a quite variable species, the variation of the posterior spines being highly extensive even in the specimens collected from the same place. Namely, the posterior spines are usually parallel (f. volgensis-voronkowi), curve inwards (typicus-urawaensis), and divergent (f. divergens-minor); however, the direction of the spine is due to the condition of hatching, when the posterior spines are not yet stiffened, an their length and shape differ owing to the growth of the animals. It is true that the knee-like swellings are usually present at the inner side of the posterior spines near their base. However they may be lacking in such reduced forms as minor, angularis and urawensis. (ref. ID; 3114)
Quote from ref. ID; 3114Quote from ref. ID; 3114Quote from ref. ID; 3114
B. patulus O.F. Muller, B. patulus var. macracanthus Daday, 1905, B. polyacanthus (Ehrenberg, 1834) has remained unsettled. Ahlstrom (1940), Bartos (1959), Rudescu (1960), and Kutikova (1970) place all these taxa in the genus Platyias Harring, whereas others (Koste 1978; Koste & Shiel 1987 and Turner 1990) follow Wulfert (1965), who considers them to belong to Brachionus Pallas. The traditional character used to differentiate the B. patulus-group form Brachionus s. str., is the structure of the foot. It consists of three pseudosegments, which is reminiscent of the definition of Platyias. However, the high lorica, the presence of an eye and of a terminal foot aperture in these species argue in favour of their relationship to Brachionus, rather than to Platyias. (ref. ID; 953)
Soon after B. plicatilis started being used in aquaculture, it became apparent that groups of strains having different ecology and morphology occurred which were, for convenience, called 'S-' (small) and 'L-' (large) type. Recently, several studies were conducted to unravel the taxonomic relation between these two groups.
ref. ID; 1824
The original description of B. plicatilis by O.F. Muller (1786) corresponds well to the 'L-type'. Also B. muelleri Ehrenberg, 1834 and B. hepatotomus Gosse, 1934 can be identified as representing the 'L-type'. The description of B. spatiosus by Rousselet (1912) is inadequate to decide on its identity. The oldest recognisable description of the 'S-type' is that of B. roundiformis Tschgunoff, 1921, this name there for becoming the valid name for the taxon. The putative identity of some younger synonyms is followed.
B. plicatilis O.F. Muller, 1786
Synonyms;
B. muelleri Ehrenberg, 1834,
B. hepatotomus Gosse, 1851,
B. plicatilis asplanchnoides Charin, 1947,
B. plicatilis longicornis Fadeew, 1925,
B. rotundiformis Tschungunoff, 1921,
B. baylyi Sudzuki & Timmes, 1977
Species inquirendae;
B. spatiosus Rousselet, 1912,
B. plicatilis decemcornis Fadeew, 1925,
B. plicatilis ecornis Fadeew, 1925,
B. plicatilis murrayi Fadeew, 1925,
B. orientalis Rodewald, 1937,
B. plicatilis colongulaciens Koste & Shiel, 1980,
B. plicatilis estoniana Sudzuki, 1987
(B. urceolaris var. werneri Daday, 1903, listed as a synonym of B. plicatilis by Ahlstrom (1940) belongs to B. urceolairs rather than to B. plicatilis; the description of B. plicatilis magadensis Koste, listed in Koste & Sheil (1987) could not be traced.)
Names of taxa that were inadequately described or whose description includes peculiar characters that prevent their assignment to either of the two species are listed as nomina inquirendae. (ref. ID; 1824)
Evidence for species status of S and L type B. plicatilis.
1) Morphology (Fu et al. 1991): Differences in size and dorsal anterior spine shape.
2) Isozyme patterns (Fu et al. 1991): Differences between 37 L and 30 S strains.
3) Differences in sexual and asexual reproduction (Hirayama & Rumengan 1993).
4) Chromosome number (Rumengan et al. 1991): 2n=25 in S-type, 2n=22 in L-type.
5) Cross-mating experiments:
- no resting egg formation between S & L strains (Fu et al. 1993)
- male discrimination among S and L type (Rico-Martinez & Snell 1995; Gomez & Serra 1995)
- differential binding of the mate recognition pheromone (MRP) to S and L males (Rico-Martinez & Snell 1995) (ref. ID; 1824)
ref. ID; 3120
In B. plicatilis (O.F. Muller), the size and shape of lorica, and shape of spines vary greatly according rotifer strain (Serra & Miracle 1983, 1987; Snell & Carrillo 1984; Sudzuki 1987). In Japan, domesticated strains of the rotifer are divided into two groups, the so-called "S and L types". The division into S and L type rotifers is exceedingly important for fry production, because they exhibit differences not only in morphological characteristics but also in growth response to water temperature (Ito et al. 1981). The main morphological and physiological differences between the two types have been summarized in previous reviews (Fukusho 1983; Hirayama 1985). The S type has a small and round lorica, while that of the L type is comparatively large and slender. Another important difference is the shape of the anterior spines on the lorica. S type has pointed spines, while L type has obtuse angled ones. The most suitable temperature range for population growth of S type is higher (28-35 degrees C) than that of L type (18-25 degrees C). The lower temperature limits of S and L types for growth are 20 and 10 degrees C, respectively. (ref. ID; 3120)
ref. ID; 6942
The genetic diversity in the resting egg banks of the Brachionus plicatilis. (ref. ID; 6942)
ref. ID; 7066
Ecological genetics of Brachionus sympatric sibling species.
Allozyme and morphometric analysis showed that Brachionus group plicatilis (formerly, Brachionus plicatilis and currently split into B. plicatilis and B. rotundiformis) in habiting Torreblanca Marsh was composed of three groups of genotypes with no evidence of gene flow between them (B. plicatilis, B. rotundtiformis SM and B. rotundiformis SS). B. plicatilis is a euryhaline, low temperature group; B. rotundiformis SM is adapted to high temperature and low salinity conditions; and B. rotudiformis SS is adapted to high temperature and highy salinity conditions. (ref. ID; 7066)
The median pair of occipital spines are the longest and outcurved considerably. The characteristics of various types are as follows:
typical type - Posterior spines about one half or three quaters of body length, not so divergent.
melheni type - Posterior spines very long and divergent.
brevispinus type - Posterior spines about 1/8 to 1/3 length of body, somewhat divergent.
entzii type - Posterior spines almost rudimentary.
rhenanus - Posterior corners almost rectangular.
cluniorbicularis type - Posterior corners rounded.
Intermediate type between typical and melheni types; between entzii and rhenanus type; between rhenanus and cluniorbicularis types, etc. (ref. ID; 2393)
Brachionus aculeatus Gillard, 1948 (ref. ID; 1345); Brachionus angularis var. aculeatus Hauer, 1937 (ref. ID; 1345); Brachionus angularis var. aculeatus f. lateralis Hauer, 1937 (ref. ID; 1345); Brachionus caudatus var. aculeatus Ahlstrom, 1940 (ref. ID; 1345)
Comments
Brachionus angularis (var.) aculeatus Hauer, 1937 is considered by Ahlstrom as a variety of Brachionus caudatus (which in its turn is looned upon by Hauer as a (var.) of Brachionus angularis). Hauer (1937) admits that he has never met with intermediates between Brachionus caudatus and Brachionus aculeatus, although he was able to examine a very large material. On the other hand, both Brachionus caudatus and Brachionus aculeatus, are regularly found together (= sympatric species). They must accordingly be considered as two distinct species. Brachionus angularis (var.) aculeatus (f.) lateralis Hauer being part of the cyclomorphosis must be sunk into synonymy of Brachionus aculeatus. (ref. ID; 2328)
Parthenogenetic females: Lorica stiff, ventral and dorsal plates of lorica fused laterally and distally, their surface covered with minute warts. Shape nearly circular. Width of head aperture nearly 2/3 of lorica width, medio-ventrally with a pair of triangular projections and with an intermediate and a lateral pair of shallow lobes. Dorsally a pair of relatively long medium spines, separated by a deep U-shaped sinus, and a pair of short intermediate spines. Short, semi-longitudinal, diverging ridges run posteriad from the tips of the ventral and dorsal anterior projections. Semi-longitudinal ventral and dorsal folds present or absent. Apertures of the lateral antennae visible dorso-laterally, near posterior third of lorica. Foot opening ventrally a deep, inverse-V-shaped fissure, dorsally broader but shallower, with a slightly convex anterior margin. Edge of foot aperture a shallow ridge, projecting slightly posteriad and ventrad. Foot annulated, retractile ending in two conical toes. Trophi of the usual type is the genus. (ref. ID; 2897)
Mictic female: Mictic female as parthenogenetic one. (ref. ID; 2897)
Egg: Parthenogenetic egg and male egg elliptic, with soft, rippled or smooth shell, male egg slightly smaller than parthenogenetic egg. Resting egg elliptic, with hard, smooth shell. Shell consisting of three parts, separated by narrow fissures. (ref. ID; 2897)
Male: Male unknown. Probably present but contracted and deformed beyond recognition through fixation. (ref. ID; 2897)
Comments
The new species belongs to the B. urceolaris group, but is easily distinguished from these species by the absence of lateral antero-dorsal spines, and by its nearly circular lorica. Brachionus africanus sp. nov. might also be confused with congeners possessing four antero-dorsal spines. These specimens, however, have a softer lorica (B. calyciflorus Pallas and B. dimidiatus (Bryce)), longer antero-dorsal spines (B. calyciflorus and B. budapestiensis Daday) and a more elongate lorica, or a differently shaped ventral margin of the head aperture. The species also resembles the recently described B. postcurvatus Kuczynski, which has a different foot aperture and a smoothly concave ventral margin of the head aperture. (ref. ID; 2897)
Etymology
The specific name africanus is an adjective, referring to the continent to which the species appears endemic. (ref. ID; 2897)
Type locality
Fish pond at the Kenya Marine and Fisheries Research Institute, Sangoro Laboratory Compound, 35 degrees 16'E, 0 degrees 27'S, Kenya. (ref. ID; 2897)
Lorica oval, [greatest width]/[total length] ratio 0.81-0.82, the greatest width is somewhat below the middle of the lorica. Anterior dorsal margin with two median acute spines, laterals and intermediates absent. Anterior ventral margin rather undulate, somewhat elevated, without central notch. Foot opening with a U-shaped aperture and two short bluntly pointed protuberances in the ventral plate, relatively close together and convergent. Body pear-shaped in lateral view, [greatest depth]/[total length] ratio 0.6. Lorica smooth. Ahlstrom (1940) considered the existence of two series of variants in B. angularis. (ref. ID; 775)
Anterior occipital margin with two small median spines flanked by a U-shaped notch. Lorica stippled, with a pattern of cuticular plates on the dorsum. (ref. ID; 1805)
Lorica stippled. Two very small projections in the occipital margin. Posterior spines absent. Cosmopolitan in alkaline waters. (ref. ID; 1929)
Lorica stippled, with a pattern of cuticular plates on dorsum; anterior occipital margin with two median spines, flanked by a U-shaped notch. (ref. ID; 2704)
B. angularis is one of the more variable species of Brachionus. Many forms found in Sri Lanka lack intermediate spines in which case the occipital lateral margin invariably rounds off the middle to form median spines. Only the median spines are prominent and there is a deep sinus in between them. (ref. ID; 2715)
Lorica firm tightly stippled into a dorsal and ventral plate, compressed dorso-ventrally. Anterior dorsal margin with two median spines flanking a 'V' shaped sinus. Posterior spines absent. (ref. ID; 2867)
This species is characterized in having 1) only 1 pair of anterior median spines at the dorsal margin, 2) not so elevated pectoral margin with little undulation, 3) angular caudal portion, which sometimes reminds us of plump cheek and jaw of human beings and 4) caudal protuberances so strongly bent inwards or close together that basely observable from the dorsal side. The specimens depicted by Ahlstrom (1940, Pl.5, Figs.12-13) from Sholavaram lake, Madras, India and a form aestibus Skorikov, 1914 could belong to this species. (ref. ID; 3083)
The antero-lateral spines were absent in all specimens and sometimes even the intermediate spines are lacking. The cuticular protuberances on either side of the foot opening also varied. (ref. ID; 3086)
Anterior dorsal margin (occipital margin) with two median spines divided by a U-shaped sinus. Lateral and median occipital spines usually obliterate, may be weakly developed; intermediates more commonly developed than lateral. Mental margin (anterior ventral margin) rigid, somewhat elevated, with a shallow median sinus. Foot opening rather large, larger aperture in ventral plate, flanked laterally by cuticular protuberances. No posterior spines. (ref. ID; 3180)
Male: Male present. (ref. ID; 3064, 3065)
Quote from ref. ID; 3064
Measurements
Total length 115-119; greatest width 94-96; greatest depth 69-71 µm. (ref. ID; 775)
Total length 74-88; maximum width 65-70; anterior width 45-52 µm. (ref. ID; 1805)
Length of lorica 112; maximum width 84 µm. (ref. ID; 1929)
Total length 82-94; maximum width 62-68; anterior width 50-55 µm. (ref. ID; 2704)
Length of lorica 101; width 75 µm. (ref. ID; 2715)
Total length 110; length of lorica 100; maximum width 90; sinus 10 µm. (ref. ID; 2867)
Total length 80-102; width at the basis of occipital lateral spines 66-68; widest part 64-89; widest part/total length 0.78-0.87; occipital sinus 7-8 wide, 8-10 deep; distance between caudal protuberances at the base 16-18; distance between caudal protuberances at the distal end 5-8; thelytokous egg 60x41 µm. (ref. ID; 3083)
This species is distinguishable from angularis Gosse, 1851 in 1) obliteration of all spines at the anterior margin of dorsal lorica, especially in lacking median spines as usual form but 2) possessing caudal protuberances strongly projected over the body margin and 3) M-shaped caudal extremity on dorsal side: A-shaped sinus on ventral side. A form apicata Tschugunoff, 1921 may be included in this species. (ref. ID; 3083)
Measurements
Total length 137-154; breadth 104-120 µm. (ref. ID; 1402)
Length of lorica 150 µm. (ref. ID; 2860)
Total length 90-102; dorsal lorica length (without spines) 89-92; width at the basis of occipital lateral spines 52-57; widest part 70-80; widest part/ total length 0.72-0.82; occipital sinus 4-9 deep; caudal projection or protuberance 5-7 long, 4-5 wide; distance between caudal protuberances at the base 12; distance between caudal protuberances at the distal end 10-13; highest part 59-60; fertilized dormant egg 69-71x48 µm. (ref. ID; 3083)
The lateral occipital spines are well-developed in size as long as the median ones. The dorsal lorica is ornamented with indistinct patterns of cuticular ridges. On either side of the foot opening there develops a short spine. (ref. ID; 2393)
Easily distinguishable from all the other subspecies under angularis by possessing a straight pectoral margin. This character was figured simply by Voigt (1957, Plate 19, Fig.2c). (ref. ID; 2874)
Locality
Minami-Daito Jima site 4. (ref. ID; 2874)
Measurements
Lorica length 100; widest part 78; width at the anterior extremities 70; occipital median sinus 10; caudal projection 9x5 µm. (ref. ID; 2874)
This species had the closet relation with the bidens group of angularis in outer appearance, but differed markedly from it in having 1) double decked triangular dorsal projections at the caudal region (upper projections at the caudal region (upper projection like that of sericus Rousselet, 1907), and 2) spine-like toes. Besides, the features of foot opening, which reminds us of nilsoni, Ahlstrom, 1940 are different. (ref. ID; 2587)
This species resembles angularis Gosse in lacking any anterior spines but medians on the dorsal lorica and caudal protuberances are strongly bent similar to aestivus Skorikov, 1914 but differs from it in having 1) extraordinarily truncated antero-lateral corners, 2) two lobed Keratella typed pectoral margin and 3) rather square or near octagonal lorica more or less like B. budapestinensis. (ref. ID; 3083)
Etymology
Named after Prof. D.H. Murphy, Department of Zoology, Faculty of Science, National University of Singapore for warm cooperation at the field collection. (ref. ID; 3083)
Type locality
A pond for ducks in the Science Centre, Singapore. (ref. ID; 3083)
Characterized by 1) relatively long antero-lateral spines, 2) undulated (4 lobed, not triangular as in caudatus) pectoral margin, 3) parallel or convergent caudal protuberances, 4) club-shaped knobs covered with minute papillae like those of lyratus Shephard, 1911 at the distal end of the caudal protuberances and 5) lack of anterior intermediate spines. Different from lylatus Shephard in 1) wanting intermediate spines of dorsal lorica, 2) slowly tapering anterior half of lorica and 3) the type of pectoral margin. Some of the specimens by Ahlstrom (1940, series beta), at least, those indicated as Figs.8-9 and 11 and have also superficial alliance with this group. (ref. ID; 3083)
Type locality
Krangi reservoir. (ref. ID; 3083)
Measurements
Total length 88-122; dorsal lorica length (without spine) 78-102; width at the basis of occipital lateral spines 55-68; widest part 89-98; distance between caudal protuberances at the base 18-29; widest part/total length 0.75-0.80; middle part 60-66 high; anterior median sinus 10-12 deep; anterior lateral spines 3-8; caudal projection or protuberance 10-20 long, 8-10 wide; club-shaped knobs 11-12x10-12; fertilized dormant egg 50-64x45-51 µm. (ref. ID; 3083)
This species is characterized by having a wider and rounding posterior half of the lorica reminding us of keikoa Koste, 1979, but it clearly differs from keikoa in the features of both caudal sinus and those of caudal half of the lorica. The former is very deep and complicated in structure and the latter simply round in keikoa. Besides, neck region is different (usually distinguishable in pseudokeikoa). (ref. ID; 2874)
Locality
Ishigaki Jima 4A. (ref. ID; 2874)
Measurements
Lorica length (LL) 95-120; widest part (WP) 85-102; WP/LL 0.85-0.89; highest part 67; width at the anterior extremities 51-65; elevation of pectoral margin 5-10; neck region 10-25x55-70; occipital median sinus 8-10 µm. (ref. ID; 2874)
This species is firstly classified into the angularis group, since it is provided with only a pair of median spines at the frontal margin of the dorsal plate. It superficially resembles keikoa and pseudokeikoa; but is, sharply separable from the former in 1) lacking a deep and wide caudal notch, 2) having a smooth pectoral margin and 3) showing different egg carrying behavior; from the latter in lacking a) an angular caudal region, b) lateral spines (though very short in pseudokeikoa) and c) two-lobed pectoral margin; and, from both in having two constrictions on the lorica (one at the mastax region, another at the base of the caudal prolongation), and a big ventrally projected caudal elongation with a pair of spoon-like protuberances bent inwards. On this point, it resembles pinneenaus, which is, however, characterized by having 1) lateral spines at the occipital margin and 2) distinctly ridged dorsal and ventral lorica. In pyriformis, the pectoral margin is similar to that of budapestinensis in type. (ref. ID; 2587)
Measurements
Lorica length (without spines); 80-100, greatest width; 62-83, width at the anterior extremity; 25-40, width at the base of caudal projection; 30-50, caudal elongation; 40-50x10-30, spoon-like projections; 15-20x25-30, occipital median sinus; 10-15, thelytokous egg; 55-62x35-40 µm. (ref. ID; 2587)
This species presents a series of variants, with or without posterior spines and their place of origin may also differ in different specimens. (ref. ID; 1805)
Lorica with dorsal, ventral and basal plates. Six occipital spines of which the laterals and the medians are of the same length. Mental margin slightly convex without a defined central notch. Lorica lightly stippled. (ref. ID; 1929)
Overall length 200 µm, lateral anterior spines one-fifth longer than medians, intermediates almost obsolete. Mental ridge elevated and undulating. Basal plate well developed, posterior spines wanting. In addition to morphological differences between this species and cyclomorphic forms of B. quadridentatus the latter has so far not been found in waters below 18 degrees C in temperature. The specimens were therefore considered to be variations of B. bidentata. (ref. ID; 2278)
Measurements
Total length 155; maximum width 108; anterior width 90 µm. (ref. ID; 1805)
Total length 196; maximum width 154; width at anterior margin 112; anterior spines 28, 14, 28 µm. (ref. ID; 1929)
Total length 160; maximum width 110; anterior width 90 µm. (ref. ID; 2704)
Brachionus bidentata f. adorna Wulfert, 1966 (ref. ID; 1805, 2064 original paper)
Measurements
Total length 150; maximum width 124; anterior width 96 µm. (ref. ID; 1805)
The lorica shows comparative similarity to that of B. bidentata f. inermis (Rousselet) 1906. The latter however has long marginal spines, absent in minor. Moreover, this morph is an intermediate to B. bidentata f. testudinarius (Jakubski) 1912, which has a short curved posterior spine. In the new subspecies the posterior border of the lorica is specifically semicircular. Comparison with B. bidentata f. jirovci (Bartos), 1947. Syn: B. furculatus var. jirovci Bartos, 1947 (Hauer 1963; Kutikova 1970) shows that this infrasubspecies taxon in contrast to B. bidentata minor, has forked marginal spines, and also occasionally posterolateral spines. Considering the great variability of the species B. bidentata an exact taxonomic classification of the different morphs is difficult. For example, with regard to length of lorica spine development, Pourriot (1974) showed experimentally that this depended on the presence of the predator Asplanchna brightwelli. The new subspecies is considered here as a "dwarf-form" sensu Green's (1977) study, where food-storage salinity of bitope, etc., caused a reduction of lorica-size in crater lake rotifers. Therefore the classification of B. bidentata minor as a subspecies i.e. a genetically distinct form, is provisionally documented here, noting however that only a single collection is involved. (ref. ID; 2758)
Measurements
Lorica length 120-156; lorica height 52-80; greatest lorica width 84-108; range of marginal spines 72-104 µm. (ref. ID; 2758)
Forked marginal spines are absent, however, and the dorsal lorica is unstructured. The lorica has a resemblance to Brachionus quadridentatus var. ancylognathus (Schmarda, 1859), but the elongated marginal spines, distinct lorica basal plate and the tube-like foot orifice indicate that this is a morph of B. bidentata. (ref. ID; 2758)
This Taiwanese species is characterized by 1) longest laterals and shortest intermediates (i.e. 2-3-1 or 1-2-1 in formula), 2) branched lateral spines, 3) trapezoid lorica, 4) no pectoral median sinus but flexible nearly straight or slightly concave margin and 5) very small body size. (ref. ID; 3083)
Comments
Brachionus jirovici Bartos, 1942 seems to belong to this group. (ref. ID; 3083)
Measurements
Lorica length 164; greatest lorica width 140; marginal spine length 68; posterior spine length 100 µm. (ref. ID; 2758)
Total length 138; width at the basis of occipital lateral spines 80; widest part 118; anterior median sinus 14 wide, 21 deep; anterior lateral spines 30; anterior intermediate spines 14 µm. (ref. ID; 3083)
Lorica subcircular to moderately oval, its greatest width is in the middle or a little below the middle of the body. Insertion of basal plate in the beginning of the posterior third of the lorica. Rather highly placed foot opening. Anterior dorsal margin with six spines, laterals about two times longer than medians and medians about two times longer than intermediates. Anterior ventral margin straight, without sinus. Anterior spines stout, straight, medians relatively close together forming a narrow and deep sinus. Posterior lateral spines stout, straight, representing about 1/5 to 1/4 of total length. The whole surface of the lorica, including the anterior and posterior spines, is covered by a pustulated or granulous pattern. (ref. ID; 775)
Lorica with dorsal, ventral and basal plates. Six anterior spines, of which laterals and medians are longer than intermediates and are of some length. Forms with bifurcated antero-lateral spine have also been found in our sample, which was not reported earlier from India. (ref. ID; 2867)
Measurements
Total length 232-286; greatest width 138-157; anterior lateral spines 33-48; anterior intermediate spines 10-16; anterior median spines 21-24; posterior lateral spines 43-82 µm. (ref. ID; 775)
Total length 250; length of lorica 200; maximum width 180; length of antero-lateral spine 40; length of antero-median spine 15; length of antero-intermediate spine 20; length of posterior spine 20 µm. (ref. ID; 2867)
Lorica oval, great width/total length ratio 0.57-0.85, The greatest width is usually a little below the middle of the lorica. Anterior dorsal margin with six spines, medians an intermedians almost equal in length, laterals not much longer than the other spines. (The relative length of anterior dorsal spines may show many individual variations). Anterior ventral margin straight, without sinus; it may be undulate or slightly convex. Posterio-lateral spines absent. Foot sheath flanked by two bluntly pointed spines slightly asymmetrical. Lorica smooth. (ref. ID; 775)
Measurements
Total length to 244; greatest width to 188; anterior lateral spines to 27; anterior intermediate spines to 10; anterior median spines to 20; subitaneous egg 75-110/55-84 µm. (ref. ID; 775)
Lateral and median occipital spines curved inward; basal plate little marked; lateral posterior spines lacking; median posterior spines blunt. Foot-opening not tube-shaped, situated on or near the posterior margin of the ventral plate. Opening of the lateral antennae at the end of the body, marginal, near the junction of the dorsal and the basal plate. Dorsal plate with a well-marked pattern of ridges, forming a characteristic ornamentation: two hexagonal and one pentagonal median panels, all flanked by two pairs of three trapezoid lateral panels. Ridges on the ventral plate less marked or almost lacking: two anterior ridges, convex or convex-concave and two curved posterior ridges, each parallel in its extreme part to the sides of the foot-opening. Between these two pairs of ridges, a variable and scarcely marked pattern of curved lines may be observed. (ref. ID; 1808)
Measurements
Length of lorica 100-110; width of lorica 72-83; height of lorica 60; distance between marginal occipital spines 53-55; width of foot-opening 13-18; height of foot-opening 10; depth of anterior median indentation 10-17 µm. (ref. ID; 1808)
Brachionus bidentatus Anderson var. ambidentatus De Ridder, 1991 (ref. ID; 2935 original paper)
Descriptions
This morph is near, as to broad posterolateral spines, to B. bidentatus f. crassispineus Hauer, 1963, but it is smaller (total length 210 µm, B 115 µm, distance between posterolateral spines 175 µm) and less rectangular. Moreover, the head opening has two more spines than the nominate form and all the varieties known intherto. (ref. ID; 2935)
Locality
It found in freshwater, in plankton of pools in Oued Djerat, on 31.05.1978. (ref. ID; 2935)
At a glance, this species was thought to be a deformation of Schizocerca diversicornis Daday, 1883, but two facts, 1) all the specimens encountered were short spined forms and 2) not a single specimen of such long spined forms as diversicornis appeared in the same habitat revealed that this population could be an independent species separate from diversicornis. This species characteristically lacks 1) longer spines at frontal and caudal regions, and 2) constriction on the caudal region such as that in diversicornis. This species was abundant here. No intermediate forms between diversicornis and brevispina were found. (ref. ID; 2587)
Measurements
Total lorica length; 150-220, lorica length (without spines); 128-200, greatest width; 73-110, width of anterior extremity 90-95, width of posterior extremity 55-60, lateral spine (occipital) 18-30, lateral spines (pectoral) 10-12, pectoral elevation 8-12, occipital median spines 7-10, occipital median sinus 11-20, pectoral median sinus 3-5, caudal ventral extension 10-15, posterior spines (dorsal; left 8-30, right 10-12), posterior spines (ventral left 2-5, right 5-10), thelytokous egg 95-100x55-60 µm. (ref. ID; 2587)
Anterior occipital margin with four spines; medians longer than lateral and curving ventrally. Lorica tuberculate and with a pattern of cuticular plates on the dorsal and ventral side. (ref. ID; 1805)
Lorica firm and sturdy. Foot opening more or less rounded. In some cases the lorica is lightly stippled. (ref. ID; 2715)
Male: Male present. (ref. ID; 3065)
Quote from ref. ID; 3065
Egg (male): (ref. ID; 3064)
Quote from ref. ID; 3064
Measurements
Total length 128; maximum width 90; anterolateral spines 18; median occipital spines 30 µm. (ref. ID; 1805)
Total length 150-200 µm. (ref. ID; 2715)
Length of ventral lorica 148 µm. (ref. ID; 2891)
Total length 92-96; width at the basis of occipital lateral spines 60-64; widest part 65-69; anterior median sinus 8 wide, 20 deep; anterior lateral spines 20; pectoral median sinus 39 wide, 6-8 µm deep. (ref. ID; 3083)
Lorica oval to subcircular, greatest width/total length ratio varies from 0.58 (in individuals having very elongate body) to 0.76 (in individuals having a very globose body), though most specimens have a ratio falling between 0.64-0.69. Anterior dorsal margin with four spines, medians 1.3-2.0 times longer than laterals. Anterior ventral margin elevated, slightly notched medially. Lateral posterior spines absent. Foot opening usually with two broad-based, bluntly pointed spines. Lorica smooth. (ref. ID; 775)
Lorica flexible, very slightly compressed dorso-ventrally and oval in shape, not separated in dorsal and ventral plates. Antero-dorsal margin with four broad based spines of variable length, medians longer than lateral. Posterior spines four, but postero-lateral spines may not be present in some specimens. (ref. ID; 2867)
Lorica rather flexible, oval, not separated into a dorsal and a ventral plate; body little compressed dorso-ventrally. Occipital margin with four, broad-based spines of variable length, medians longer than laterals. Mental margin rather flexible, usually somewhat elevated with a shallow V- or U-shaped notch which is unflanked. Posterior spines may or may not be present. (ref. ID; 3180)
Lorica rather flexible, oval, not separated into a dorsal and ventral plate. Anterior dorsal margin with four, broad-based spines of variable length. Posterior spines usually absent; present only on some varieties. Freshwater species, but encountered in estuaries. (ref. ID; 4594)
Egg: Three types of dormant egg. (ref. ID; 3114)
Quote from ref. ID; 3114
Male: Male present. (ref. ID; 3064, 3065, 3114)
Quote from ref. ID; 3064Quote from ref. ID; 3114
Remarks
Brachionus calyciflorus Pallas is considered a cosmopolitan species but it is confined to alkaline fresh and brackish habitats. B. calyciflorus is an exceedingly variable species morphologically. It is usually rather flexible, and the lorica is not separated or only partly separated into dorsal and ventral plates and slightly or not compressed dorso-ventrally. The lorica is smooth or lightly stippled. It has four broad-based spines on the anterior dorsal margin which change in length and form. The ventral lorica margin is rather flexible with a V- or U-shaped median notch. The posterior lorica margin is oval, with or without posterolateral and posteromedian spines flanking the foot openings which also vary in their size and form. The variability of B. calyciflorus as in other Brachionus species has been a subject of many investigations (e.g., Green and Oey 1974). (ref. ID; 7847)
Measurements
Total length 190-260; greatest width 120-165; greatest depth 110-150; anterior lateral spines 16-23; anterior median spines 25-40; subitaneous egg 92-100/72-78; resting egg 110-130/70-97; male 90-105 µm. (ref. ID; 775)
Total length 490; width 420; anterior median spines 65; anterior lateral spines 47; posterior lateral spines 25; posterior median spines 22 µm. (ref. ID; 2715)
Length 200 µm. (ref. ID; 2860)
Total length 270; length of lorica 160; maximum width 110; length of antero-lateral spine 40; length of antero-median spine 50; length of postero-lateral spine 100; length of postero-median spine 70 µm. (ref. ID; 2867)
Total length 200-400; width 130-300 µm. (ref. ID; 4594)
This form has characteristically well developed postero-median and antero-median spines. B. calyciflorus f. amphiceros, B. calyciflorus f. calyciflorus, and B. calyciflorus f. dorcas were different from B. calyciflorus in the following prominent morphometric features; 1. Length of lorica with spines in calyciflorus, dorcas and amphiceros forms is 0.351 mm, 0.260 mm and 0.299 mm, respectively. 2. Length of lorica without spines in f. calyciflorus is 0.260 mm, in f. dorcas 0.195 mm and in f. amphiceros 0.195 mm. 3. Breadth of lorica in forms calyciflorus, dorcas and amphiceros is measured as 0.208 mm, 0.182 mm and 0.195 mm. 4. Length of antero-median spines is greatest (0.065 mm) in the form dorcas, and length of antero-lateral spines in the first two forms is equal, i.e. 0.039 mm and in amphiceros it is 0.052 mm. 5. Length of postero-median spines in the forms calyciflorus and amphiceros is 0.026 mm and 0.039 mm, respectively. 6. Length of postero-lateral spine in the form amphiceros is 0.098 mm. 7. The ratios between length of lorica and breadth of lorica in the three forms, viz. calyciflorus, dorcas and amphiceros are 1.25, 1.07 and 1.15 respectively. 8. Length of postero-lateral spines/length of lorica in the form amphiceros is 0.40. 9. The relation between length of the antero-median spines and postero-lateral spines in the form amphiceros is 0.83. 10. Lengths of antero-median spines/lengths of lorica in all three forms are 0.20, 0.33 and 0.33, respectively. (ref. ID; 110)
Lorica rather rectangular in shape, greatest width/total length ratio 0.42-0.45. Anterior spines taper pointed, about equal in length, medians may be slightly longer than laterals. Anterior ventral margin somewhat elevated toward the center, notched medially. Posterior spines long and pointed; posterior laterals stout and broad-based, 1.5-2.0 times longer than the anterior median spines. (ref. ID; 775)
Measurements
Total length 283-290; greatest width 126-130; anterior lateral spines 51-55; anterior median spines 57-60; posterior lateral spines 79-104; posterior median spines 62-65 µm. (ref. ID; 775)
Length of ventral lorica 220 µm. (ref. ID; 2891)
Lorica oval to pear-shaped, greatest width/total length ratio 0.58-0.62. Anterior dorsal margin with four broad-based spines, medians slightly longer than laterals. Anterior ventral margin with a central notch, that may be flanked by a papilla-like process on either side. Posterior median spines vary from short and rounded to acutely pointed and equal in length to the posterior laterals. The latter are relatively short, they may be slightly longer than the anterior median spines. (ref. ID; 775)
This species is characterized by 1) rather stiff pectoral margin with a pair of triangular median projections, 2) accessory swelling at the outer base of occipital median spines and 3) occipital median spines a little longer than the laterals (cf. dorcas Gosse, 1851) (ref. ID; 3083)
B. calyciflorus borgerti Apstein was described in 1907 from Colmbo Lake of Ceylon (now Sri Lanka) as B. amphiceros var. borgerti. Later Ahlstrom (1940) suggested that this rotifer should be named B. calyciflorus Pallas f. borgerti. Taking ino consideration the morphological specific characters and its geographic distribution, this tropical rotifer is separated by us as a subspecies. (ref. ID; 7847)
Redescription: Lorica slightly rigid, sometimes separated to definite dorsal and ventral plates, nearly oval, transparent, usually slightly stippled. Dorsal anterior margin with four broad-based spines slender at their tips, median spines longer than laterals. Deep V-shaped groove between anterior median spines which have saw-shaped teeth near the base. Anterior vental margin usually somewhat elevated with well marked median notch between short oval or nearly triangular protuberances. Posterior lorica magin usually with short lateral spines of equal length or which are clearly rounded. Sometimes one lateral spine absent. Foot opening nearly tube-shaped rather thick with characteristic dorsal and ventral notch. Ventral notch deeper, with distinct rounded bulge on internal margin. Dorsal notch usually rather small, its internal margin nearly a straight line. On its side, the foot opening has a triangular lateral projection. Trophi of mastax similar to those of all other species of the genus Brachionus. Each uncus has five large distinct and two small additional teeth (Koreneva 1985). (ref. ID; 7847)
Measurements: Lorica length 246-378 µm, excluding spines, width 154-223 µm, length of anterior dorsal median notch 50-85 µm, length of anterior dorsal spines: median 39-62 µm, lateral 27-58 µm, depth of anterior median ventral notch 10-15 µm, length of posterolateral spines 19-62 µm, depth of foot opening: dorsal interior 15-19 µm, dorsal width 23-46 µm, ventral interior 19-38 µm, ventral width 18-35 µm. Sizes of eggs: amictic 146-154x123-154 µm, mictic "male, male" 69-85x62-69 µm. (ref. ID; 7847)
Diagnostic characteristics: Diagnostic characteristics of Brachionus calyciflorus borgerti are the structure of the anterior dorsal and ventral lorica margins and the shape and structure of the foot opening. This subspecies includes the "B. pala var. willeyi" described by Apstein (1907) simultaneously with var. borgerti. It was distinguished from B. calyciflorus borgerti by the absence of posterior lateral spines but since it is based only on this character it can be considered as a morpho of the subspecies borgerti. (ref. ID; 7847)
b) The next form which we have designated "b", is intermediate in features between B. calyciflorus borgerti and B. calyciflorus typica (Figs.8-9). It has a lorica similar to that of B. calyciflorus borgerti and with a similar structure of the foot opening. It is notable for its structure of the dorsal anterior spines. These spines have a broad base but lacks a saw-like basal tooth. Probably this intermediate form may be a hybrid. The lorica of this form is sometimes slightly separated into dorsal and ventral plates. Posterior lateral spines are sometimes lacking. Anterior dorsal spines are not equal, lateral spines shorter and almost median. Ventral anterior margin with distinct outstanding median notch. The size of this form varies. (ref. ID; 7847)
Measurements: Lorica length 196-416 µm, width 100-294 µm, depth of anterior dorsal median notch: 46-108 µm, length of anterior dorsal spines: median 39-85 µm, lateral 31-54 µm, length of posterolateral spines 23-58 µm. (ref. ID; 7847)
c) Another form, "c", found by us is easily distinguished by a very large Asplanchna like body (Figs.10-11). Lorica very flexible, bag-like, not separated into dorsal and ventral plates and not compressed dorsoventrally. The greatest thickness and width of body is at about two-thirds of lorica length from anterior end. Anterior dorsal spines with broad, usually swollen bases, rather short and equal in length or median spines longer than lateral and with acutely pointed ends (as in f. dorcas). Posterior part of lorica mostly without spines but sometimes with one or two lateral ones, though long. A very swollen posterior part of the dorsal plate displaces the foot opening on the ventral side. The foot opening is flanked ventrally by large transparent, nearly triangular spines. (ref. ID; 7847)
Measurements: Lorica length 308-485 µm, width 216-308 µm, thickness 231-285 µm, depth of anterior dorsal median notch 77-108 µm, length of anterior dorsal spines: median 54-77 µm, lateral 39-77 µm, length of posterolateral spines up to 77 µm. Size of amictic eggs 131-146x116-123 µm. (ref. ID; 7847)
d) The form referred to as typical B. calyciflorus (f. "d") are comprised of rotifers easily distinguished by lorica structure and spines (Figs.12-14). The peculiarities of some forms are rather specific for particular regions and waterbodies and these can perhaps be illustrated by examples from Australia, Costa Rica, and the Philippines. The forms from ponds, especially those without posterolateral spines, were smaller than rotifers from lakes and resevoirs. Anterior dorsal median spines of this form can sometimes be longer (f. dorcas Goose) and posterolateral and foot opening spines are long (f. amphiceros Ehrb., f. spinosus Wierz.). (ref. ID; 7847)
Measurements: The pond forms: lorica length 158-223 µm, width 92-154 µm, length of anterior dorsal spines: median 15-54 µm, lateral 15-39 µm, length of posterolateral spines 15-123 µm. The lake forms: lorica length 270-400 µm, width 146-293 µm, length of anterior dorsal spines: median 54-92 µm, lateral 39-69, length of posterolateral spines 77-216 µm. (ref. ID; 7847)
Measurements
Max. length 300; max. width 175; ant. spines middle 50, lateral 30 µm. (ref. ID; 2704)
Total length 160-256; width at the basis of occipital lateral spines 80-110; widest part 100-148; anterior median sinus 20-42 wide, 35-61 deep; anterior lateral spines 22-38; pectoral median sinus 20-24 wide, 9-10 µm deep. (ref. ID; 3083)
This form is characterised by the absence of both postero-lateral and postero-median spines. The antero-median spines are well developed. (ref. ID; 110)
Median occipital spines twice longer than the laterals. Lorica smooth, oval, without postero-lateral and posterior spines. (ref. ID; 1929)
Characterized in having extraordinarily projected stick-like median spines and stiff triangular pectoral projections as borgeti. (ref. ID; 3083)
Measurements
Total length 308; maximum width 210; width at anterior margin 168; anterior median spines 112; anterior lateral spines 56 µm. (ref. ID; 1929)
Max. length 310; max. width 210; ant. spines middle 120, lateral 60 µm. (ref. ID; 2704)
Total length 125-129; width at the basis of occipital lateral spines 62-65; widest part 83-85; anterior median sinus 17 wide, 24 deep; anterior lateral spines 15-18; pectoral median sinus 12 wide, 5 µm deep. (ref. ID; 3083)
The lorica is very slightly compressed dorsoventrally and oval in shape which is not separated into dorsal and ventral plates. Anterior end bears four broad based spines. The antero-median spines slightly larger than the antero-lateral spines. The anterior margin is elevated into a shallow V-shaped notch ventrally. Posterior spines are absent and only one i.e., left postero-lateral spine is present. Because of certain peculiarities in morphological characteristics, the specimen is proposed to be designated as B. calyciflorus f. heterospina. The same is characterised by the presence of single postero-lateral spine on the left side and absence of posterior spines. (ref. ID; 2866)
Measurements
Length of lorica with spines 0.386; length of lorica without spines 0.315; breadth of lorica 0.257; length of antero-median spine 0.071; length of antero-lateral spine 0.057; length of left postero-lateral spine 0.043 mm. Length of lorica/breadth of lorica 1.22; length of antero-median/length of lorica 0.23; length of postero-lateral spine/length of lorica 0.13; length of antero-median spine/length of postero-lateral spine 1.67. (ref. ID; 2866)
This form is characterized in providing with 1) needlelike occipital median spines, 2) thick caudal extension like a bdelloid foot contracted and 3) two lobed pectoral margin. (ref. ID; 2874)
Measurements
Lorica length 70-80; widest part 40-58; occipital median sinus 10 µm. (ref. ID; 2874)
This form resembles f. anuraeiformis Brehm (1909) it differs from it in the presence of saw-tooth like outwards extensions from the base of the median occipital spines and prominent short spines flanking the median sinus of the anterior ventral margin. Also it resembles f. borgerti Apstein (1907) in the presence of saw-tooth like outward extensions from the base of occipital spines. It differs from it in the presence of prominent short spines flanking the median sinus of the anterior ventral margin. Hence this form has been recognized as a new variety of Brachionus calyciflorus. (ref. ID; 1929)
Descriptions
Lorica flexible, smooth and not separated into a dorsal and a ventral plate. Anterior dorsal margin with broad based, stout spines with round tips. Saw-tooth like prominent outward extensions are present from the base of the median spines. Median spines slightly longer than the laterals. Anterior ventral margin having a V-shaped median sinus, flanked by prominent short spines. Postero-lateral spines and the posterior spines flanking the foot opening. (ref. ID; 1929)
Polymorphic species. Anterior dorsal margin with two short median spines, lateral and intermediate spines somewhat developed or absent. Anterior ventral margin variable. Posterior spines stout. (ref. ID; 775)
Four occipital spine, the lateral slightly longer than the medians. Posterior spines long. (ref. ID; 1929)
B. caudatus is a highly variable species. The variability has been studied in detail by Green (1960). The posterior spines vary from little developed to well developed and even asymmetrically developed. Among the anterior spines the lateral spines may or may not present be. Specimens with different degrees of development in anterior and posterior spines were found in the same sample. This species is restricted to the tropical region unlike most Brachionus species. (ref. ID; 2715)
Occipital margin with two median spines separated by a U-shaped sinus, lateral spines developed in some forms; intermediates rarely developed. Mental margin rigid, slightly elevated, at times undulate, with a shallow median sinus. Lorica terminating in two stout posterior spines, separated at their bases by about half the width of the lorica, usually divergent and strongly flexed ventrally. Foot opening between bases of posterior spines, with a U-shaped aperture in the ventral plate; dorsal plate overhanging foot opening with a V-shaped extension of lorica. (ref. ID; 3180)
Comments
In the caudatus and dichotomus groups there is seen a caudally-inflexed elongation of the dorsal lorica. In dichotomus, however, this is terminated by a species-specific, bordered and domed tongue-shaped plate. Foot-opening spines of variable length and form occur only in the angularis group. They are absent in the taxa B. caudatus and B. dichotomus. Instead these possess narrowly-framed asymmetrical posterolateral spines of variable length. (ref. ID; 3191)
Measurements
Total length 182; width of anterior margin 98; anterior lateral spines 14; posterior spines 56 µm. (ref. ID; 1929)
Total length 153; width 114; anterior median spines 9; anterior lateral spines 3; right posterior spines 18; left posterior spine 12 µm. (ref. ID; 2715)
Length of lorica 180-210 µm. (ref. ID; 2860)
This species differs from most caudatus groups hitherto known in having 1) knoblike protuberances at the outer base of anterior lateral spines, which are usually directed outward, 2) obliterated intermediate spines of dorsal lorica, 3) triangularly undulated pectoral margin, at the tip of which 1 nipple-like projection, 4) angulated posterior half of the dorsal lorica like angularis, 5) caudal extremity with V-shaped prominence at the dorsal side, A-shaped sinus on the ventral side and 6) highly variable posterior projections mostly between 1/4-1/5 the total body length, and always convergent. Easily distinguishable from forficula even from reduced groups, since the feature of pectoral margin of forficula is of budapestinensis or Keratella in type. (ref. ID; 3083)
Measurements
Total length (TL) 150-236; dorsal lorica length (without spines) 124-150; width at the basis of occipital lateral spines 70-86; widest part (WP) 102-136; anterior median sinus 8-9 wide, 18-22 deep; anterior lateral spines 9-11; distance between caudal protuberances at the base 34-50; WP/TL 0.56-0.68; caudal projection or protuberance (CP) 30-64; CP/TL 0.20-0.27; fertilized dormant egg 76x55; thelytokous egg 76-80x58-62 µm. (ref. ID; 3083)
The shape of the lorica varies from oval (greatest width at the middle of the lorica) to pear-shaped (greatest width about 4/5 of the length from the anterior end); [greatest width]/[total length] ratio 0.42-0.64; [width at the tips of the anterior lateral spines]/[greatest width] ratio 0.65-0.84. Anterior dorsal margin with six short spines, medians longest. Anterior ventral margin variable, may be undulate, with a broad-based shallow median sinus or lobulate, slightly indented medially. Posterior spines stout, representing about 1/3 of total length, usually divergent, width at their tips/[greatest width] ratio 0.52-0.87. Lorica smooth. (ref. ID; 775)
Measurements
Total length 180-215; greatest width 75-116; width of the tips of the anterior lateral spines 63-76; posterior lateral spines 43-76; subitaneous egg 70-82x50-53 µm. (ref. ID; 775)
Anterior dorsal margin with two median spines. Anterior ventral margin undulate. Posterior spines long, straight, representing about 1/2 of total length. Lorica smooth. (ref. ID; 775)
Differs from other caudata groups in lacking 1) anterior intermediate spines, 2) long convergent posterior projections, 3) longest anterior median spines but in having, 4) anterior lateral spines nearly same as medians in length, 5) angular posterior portion. The main difference of singapurensis from ahlstromi Lindermann, 1939 in found in possessing short and straight caudal projections, obliterated nipple on the pectoral margin and smaller size. No intermediate forms have been recognized between them. The specimen from Java by Hauer (1937: 366, Fig.6, c) may be classified into this species. The difference from incertus Hauer, 1953 is found in features of both pectoral margin and caudal protuberances. (ref. ID; 3083)
Type locality
Krangi reservoir. (ref. ID; 3083)
Measurements
Total length (TL) 130-176; dorsal lorica length (without spines) 148-156; width at the basis of occipital lateral spines 83-85; widest part (WP) 95-126; anterior median sinus 8-10 wide, 14-22 deep; anterior lateral spines 10-20; WP/TL 0.69-0.72; ventral lorica length (without spines) 120; elevation of pectoral margin 8; distance between caudal protuberances at the base 38-40; caudal projection or protuberance (CP) 10-25 long, 9 wide (sometimes asymmetrical); CP/TL 0.13; fertilized dormant egg 60x50 µm. (ref. ID; 3083)
The anterior median and lateral spines are of the same length. The inward projection from the posterior spines are prominent. Posterior spines equal length. (ref. ID; 2715)
The auxiliary spines were very pronounced. (ref. ID; 3181)
Measurements
Total length 134; max. width 85; anterior width 65 µm. (ref. ID; 2704)
Total length 133; width 81; anterior median spines 12; anterior lateral spines 12; posterior spines 33 µm. (ref. ID; 2715)
Length of lorica 192; maximum width 127 µm. (ref. ID; 3181)
Described by Ahlstrom as a ((variety)) of Brachionus angularis; it differs in being much smaller (75-102 µm), in possessing lateral anterior spines and a differently shaped foot-opening. Again, no intermediate forms are known, and as Brachionus chelonis and angularis have frequently been found together, Brachionus chelonis must be considered as a good species. (ref. ID; 2328)
This species has long been treated until today by most taxonomists as subspecies (Kofoid 1908; Fadeew 1928; Wiszniewski 1953; Kutikova 1970) or variety (Voigt 1956; Rudescu 1960; Koste 1978) of B. quadridentatus. However, it has appeared in the Southwestern Islands of Japan quite independently from other forms of B. quadridentatus except for only a few cases, i.e. Kohama Jima, and Ishigaki Jima. In the morphology of the pectoral margin and foot opening this species is clearly deviated from all others under quadridentatus. Consequently, cluniorbicularis may be considered as a good species. While, isigakiensis differs from typical cluniorbicularis in having an undulated pectoral margin which more or less resembles that of durgae. (ref. ID; 2874)
Type locality
Ishigaki Jima site 2A. (ref. ID; 2874)
Measurements
Lorica length 180-200; widest part 70-80; width at the anterior extremities 100-110; elevation of pectoral margin 10; occipital median sinus 28-30 µm. (ref. ID; 2874)
Brachionus dichotomus was first described and figured by Shephard (1911: P1. XXII, Figs.3, 4) from waters at Templestowe and Black Rock, Victoria. Only Harring (1913: p.21) recognized the validity of the species. Ahlstrom (1940: p.164), in his revision of the genera Brachionus and Platyias, included the species as a probable synonym of B. falcatus Zacharias, 1898, nothing, however, 'If ... Shephard's description is accurate, Brachionus dichotomus is a distinct species'. This uncertainty led to the exclusion of B. dichotomus from the list compiled by Gillard (1948: p.210-211) of the known species of Brachionus. Voigt (1957: p.157) mentioned the species with the imperfectly described forms of the genus, giving a figure (Tab.72: Fig.24). B. dichotomus was absent from Ruttner-Kolisko's (1972, 1974) comprehensive and definitive work on the planktonic Rotatoria, and Koste (1978: p.83), on the basis of a literature search, found that the species was unheard of in the 66 years following its first description. (ref. ID; 3191)
Measurements
Total lorica length (including spines) 200-488; lorica length 84-140; lorica width 80-148; length of anteromedian spines 55-140; length of caudal spines 80-200; subitaneous egg 80-88/60-64 µm. (ref. ID; 3191)
The form of the lorica of this rotifer agrees fully with the type, shown by the deep insertion of the lateral antennae almost at the level of the top of the boundary of the ventral foot-opening, underlying which is the swollen lateral formation of the lorica, and the dorsal, somewhat domed plate over the foot-opening. This plate is described in Shephard's type description as follows: 'There is also at the posterior end, overhanging the bases of the spines, a projecting plate having a gentle outward curve in the centre, and a sweeping outwards at each side to form two short, acute points'. Such a configuration of the dorsal boundary of the foot-opening is not known in B. caudatus forms (Ahlstrom 1940). The lorica of new form reaches a total length (including spines) of only 145-180 µm. The anteromedian spines are short (18-28 µm). Whereas anterolateral spines as found in the f. type. are absent, rudimentary anterosubmedian spines are present. Such rudiments occasionally appear also in juveniles of B. dichotomus f. type. The lorica of the new form is 60-64 µm high. The dorsal plate is occasionally faceted. The asymmetric posteromedian spines are conspicuously short (30-36/40-45 µm). The subitaneous egg measures 68/48 µm. Juvenile individuals hatched from these reproductive bodies are distinctive in their appearance compared to f. type, individuals of an essentially corresponding age group. The above-described morphological taxonomic characteristics of the lorica show a close affinity with B. dichotomus dichotomus Shephard, 1911. However the dissimilar size of the subitaneous eggs and the form of the juvenile stage are indications of two genetically distinct population. Also, the lack of modification of the type species raises the question of the taxonomic rank of this new Brachionus form. It is proposed, in the absence of geographic isolation, in a syntope, to conclude that subspecific rank is appropriate. (ref. ID; 3191)
Comments
See Brachionus caudatus. (ref. ID; 3191)
Measurements
Total lorica length (including spines) 145-180; lorica length 85-100; lorica width 78-90; length of anteromedian spines 18-28; length of caudal spines 30-45; subitaneous egg 68/48 µm. (ref. ID; 3191)
Brachionus calyciflorus var. dimidiatus Bryce, 1931 (ref. ID; 1345, 1347, 2627) or 1954 (ref. ID; 3688); Brachionus pala var. dimidiatus Bryce, 1931 (ref. ID; 3688); Brachionus pala var. quartaria de Beauchamp, 1932 (ref. ID; 1345)
Descriptions
Lorica oval with 4 short anterior spines. Posterior and posterolateral spines absent. In some forms, anterior spines reduced to blunt projections. Resting eggs usually female body. (ref. ID; 1806)
It resembles dimidiatus quartarius de Beauchamp, 1932. But, differing from it in having right angled triangular lateralo-occipital spines, trapezoidal pectoral margin and features of caudal extremity. (ref. ID; 2874)
Sudzuki (1964, see ref. ID; 3114) states "the structure of the toes, especially claws is nevertheless peculiar and the difference from usual Brachionus is qualitative and suggests the use of the generic name Schizocerca for diversicornis. (ref. ID; 1929)
Descriptions
With four occipital spines, laterals longer than medians. Posterior spines two, unequal and divergent; the right spine usually longer. (ref. ID; 1805)
Four occipital spines, the laterals longer than the medians. Right posterior spine longer than the left. Toes characteristically with claws. (ref. ID; 1929)
With four occipital spines; the laterals longer than the medians. Two unequal and divergent posterior spines, the right spine usually long. (ref. ID; 2704)
Male: Male present. (ref. ID; 3066)
Quote from ref. ID; 3066
Measurements
Lorica length 202; maximum width 130; antero-lateral spines 78; right posterior spine 90; left posterior spine 38 µm. (ref. ID; 1804)
Total length 294; length of lorica 182; anterior lateral spines 42; posterior spines 14, 70; maximum width 126; length of toe 28 µm. (ref. ID; 1929)
Total length 360; maximum width 130; anterior occipital spines 75-80; right posterior spine 80; left posterior spine 40 µm. (ref. ID; 2704)
Length of ventral lorica 680 µm. (ref. ID; 2891)
Total length 258-430; dorsal lorica length (without spines) 195-220; width at the basis occipital lateral spines 70-129; widest part 130-150; anterior median sinus 10-18 wide, 20-22 deep; anterior lateral spines 60-100; caudal projection or protuberance 10-20 (left), 20-85 µm (right). (ref. ID; 3083)
It has some resemblance to B. angularis Gosse, but is distinctly smaller and has several characteristic features of its own. (ref. ID; 3217)
Brachionus donneri Brehm, 1951 (ref. ID; 1345, 2626 original paper) or 1950 (ref. ID; 2715) reported year? (ref. ID; 3019)
Comments
Brehm (1951) shows 6 blunt spines at the anterior dorsal margin and 4 blunt spines at the anterior ventral margin, whereas forms found in Sri Lanka have 6 blunt spines on both the ventral and dorsal aspects. The posterior projections of the lorica are club shaped and have a deep sinus between them. The projections from the side of lorica are also prominent. (ref. ID; 2715)
In the material from Grand Lake, Tonle Sap, Cambodia at 14 February 1951 I found this species. I prepared a description at a new species, but did not publish it at once. However shortly after that Brehm published his Brachionus donneri from Madras, Indien, 1951. My organisms resemble much the specimens seen by Brehm. I found them in my sample in considerable abundance. But the individuals from Cambodia are somewhat smaller than the organisms from India. The animals are very strongly flattened dorsoventrally. (ref. ID; 3019)
Measurements
Length of lorica 206; width at anterior end 170 µm. (ref. ID; 2715)
Total length of lorica 175-190; width, maximal 165-172; occipital border width 82-86; occipital sinus, depth 17; posterior sinus, length 57-62, width 30-35 µm. (ref. ID; 3019)
It resembles B. pterodinoides Rousselet and B. plicatilis Muller it differs from them in a few characters. It differs from B. pterodinoides by its mental margin with a median sinus, the foot opening flanked by anchor-shaped spines and by a well developed foot sheath. B. plicatilis differs from the present form in having the mental margin scalloped with four projections rounded at their edges, a lorica little compressed dorso-ventrally, a foot without sheath, and in having the posterior foot opening not covered by the dorsum. (ref. ID; 1929)
B. durgae is a relatively large Brachionus, that can be confused with B. urceolaris or, especially, B. pterodinoides. The species is diagnosed by the following characters: (1) It is large and has a relatively soft lorica; (2) The subdistal foot aperture is ventrally a deep fissure, and has a soft, rounded lobe dorsally; (3) The ventral margin of the head aperture is smoothly undulate, with a characteristically notched pair of median lobes; (4) Eggs are attached to the body by conspicuous, long attachment filaments. Anchor-shaped spines lateral of the foot (Dhanaphathi 1974) could not be observed in our African and Indian material, and are also reported absent in Sudzuki's (1992) "subspecies" B. durgae isigakiensis, the validity of which is rejected. A synonymy of B. durgae with B. pterodinoides, as opined by Sharma (1987), cannot be confirmed. There is doubt that the record of B. variabilis (Hempel, 1896) from the Orinoco River, Venezuela by Vasquez & Koste (1988) represents this species, judging from its accompanying figures. The description, drawing and photograph of B. moronensis Kuczynski, 1991 reveal a synonymy of the latter with B. durgae. (ref. ID; 2984)
Descriptions
Lorica smooth, nearly round, divided into dorsal and ventral plates and compressed dorso-ventrally, but body curved ventrally. Anterior dorsal margin with six saw-tooth like spines of nearly equal length, with a V-shaped sinus and not elevated towards the centre. Mental margin with projections with truncated edges and a short medium sinus. Lorica not stippled but anteriorly ridges present, marking the continuation of the frontal spines. Foot opening situated below the centre of the ventral plate, pear shaped and flanked by anchor shaped spines. Foot sheath developed. (ref. ID; 1929)
Redescription
Parthenogenetic female: Lorica stiff, widest in posterior half. Ventral and dorsal plates smooth, fused laterally and distally. Dorsal head aperture with a pair of relatively long median spines, separated by a deep U-shaped sinus, a pair of shorter intermediate and a pair of lateral spines Ventral head aperture margin smoothly undulated, with a medial sinus, a pair of notched median and smooth intermediate lobes and a pair of lateral sinuses. Apertures of the lateral antennae visible dorso-ventrally, near posterior third of lorica. Foot opening ventral, pear-shaped, anteriorly deep inverse V-shaped. Dorsally covered by a soft, rounded lobe. Foot annulated, retractile, ending in two conical toes. Trophi of the usual type in the genus. (ref. ID; 2984)
Parthenogenetic egg: (up to 3 per female) Elliptic, with soft shell, attached to the dorsum of the foot by long filaments. (ref. ID; 2984)
Male: Male unknown. (ref. ID; 2984)
Measurements
Total length 266; Maximum width 224; width at anterior margin 140; length of occipital spines 14; length of the anchor shaped spines flanking the foot opening 28 µm. (ref. ID; 1929)
Lorica length 266-283, width 220-250 µm. Head aperture width 140-165, dorsal antero-median spine length 28-36 µm. Parthenogenetic egg length 137-152, width 90-106 µm. (ref. ID; 2984)
This species is fundamentally identical with durgae Dhanapathi, 1974. It differs only in having 1) both lateral and intermediate spines curved inward at their tips and 2) four untrapezoidal margin and 3) lacking anchor shaped foot spines. B. durgae is demarked from pterodinoides Rousselet, 1913 (also Ahlstrom, P1.14, Fig.10 from Devils lake = Type locality) in the position of the foot opening, from westphali Carlin-Nilson, 1935 (Figs.8-9) from Mexico in the features of the pectoral margin. And, from both in the general shape of the lorica. (ref. ID; 2874)
Type locality
Ishigaki Jima site 2A. (ref. ID; 2874)
Measurements
Lorica length 270; widest part 220-250; width at the anterior extremities 140-150; elevation of pectoral margin 12; occipital median sinus 20-28 µm. (ref. ID; 2874)
Occipital margin with six spines; intermediates much longer and curved ventrally; medians and laterals shorter and of almost equal length. Posterior spines long, incurved and with widely separated bases. (ref. ID; 1805)
B. falcatus is not highly variable except for slight growth in the anterior and posterior spines. The anterior and posterior spine growths increased during May when water temperature was above 30 degrees C. Majority of the specimens had posterior spines bowed inwards as an adaptation for floatation. The anterior spine growth decreased during August, September and October months followed by the elongation of the lorica. The lorica was broader than longer during May. (ref. ID; 1939)
The anterior and posterior spines vary considerably. A form with very spines was found in large numbers from a river. This form with shorter spines may be a modification for running water existence since longer spines tend to entangle easily. (ref. ID; 2715)
Lorica composed of a dorsal and ventral plate and compressed dorso-ventrally. Anterior dorsal margin with six spines. The intermediates are much longer than the laterals and curved laterally outwards. Median spines equal to the lateral spines. (ref. ID; 2867)
Male: Male present. (ref. ID; 3069)
Measurements
Total length 340; maximum width 128; posterior spines 145 µm. (ref. ID; 1805)
Total length 289; length of lorica 125, width 125 µm. (ref. ID; 2251)
Total length 246; width 96; anterior lateral spines 12; anterior intermediate spine 69; anterior median spine 12 µm. River form; total length 213; width 114; anterior lateral spines 18; anterior intermediate spine 33; anterior median spine 15 µm. (ref. ID; 2715)
Total length 340; length of lorica 150; maximum width 160; length of antero-median spine 20; length of antero-intermediate spine 70; length of antero-lateral spine 20; length of posterior spine 120 µm. (ref. ID; 2867)
Total length (TL) 184-405; width at the basis occipital lateral spines 42-95; widest part 68-156; distance between caudal protuberances at the base 40-89; caudal projection or protuberance (CP) 78-190; CP/TL 0.34-0.79; thelytokous egg 88x70 µm. (ref. ID; 3083)
Total length 240-256-368 µm. (ref. ID; 3387)
Brachionus falcatus f. lyratus (ref. ID; 3069), var. lyratus Lammerman, 1908 (ref. ID; 1929) Lemmerman, 1908 (ref. ID; 3114) reported author and year? (ref. ID; 3292)
Descriptions
Anterior dorsal margin with six unequal spines. Intermediates very long and curved ventrally at their ends. Posterior spines very long, bent inwards and in some forms almost touch each other at their tips. Lorica stippled. (ref. ID; 1929)
Male: Male present. (ref. ID; 3069)
Measurements
Total length 210-266; Intermediate spine 42-70; posterior spine 70-84; maximum width 98-112; length of lorica 98-112 µm. (ref. ID; 1929)
Brachionus falcatus f. reductus Koste & Shiel, 1983 (ref. ID; 2759 original paper)
Descriptions
Very robust lorica of barrel-shaped outline. Anterior-, marginal- and medial spines as in type form. Submedial spines shortened in proportion to lorica. Caudal spines shortened but strongly developed. Surface of dorsal lorica with pearl-like structures. Pair of ridges begin at basis of submedian spines, run to height of lateral antennae. Ventral lorica flat and strong, detailed with a granulated pattern. (ref. ID; 2759)
Male: Male not recorded. (ref. ID; 2759)
Comments
This pantropical and pansubtropical species shows little variability in its habit. It is occasionally encountered in summer warmed eutrophic biotopes in Europe, particularly in Romania and the Caucasus. (ref. ID; 2759)
Measurements
Lorica length 100-280 including anterior and posterior spines; lorica width 80-164; subitaneous egg 80x60 to 100x72 µm. (ref. ID; 2759)
Characterized by stout, bent posterior spines with knee-like swellings on the inner sides of their bases. Four occipital spines; laterals of variable length but longer than the medians. (ref. ID; 1805)
Occipital margin with four spines; laterals longer than medians. Posterior spines stout, unequal, bent and with knee-like swellings on inner sides of these bases. (ref. ID; 2704)
Anterior intermediate spines missing. The antero-lateral are longer than the antero-median spines. Lorica terminates posteriorly in a pair of stout more or less equal spines and have no swellings at the base of these spines. (ref. ID; 2715)
Male: Male present. (ref. ID; 3065, 3114)
Quote from ref. ID; 3114
Egg: (ref. ID; 3064)
Quote from ref. ID; 3064
Measurements
Total length 220; maximum width 110 µm. (ref. ID; 1805)
Total length 275; maximum width 108; anterior width 78; anterolateral spines 40; posterior spines 110 µm. (ref. ID; 2704)
Total length 195; width 92; anterior median spines 10; anterior lateral spines 20; posterior spines 84 µm. (ref. ID; 2715)
Total length 99-226; width at the basis of occipital lateral spines 50-66; widest part 62-100; distance between caudal protuberances at the base 40-96; anterior median sinus 6-10 wide, 10-18 deep; anterior lateral spines 8-22; caudal projection or protuberance 16-106 (right), 0-98 (left) µm. (ref. ID; 3083)
Brachionus forficula f. minor Voronkov, 1913 (ref. ID; 3114) or Voronkow, 1913 (ref. ID; 3688) reported year? (ref. ID; 2622, 7859) reported author and year? (ref. ID; 3239), var. minor (Voronkov, 1913) (ref. ID; 1805)
Synonym
Brachionus havanensis var. Voronkow, 1915 (ref. ID; 3688)
Measurements
Total length 142; maximum width 72; posterior spines 49 µm. (ref. ID; 1805)
It differs from B. forficula var. keralaensis Nayar & Nair (1969) by the presence of knee like swellings for the posterior spines and by showing four occipital spines. (ref. ID; 1929)
Descriptions
Four occipital spines with lorica, posterior spines pustulated. Posterior spines bowed inwards with characteristic knee-like swelling at the inner side neat their base. (ref. ID; 1929)
Measurements
Total length 196; width of anterior margin 70; maximum width 98; length of lorica 98; posterior spines 84 µm. (ref. ID; 1929)
Lorica rather oval, narrowing posteriorly and terminating in two stout and very long spines. Anterior dorsal margin with six spines, laterals and medians long, intermediates very short. Laterals longest, usually divergent, occasionally parallel or slightly convergent. Anterior ventral margin somewhat elevated toward the center, with an U-shaped median sinus flanked on either side by a short spine-like process, lateral sinuosities present. Posterior spines usually longer than the rest of the lorica, curved dorsally, subequal, the left spine somewhat reduced. The posterior spines show a great variability in their shape in the preserved state, they may be straight and close together or divergent and bent at their extremities. (ref. ID; 775)
Posterior spines subequal; anterior lateral spines parallel to convergent; posterior spines more or less parallel and bent dorsally. (ref. ID; 2817)
Measurements
Total length 270-315; greatest width 92-101; anterior lateral spines 35-46; anterior intermediate spines 2-5; anterior median spines 22-25; posterior right spine 116-163; posterior left spine 107-148 µm. (ref. ID; 775)
At a glance B. huangi n. sp. is similar to B. diversicornis by its body shape. But it can hardly be confused with it by 1. the short submedianspines; 2. the symmetric stout caudal spines; 3. the wide caudal projection. (ref. ID; 7853)
Descriptions
Parthenogenetic female (male unkonwn): Lorica relatively elongate. Three pairs of apical spines, the lateral pair longer than others, the submtidanspines small but obvious. Caudal spines symmetric, stout and divergent. Caudal projection big and wide. Ventral apical margin nearly straight except a very small concave in the center. (ref. ID; 7853)
Distribution and ecology
Only known from type locality. At the time of sampling, temperature was at 10 degrees C and pH 6.0. (ref. ID; 7853)
Etymology
The species is named for Pof. Huang Xiangfei, Institute of Hydrobiology, Chinese Academy of Sciences, in recognition of his support and help during the study. (ref. ID; 7853)
Type locality
B. huangi was taken form Shiling Lake in the Yunnan Province on March 14, 1995. (ref. ID; 7853)
Material examined
Holotype (ROT-010) and two paratypes (ROT-011) are deposited in the Institute of Hydrobiology, Chinese Academy of Sciences. (ref. ID; 7853)
Brachionus ibericus Ciros-Perez, Gomez & Serra, 2001 (ref. ID; 6876 original paper) reported author and year? (ref. ID; 4441)
Differential diagnosis
Brachionus ibericus n. sp. can be distinguished from the two other species belonging to the B. plicatilis complex in three ways. First, the anterior-dorsal spine pattern: the three pair of spines are similar in length; the median spine is shaped like an equilateral triangle, in contrast to both B. plicatilis and B. rotundiformis. Second, by the shape and surface topography of resting egg which is ovoid in shape, with a characteristic rough surface pattern of anastomosing wavy ridges uniform in size, and with pores densely distributed on the entire egg surface. The egg shape differs from that described by Munuswamy et al. (Munuswamy et al. 1996) for B. rotundiformis. Third, the mode of carrying the resting eggs is different. The resting eggs remain inside the lorica (one single resting egg produced per female). (ref. ID; 6876)
Descriptions
Parthenogenetic female: Lorica relatively soft and flexible, ovoid shaped head aperture relatively wide. Lorica surface smooth. Anterior dorsal margin with six pointed, triangular spines, all similar in size, three on each side of a V-shaped sinus. Spine arrangement is constant in all analysed clones; the inner spines the most prominent, the external ones least developed. Median spines shaped like and equilateral triangular. Anterior ventral margin with two pairs of lobules flanking a narrow sinus; the external lobules slightly wider than the inner ones. Lateral antennae located slightly posterior to the lorica midpoint. Foot aperture sub-terminal, on ventral plate. (ref. ID; 6876)
Trophi: Malleate and symmetrical. Fulcrum short. Rami similar to a rectangular tetrahedron, with a ventral, flat surface; anterior processi soft, lamellate. Unci plate-like, with five solid ridges having four teeth-like structures proximally. Subuncus brush-like, consisting of several rows of small teeth or spines located at the inner side of the proximal ends of the unci. Manubria flattened plate-like structures, highly twisted and bent distally, with three opened proximal cavities. (ref. ID; 6876)
Resting egg: A single resting egg carried within the lorica. Mictic egg ovoid, slightly flattened on both sides. Operculum located in a slight depression, defining a skullcap-like structure on one end of the egg. Surface topography showing and anastomosing pattern of granulated, wavy ridges, uniform in size, pores densely distributed on both the ridges and the depressions. (ref. ID; 6876)
Comments
Brachionus ibericus n. sp. has been previously referred as B. rotundiformis SM (Gomez et al., 1995). The differentiation between this and the other two sibling species belonging to the B. plicatilis complex is based on genetic markers, assortative mating behaviour, etc. For a morphological comparison, see the redescription of the both B. plicatilis Muller and B. rotundiformis Tschugunoff below.
According to the Principle of Priority of the International Code of Zoological Nomenclature, and following Segers' criteria used with B. plicatilis (Segers, 1995), the oldest available name applying to a taxon should be used for a stable nomenclature. Accordingly, one of the junior synonyms of B. plicatilis could have been used for the SM-type animals. Unfortunately, as Segers pointed out, no type material is available for any of those names and the original descriptions do not permit recognition of the taxa. However, when comparing with some of the published drawings a resemblance between B. ibericus n. sp. and B. plicatilis f. longicornis Fadeev, 1925 can be observed [see (Koste, 1978), T.9, Figure 1b; (Koste, 1980), p.152, Figure 4]. Nevertheless, this superficial similarity with B. plicatilis f. longicornis is insufficient to establish that this taxa and B. ibericus n. sp. are the same species, given that we are splitting species on very narrow morphological grounds that would not necessarily be reproduced in others' drawings. So, we prefer to use a new specific-name for our SM-type animals. Another reason to disregard using this nominal taxa (i.e. B. longicornis) is because there is evidence (Ortells et al. 2000; Gomez unpublished data; Ciros-Perez, unpublished data) that more genetically and morphologically distinct species (different to the clones analysed here) exist with a morphology close to the SM-type 'B. plicatilis'. So, the identity of B. plicatilis f. longicornis may be different from our Spanish animals, since very similar species can occur in a relatively reduced geographic region. (ref. ID; 6876)
Etymology
The species is named after the Iberian Peninsula. Its name derives from its ancient inhabitants whom the Greeks called Iberians, probably after the Ebro (Iberus) river that flows into the Mediterranean Sea close to the type locality. (ref. ID; 6876)
Type locality
Poza Sur is a man-made shallow pond (maximum size about 30 m long, 7 m wide and maximum depth in winter about 1.5 m), located in the Prat de Cabanes-Torreblanca Marsh (Castellon, Spain: 40 degrees 10'04"N, 0 degrees 10'57"E), a brackish water area next to the coast. (ref. ID; 6876)
Distribution and ecology
Brachionus ibericus n. sp. is known from several coastal ponds, lagoons and marshes located in Eastern Spain (Ortells et al. 2000), that include three ponds in Prat de Cabanes-Torreblanca Marsh [Poza Sur, Poza Norte and Canal Central, see (Gomez et al. 1995)], Estany d'en Turies (Parc Natural dels Aiguamolls de l'Ampurda), Laguna de San Lorenzo, El Basset de l'Altet, and two ponds (Charca Sur and Charca Ponient) in El Hondo de Elche Natural Park. These habitats vary from oligohaline to euryhaline, some of them are temporary while others are permanent [see (Ortells et al. 2000) for a detailed description and location of each site]. The spatial and temporal distribution of B. ibericus n. sp. in Cabanes-Torreblanca Marsh (type locality) has been well characterized (Gomez et al. 1995; Ciros-Perez, unpublished data). This species occurs at medium to high salinities (from 8 to 50 g l-1) and at high temperatures (>15 degrees C) during spring and summer. It has been observed co-occurring for relatively long periods (ca. 4 months) with one, or with both other sibling species of the B. plicatilis complex (i.e., B. plicatilis s.s and B. rotundiformis), as well as with other congeners (B. urceolaris). It has been observed in other waterbodies (i.e. Laguna de Almenara, and two ponds at El Hondo de Elche Natural Park) co-occurring with B. angularis, B. calyciflorus, B. quadridentatus, B. bidentatus and B. leydigi (Ortells, personal communication). The zooplankton assemblage accompanying the new species in Cabanes-Torreblanca Marsh also included some other monogonont rotifers (e.g. Notholca salina, N. marina, Colurella salina, C. dicentra, Lecane grandis, Synchaeta cecilia valentina, S. cf. oblonga, Encentrum marinum, Testudinella cf. parva and T. obscura) and a copepod (Diacyclops bicuspidatus odessanus). (ref. ID; 6876)
Material examined
Holotype: A parthenogenetic female, taken from a clonal population (strain SM2) maintained in the rotifer culture collection at the Institut Cavanilles de Biodiversitat i Biologia Evolutiva, University of Valencia (ICBIBE-UV), Spain, originally founded from a single amictic female collected in Cabanes-Torreblanca Marsh, May 6, 1993 (Gomez et al. 1995), was fixed (95%) and preserved (70%, with a drop of glycerine) with ethanol; vial deposited in the Natural History Museum (NHM: London, UK); catalogue number: NHM-2000.2929. (ref. ID; 6876)
Paratypes: Thirty parthenogenetic females belonging to each of the strains SM2 (collection data as holotype), SM5 (collected May 27, 1993) and SM11 (collected September 17, 1992), originated from the type locality. Specimens were fixed and preserved as the holotype. Vials deposited in the NHM; catalogue numbers: NHM-2000.2930-2959, NHM-2000.2960-2989 and NHM-2000.2990-3019. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain SM2) preserved with 70% ethanol into a vial, both deposited in the Academy of Natural Sciences (ANS; Philadelphia, USA); catalogue numbers: ANSP RO-1046 and RO-1049. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain SM2) preserved with 70% ethanol into a vial, both deposited in the National Museum of Natural History (NMNH; Washington, USA); catalogue numbers: USNM 189272-189273. (ref. ID; 6876)
Further material examined: Many more specimens, amictic and mictic females (entire, trophi and resting eggs), and males obtained from the experimental and stock cultures belonging to strains SM2, SM5 and SM11. Six trophi as SEM preparations are deposited at ICBIBE-UV. All clones are currently maintained the rotifer culture collection at ICBIBE-UV. (ref. ID; 6876)
Measurements
(Range and, in parenthesis, mean+/-SE; in µm) of adult (48+/-3 hr old) animals culture at 23 degrees C, 12 g l-1 salinity.
Female lorica length, 175.5-220.0(193.5+/-2.5); width, 126-163.0(144.5+/-2.5); head aperture, 84.0-113.5(99.0+/-2.5); depth of dorsal sinus, 18-25(21+/-1); length of dorsal anterior spine 2 (median), 12-22(16+/-1); length of dorsal-anterior spine 3 (external), 12-21(16+/-1). Torphi length, 30.6-31.3(30.9+/-0.2); fulcrum length, 6.4-7.9(7.2+/-0.4); manubrium length, 33.9-35.0(34.8+/-0.4); rami width, 31.8-34.0(32.9+/-0.6); uncus length, 19.0-20.9(20.4+/-0.4). Resting egg length, 128.3-137.2(132.3+/-2.6); width, 90.3-93.5(91.6+/-1.0). Male length, 96.5-116.0(109.0+/-2.5); width 59.5-66.5(62.0+/-2.5). (ref. ID; 6876)
A rigid, pear-shaped lorica with a vaulted ventral lorica plate on the lower third. Flat dorsal lorica plate present. Dorsal anterior rim terminates with 2 small inward-curving blunt spines, separated by a small circular aperture; other projections are missing. Ventral lorica margin almost straight, but medially weakly curved, strengthened and bulging on the rim. 4 ventral ridges lead outwards from the rim in the direction of the median ventral lorica. The raised, dorsally displaced foot opening surrounded by cuticular membranes, forming a caudal, paired tongue-shaped projection. It is placed balcony-fashion upon the, from here, elongated dorsal lorica margin. Lorica margin developed from 2 bulging, blunt spines directed inwards and upwards under the foot-opening, forming a hemispherical indentation. At this point the ventral lorica margin shows only one narrow cleft. Lorica surface totally granulated and, both dorsally and ventrally in the lower region, strongly studded with short, thorny protruberances. Ventral lorica shows paired, marginal longish triangular facets, separated by approximately vertical cuticular ridged ribs. Dorsal lorica characterized, particularly in the central region, by cuticular ribs which follow the contour of the lorica. They swing out laterally to their highest point at the greatest width of the lorica, and also parallel the lorica rim to the caudal blunt spines. Lateral antennae located on the margin in approximately the mid-lorica. (ref. ID; 2891)
Comments
The new species apparently belongs to the Formenkreis angularis-caudatus, suggested by the shape of the median, short anterior margin spines and the reduction of the laterals and sublaterals. However, until now, only forms with a caudal, ventrally located foot-opening and a mostly weakly structured ventral lorica have been placed in this Brachionus group. The characteristic position of the lateral antennae, the dorsally situated, raised foot-opening, the facetting of the ventral lorica surface, and the hemispherical indentation under the foot-opening between the blunt, bulging caudal lorica spines clearly characterize Brachionus keikoa as a bona fide species. On the basis of present knowledge it is possibly an endemic of these waters of Notogaea. (ref. ID; 2891)
Etymology
This species is named for keiko Sudzuki, wife of the eminent Japanese rotifer taxonomist, Professor Dr Minoru Sudzuki, Biology Laboratory, Nihon Daigaku, Omiya-shi, Saitama-ken, Japan, in gratitude for a long friendship and mutual cooperation. (ref. ID; 2891)
Anterior spines are all curved. The inner two spines curve outward, the intermediates and laterals usually curve inwards. The posterior end of the lorica usually broader than the anterior end. The three spines surrounding the foot opening are prominent. (ref. ID; 2715)
Lorica firm, nearly square in shape, divided into a dorsal, a ventral, and a basal plate. Anterior dorsal margin with six spines, nearly equal in length in some forms, though the medians are a little longer than the other pairs and curve somewhat ventrally. Mental margin rigid, undulate, raised toward the center. Small spines usually present at the junction of dorsal and basal plates. Foot opening large, nearly circular or club-shaped ventrally. (ref. ID; 3180)
Measurements
Total length 220; maximum width 165 µm. (ref. ID; 1805)
Total length 280 µm. (ref. ID; 2715)
Lorica shape resembles B. lyratus Shephard, 1911, but at anterior dorsal margin of head opening only short inwardly curving median spines present; intermediate spines absent. Lateral spine relatively long, blunt, curved towards ventral plate. Dorsal surface facetted, with caudal median projection overlapping foot-opening. Club-shaped posterior projections curve outwards as in type, but covered with minute papillae. Ventral plate ornamentation resembles B. pinneenaus Koste & Shiel, 1983, but caudally a long ventral facet is lacking. Lorica granulated, more strongly on the dorsal plate. (ref. ID; 2886)
Comments
The new taxon belongs to the endemic and morphologically distinct Brachionus group comprising B. lyratus Shephard, 1911, B. keikoa Koste, 1979 and B. pinneenaus Koste & Shiel, 1983. These taxa can readily be separated from the Brachionus angularis group after Ahlstrom (1940). Another distinct morph has been found recently in material from N.S.W. Until this population, is described, and the extent of variation in the above Australian endemics is fully detailed, the Tasmanian material is regarded as a subspecies. The need for continued use of trinomials in rotifer systemtics, which still is founded mostly on morphological and anatomical characteristics, is discussed by Koste & Shiel 1987. (ref. ID; 2886)
Type locality
Turbid stock dam 200 m east of Karanja, east side of Strathgordon road. Also present in a second dam about 45 m west. Neither dam had emergent vegetation. 19.5-22.0 degrees C, pH 4.0-6.2, 228-242 µS cm-1. (ref. ID; 2886)
This species resembles well lyratus described and figured by Shephard (1911, Fig.5) in the general shape of the lorica, especially provided with obliterated intermediate spines. But, it differs from lyratus Shephard in following insignificant characters, i.e. 1) direction of both occipital median spines and caudal projection, 2) lacking of occipital lateral spines and 3) the features of pectoral margin. While, yonaguniensis differs from caudatus f. vulgatus Koste (1979, Fig.12, without photo proof!), which was treated with lyratus by his coworker, in absence of occipital lateral spines, from pinneenaus Koste et al. (1983, Fig.2) in the direction of caudal projections besides the outline of occipital margin, further from tasmaniensis (Koste et al., 1886, Fig.2), 1) in the direction of caudal projections, 2) presence of intermediate spines and 3) wanting of ventrally curved lateral spines although the photo proof is missing again. (ref. ID; 2874)
Brachionus morondavaesis Sudzuki, 1998 (ref. ID; 5008 original paper) reported author and year? (ref. ID; 2261)
Descriptions
This species is allied with angularis in wanting both lateral and intermedian spines on the occipital margin, easily distinguishable, however, in having knobbs on the intermedian region of the occipital margin. (ref. ID; 5008)
Type locality
A pond Korozoma Banimena, Morondava, Madagascar. (ref. ID; 5008)
Measurements
Lorica without spines 100-110 µm, maximum width 80 µm. Median sinus 11 µm. Posterior projection 9 µm. (ref. ID; 5008)
Lorica rather firm, oval, [greatest width]/[total length] ratio 0.68-0.76, the greatest width is a little below the middle of the lorica. Anterior dorsal margin with six short spines of nearly equal length, medians usually slightly longer than laterals and intermediates. Anterior ventral margin rigid, with a V-shaped central sinus. Lorica narrows toward the posterior end, without posterior spines. Foot opening with a small V-shaped ventral aperture. Dorsally a shield-like, spatulate projection extends over the foot opening, it is sub-square to rectangular in shape, thin and very transparent, and overhangs the ventral posterior end of the lorica. Lorica smooth or slightly stippled. This species is closely related to B. urceolaris, but it differs in the characteristics of the foot opening and in the different side view, in B. moronensis lacks the dorsal border of the lorica that is usually present in B. urceolaris; the anterior spines are shorter and the lorica more ovated than in B. urceolaris. B. moronensis is easily distinguishable from B. variablis lacking posterior spines by the posterior projection broader and larger, overhanging the posterior ventral portion of the lorica, and by the shorter anterior spines. This species may be readily recognized by the peculiar posterior spatulate projection. (ref. ID; 775)
Measurements
Total length 214-277; greatest width 142-195; anterior lateral spines 9-12; anterior intermediate spines 7-9; anterior median spines 11-16; width of the posterior dorsal projection 24-33; subitaneous egg 126x82 µm. (ref. ID; 775)
Lorica more or less rounded. Anterior spines are narrow, pointed and short with a short strengthening ridge. Median sinus prominent. Juvenile forms of B. nilsoni were found in some samples. They were smaller and the spines have not developed well except for the antero-medians. (ref. ID; 2715)
B. niwati is close to B. budapestinensis Daday. It differs by (1) unequal antero-dorsal spines, (2) lateral antero-dorsal spines directed outwards, (3) lorica relatively soft. The trophi structure of B. niwati and B. budapestinensis deviate from that of all other Brachionus, it, in fact, more closely resembles that of Plationus. Their foot, on the other hand, is as in Brachionus, not pseudosegmented as in Plationus. (ref. ID; 1831)
Descriptions
Parthenogenetic female: Lorica relatively soft, flexible. Dorsal and ventral plate fused laterally and posteriorly. Anterior dorsal margin with pair of large, elongate median spines, and pair of short, triangular lateral spines, these directed outwards. Anterior ventral margin broadly bilobate. Small spicules present on ventral anterior margin and dorsal median sinus. Short sublongitudinal ridges anteriorly on ventral and dorsal plates. Lateral antennas postero-dorsally. Foot aperture subterminally on ventral plate. (ref. ID; 1831)
The species is named after Dr. Niwat Sanoamuang, Khon Kaen University, who collected the species, and in appreciation of his help in the field. (ref. ID; 1831)
Brachionus variabilis var. novae-zelandiae Morris, 1913 (ref. ID; 1345)
Comments
This species is a synonym of Brachionus variabilis, as some examples of this latter have been found by de Beauchamp (1947, p.42) and Murray (cited by de Beauchamp 1947), with an almost atrophied dorsal tongue of the foot-opening, which makes them intermediate with Brachionus novae-zelandiae. A geographical cline might perhaps be established. (ref. ID; 2328)
Lorica rectangular, may be slightly widened at the posterior end. Anterior margins with ten pronounced spines, dorsal medians longest and curved ventrally. Posterior lateral and posterior median spines relatively short. Lorica slightly areolated or tuberculate. (ref. ID; 775)
B. patulus is a very common rotifer and varies considerably in the development of spines. Some specimens have long posterior spines, both lateral and median. However, in most specimens the posterior median spines are shorter than the lateral and are asymmetrical. This species is considered to be cosmopolitan. (ref. ID; 2715)
Lorica stiff and well developed, broader than long with ten anterior spines, four projecting from the dorsal side, four from ventral side and two from lateral. Four posterior spines of unequal size. Some authors have designated this species as Platyias patulus (Green 1960; Arora 1966). (ref. ID; 2867)
Both anterior dorsal and ventral margins with pronounced spines. Ten anterior spines present: occipital median spines longest, curve over head ventrally; pectoral medians shortest, straight; intermediates on both margins and laterals about equal in length. Posteriorly the lorica narrows but little, if at all, and terminates in two stout spines, usually very short. Foot opening bounded by two spines. (ref. ID; 3180)
Measurements
Total length 158-242; greatest width 105-150; anterior median spines (dorsal) 37-48 µm. (ref. ID; 775)
Total length 190; maximum width 138 µm. (ref. ID; 2704)
Total length 255-275 µm. (ref. ID; 2715)
Total length 170; length of lorica 110; maximum width 100 µm. (ref. ID; 2867)
Lorica rectangular, widening toward the posterior end, [width at the tips of the anterior lateral spines]/[greatest width] ratio 0.75-0.76. Anterior margins with ten pronounced spines, dorsal medians and dorsal intermediates curved ventrally. Posterior spines stout and greatly elongated. (ref. ID; 775)
B. p. macracanths differs from B. patulus only in the size of the posterior spines. The typical patulus has a median posterior spine 33-37 µm long and lateral spines 45-51 µm long. (ref. ID; 1847)
Measurements
Total length 320; greatest width 170; width at the tips of the anterior lateral spines 126; anterior lateral spines (dorsal) 41; anterior median spines (dorsal) 47; posterior lateral spines (longest) 129; posterior median spines (longest) 133 µm. (ref. ID; 775)
A rigid, pear-shaped lorica. Dorsal and ventral plate distinctly patterned. Dorsal apical rim of lorica with two small incurving blunt medial spines and short marginal projections. Ventral anterior rim with medial indentation flanked by reinforced ribs. Apical opening and lorica surface coarsely granulated. Foot-opening dorsally low, ventrally of normal form. Caudal spines end in broad knob. Dorsal lorica pattern: Medianfrontal panel free. Below this, one trapezoid anteromedian and one pentagonal mesomedian panel, both flanked by two pairs of symmetrical lateral panels. Two low, broad panels above the foot opening, the caudal border of the last indistinct. Ventral lorica pattern: A long, narrow vase-shaped mesomedian panel abuts on a narrow quadrangular facet, the posterior margins of which continue as semicircular cuticular ribs above the foot-opening. Two symmetrical triangular and six symmetrical lateral facets. Lateral antennae neat end of border between posteromedian panels. (ref. ID; 1417)
Comments
The lorica morphology of the new species distinguishes it as a member of the diverse Brachionus angularis group, after Ahlstrom (1940), containing populations with variably facetted loricas, lightly or coarsely stippled. Ahlstrom differentiated the angularis group from the B. dolabratus group (pseudodolabratus-dolabratus) on the basis of lateral protuberances. These protrusions of the lorica are below the lateral antennae. In Australia a third morphologically distinct species group is distinguished, comprising the previously described B. lyratus Shephard, 1911, and B. keikoa Koste, 1979, and to which B. pinneenaus n. sp. belongs. These taxa are characterised by an externally strongly developed, coarsely granulated lorica. Moreover, B. keikoa and the new species exhibit a peculiar lorica outline, with a distinct constriction of the anterior third of the lorica, followed by a synchronous broadening of the remaining body section. The rounding-off of the lorica is distinctive. The ridge-like ribs strongly expressed on the upper ventral lorica as far as the lateral panels are hitherto unobserved in B. angularis populations. Australian B. angularis and B. lyratus are described by Koste (1979). (ref. ID; 1417)
Etymology
"pinneena" is an Aboriginal term for a good place to catch water and store it for future needs (Read 1977). (ref. ID; 1417)
Type locality
Creek bed 25 km north of Cue, W.A. (27 degrees 16'S/118 degrees 00'E). (ref. ID; 1417)
Brachionus plicatilis Muller differs from the other two sibling species in the following ways. First, its anterior-dorsal spine pattern: three pairs of spines, all of them similar in length; the inner and outer spines roughly triangular with a wide base; median spine triangular in shape, but with a sigmoid outer margin. Second, shape and surface topography of resting eggs. Resting egg ovoid, with a fairly smooth surface with relatively few pores distributed on the entire egg surface. Surface arrangement differs from the description for B. plicatilis given in Munuswamy et al. (Munuswamy et al. 1996). Third, body size is larger than B. ibericus n. sp. and B. rotundiformis. (ref. ID; 6876)
Descriptions
Lorica six broad-based, acutely pointed and saw-toothed occipital spines. Mental edge four lobed. (ref. ID; 1805)
Lorica not firm, oval, not sharply separated into a dorsal and ventral plate. Anterior dorsal margin with six, broad-based, saw-tooth spines. Ventral margin separated into four lobes or very broad and blunt spines. Lorica posteriorly rounded, without spines. Brackish or saltwater species, usually in littoral regions. (ref. ID; 4594)
Parthenogenetic female: Lorica soft, pear-like shape. Dorsal and ventral plates fused laterally and posteriorly. Lorica surface coarsely smooth or dotted. Anterior dorsal margin with three pairs of spines flanking the U-shaped sinus; all spines roughly triangular similar in length, with wide base and relatively sharp apices; outer margin of median spines sigmoid with sharp apexes. Anterior ventral margin of the lorica with two pairs of rounded lobules flanking a slender sinus; outer lobules having a wider (about 1.5 times) base than the inner ones. Lateral antennae medially located. Foot aperture sub-terminal, on ventral plate. (ref. ID; 6876)
Trophi: Malleate and symmetrical. Morphology generally according to the description by Kleinow et al. (Kleinow et al. 1990). Fulcrum short and hollow, shaped like a truncated cone. Rami roughly rectangular-tetrahedron in shape, with a ventral flat surface; anterior processes soft and lamellate. Unci plate-like, with six or seven solid ridges; ridges having five teeth-like structures [four in the description by (Kleinow et al. 1990)] decreasing in size toward the anterior end, these structures followed by a flattened molar-like structure (the last ridge tip, or as a result of the fusion of the last two). All unci teeth arranged in the same plane except the most dorsal one of the right uncus; right uncus slightly directed to the inner side. Subuncus brush-like. Manubria flattened, highly twisted and bent distally, plate-like, nearly triangular shaped; three proximal cavities opened. (ref. ID; 6876)
Resting egg: Attached to the posterior part of the lorica when carried. Resting egg oval, slightly flattened on both sides. Operculum located in a scar-like depression at one end of the egg. Surface fairly rough with relatively few pores distributed on the entire egg surface. (ref. ID; 6876)
Designation of neotype
Since it has been established that no type material of B. plicatilis is available, and because we could not obtain topotypical material or isolate this taxon from the type locality (Denmark) to compare it genetically and morphologically with our Spanish clones, we decided to assign our B. plicatilis strains as neotype material. This decision was also taken considering that this morphospecies [sensu (Segers 1995)] seems to be a group of at least two different species (Gomez et al. 1998; Ortells et al. 2000), which reveals that this taxon is in fact a species complex. This redescription allows us to appropriately compare among our three sibling species. Deposit of reference material in public collections would permit further comparative research (i.e., morphology, genetics) that should clarify the actual status of this taxon. (ref. ID; 6876)
Comments
Recently, Segers (Segers, 1995) suggested that B. plicatilis Muller is the correct name for the so-called B. plicatilis L-type, which can be morphologically distinguished from the S-type or B. rotundiformis Tschugunoff. Based on morphological comparisons, several synonyms have been recorded for this taxon, that includes B. muelleri Ehrenberg, B. hepatotomus Gosse, B. plicatilis asplanchnoides Charin, B. plicatilis longicornis Fadeev and B. orientalis Rodewald. However, this B. plicatilis [sensu (Segers 1995)] is more diverse than previously thought (Gomez et al. 2000, 2001; Ortells et al. 2000; Rong et al. 1998), and deep genetic divergence has been reported within this taxon. As a result, we cannot assess, for the time being, the identity of all the nominal taxa presently listed as synonyms of B. plicatilis Muller without a careful and detailed analysis. The original description (i.e. published drawing) of B. plicatilis by O.F. Muller (Muller 1786; Koste and Hollowday 1993), that correspond to the so-called B. plicatilis plicatilis by Koste [(Koste, 1978); Plate 9, Figure 1c,f), is in good agreement with the morphology of our animals. But since no type material is available for comparison, we decided to redescribe this taxon from our Spanish material, in order to establish a base for enabling easier further comparative research that should clarify the identity of those synonyms and species inquirendae listed by Segers (Segers 1995). (ref. ID; 6876)
Distribution and ecology
B. plicatilis Muller has been found inhabiting several brackish and saline ponds, lagoons, lakes and marshes in the central, southern and eastern regions of the Iberian Peninsula, which are distributed five endorheic basins and in the coastal plain [see the so-called 'cluster A' in (Ortells et al. 2000; Gomez, et al. 2000)]. These habitats vary from oligohaline to euryhaline (3-55 g l-1), some of them are temporary while others are permanent. (ref. ID; 6876)
Material examined
Neotype: A parthenogenetic female, from a clonal population (strain L1) maintained in the rotifer culture collection at the ICBIBE-UV, originally founded from a single amictic female collected in Prat de Cabanes-Torreblanca Marsh, October 8, 1992 (Gomez et al. 1995). Ethanol fixed (95%), and preserved (ethanol 70%) with a drop of glycerine, vial deposited in the NHM (London, UK); catalogue number: NHM-2000.3020. (ref. ID; 6876)
Further material examined: Many more specimens, amictic and mictic females and males obtained from the experimental and stock cultures belonging of strains L1, L2 and L4. Thirty parthenogenetic females belonging of each of the strains L1 (collection data as neotype), L2 (collected November 2, 1992) and L4 (collected November 22, 1992), from the neotype locality. Specimens fixed and preserved as the neotype. Vials deposited in the NHM; catalogue numbers: NHM-2000.3021-3050, NHM-2000.3051-3080 and NHM-2000.3081-3110. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain L1) preserved with 70% ethanol into a vial, both deposited in the ANS (Philadelphia, USA); catalogue numbers: ANSP RO-1044 and RO-1047. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain L1) preserved with 70% ethanol into a vial, both deposited in the NMNH (Washington, USA); catalogue numbers: USNM189274-189275. Six trophi as SEM preparations, deposited at ICBIBE-UV. All clones are currently maintained in the rotifer culture collection at ICBIBE-UV. (ref. ID; 6876)
Measurements
Total length 170; maximum width 130 µm. (ref. ID; 1805)
Length 181; width 140; anterior spines 28 µm. (ref. ID; 2277)
Total length 180-250; width 140-200 µm. (ref. ID; 4594)
(Range and, in parenthesis, mean+/-SE; in µm) of adult (48+/-3 hr) animals cultured at 23 degrees C, 12 g l-1 salinity: Female lorica length, 274.0-341.0(299.0+/-2.5); width, 200.0-269.0(225.5+/-2.5); head aperture, 121.0-155.5(144.0+/-2.5); depth of dorsal sinus, 22-36(28+/-1); length of dorsal anterior spine 2 (median), 11-20(15+/-1); length of dorsal-anterior spine 3 (external), 12-26(17+/-1). Trophi length, 42.3-45.7(43.7+/-0.7); fulcrum length, 10.6-13.1(11.9+/-0.4); manubrium length 38.2-45.2(42.9+/-0.7); rami width, 39.1-42.2(40.8+/-0.5); uncus length, 22.0-26.0(24.0+/-0.5). Resting egg length, 134.2-139.9(137.0+/-2.8); width, 99.5-102.0(100.8+/-1.2). Male length, 121.0-141.0(130.5+/-2.5); width, 70.0-84.0(82.0+/-2.5). (ref. ID; 6876)
Greatly elongated transparent lorica. Surface unstructured. Anterior spines much reduced. Anterior border of ventral lorica with four short, flat, tongue-like projections. Posterior lorica margin tapered and rounded. Foot-opening terminal, lowered ventrally. Dorsal lateral antennae approximately level with mid-lorica. Ratio lorica length: width approximately 2:1. (ref. ID; 2758)
Comments
In the population examined, all adult females had an extraordinary large lorica, corresponding in appearance to that of B. plicatilis f. decemcornis Fadeev, 1925. The latter has a different foot-opening (see Koste 1978) and is smaller. Hauer (1925) describes an elongated form from Bad Oldesloe with a cross-sectioned lorica length of only 260 µm. A lorica of approximately corresponding outlines was figured by Ahlstrom (1940) with a length of 275 µm and a greatest width 210 µm. Neither of these is in accord with the Australian find. The greatest lorica length known to date is 315 µm. It is apparent that the new spp. population has arisen in Lake Colongulac in response to specific ecological pecularities of the habitat. (ref. ID; 2758)
The lorica of the "spatiosus" specimens was distinctly stouter and much less prone to distortion than in the undoubted "plicatilis" individuals. In most cases the former had a distinctly dark tint, arising possibly from the osmic acid used to kill them, but suggesting, at least, that there was greater thickness of "shell" to be affected, and it was certainly the case that the "spatiosus" specimens were much more symmetrical. In view of the similarity of the anterior edge of the ventral plate of the lorica, the Bryce thinks that Harring was justified in assigning the "spatiosus" form to the species B. plicatilis, but that it is inadvisable and tending to confusion if well-marked varieties are not allowed to retain some distinctive name. For this reason this form is listed under the style of a distinct and recognizable variety. In the genus Brachionus the form of the anterior edge of the ventral plate seems to be a much more reliable guide to specific identity than characters afforded by the dorsal plate, which are particularly unstable. (ref. ID; 3217)
Lorica firm, globose, circular to subcircular in outline, [greatest width]/[total length] ratio 0.80-0.95, the greatest width is at the middle of the lorica. Basal plate present. Anterior dorsal margin with six spines, laterals longest but curved ventrally, occasionally very much so. Medians longer than intermediates and divided by a U-shaped sinus. Median and intermediate spines bending somewhat ventrally. Anterior ventral margin concave, without sinus. Postero-lateral spines absent. Foot opening with projecting sheath flanked by an bluntly pointed process at either side. Lorica smooth. B. postcurvatus belongs to the 'Formekreis' quadridentatus-bidentatus (Koste, 1978). It shows comparative similarity to B. bidentatus lacking posterior spines ('inermis' form), but differs in the shape of the anterior lateral spines, in the markedly concave anterior ventral margin and in having a more globose lorica, about circular in outline. B. postcurvatus and B. bidentatus 'f. inermis' co-occured in the same collections, but any evidence of intergradation was detected. The marginal spines of B. postcurvatus may show a false appearance of being obliterate in dorsal view, and the lorica has thence a resemblance to B. angularis. (ref. ID; 775)
This species is very peculiar in possessing 1) caudal trapezoidal extension as is found only in B. kasadensis Sudzuki, 1976, which is provided with no occipital spines but medians, 2) occipital intermediate spines obliterated, 3) pectoral elevation is very high and a big V-shaped sinus present just as the case of both ruben and variabilis. At this point, this species is different from nilsoni Ahlstrom, 1940. (ref. ID; 2874)
Type locality
Yonaguni Jima site 1B. (ref. ID; 2874)
Measurements
Lorica length 102; widest part 78; occipital median sinus 12; occipital intermediate sinus less than 3; elevation of pectoral margin 12; caudal extension 12x18 µm. (ref. ID; 2874)
The lorica is nearly circular in shape, greatly compressed and flattened dorso-ventrally, and possesses a foot-opening situated just below the middle on the ventral plate, a most unusual situation for a Brachionus, but usual in Pterodina. The dorsal plate of the lorica is greatly extended posteriorly beyond the foot-opening, and under this projecting cover the eggs are carried. The lorica is smooth except anteriorly, where six small ridges mark the continuation of the six frontal spines. The mental edge is a nearly straight line and without indentation. As far as could be made out in the few preserved specimens available, the internal anatomy of this species appears to be normal. In one specimen the wrinkled foot was extended, showing two small pointed toes. The lateral antennae protrude high up above the middle on each side. (ref. ID; 3218)
Measurements
Length of lorica 285; width 224 µm. (ref. ID; 3218)
Lorica barrel-shaped, swollen at its posterior third, prolonged posteriorly in two stout and parallel lateral spines, their length is usually more than 1/2 the length of the body without spines. Greatest width/length of the body (without spines) ratio=1. Anterior dorsal margin with six well developed spines, medians longest and bent outwards, laterals slightly divergent. Anterior ventral margin undulate, somewhat elevated toward the center, with a median sinus. The ventro-posterior portion of the lorica forms a typical tubular sheath surrounding the foot opening. Lorica markedly stippled or pustulate. B. quadridentatus is a very common, widely cosmopolitan, highly variable species, having an extensive Synonymy. In Wiszniewski's (1954) catalogue about 80 Synonyms -including varieties-, that correspond to the literature published up to 1939, are listed. In further works several varieties or forms are also considered, but due to the existence of many intermediate forms, these so-called varieties are not sharply separable each from the other. (ref. ID; 775)
Six occipital spines of which the medians are longer and curved outwards. Lorica broader than long. Two posterior spines. Lorica stippled. (ref. ID; 1929)
Morphological variation: The specimens obtained during Nov. and Dec. resembled the typical forms having posterior spines. Some of them were found with rudimentary or no posterior spines belonged to var. entzi. During Feb. the length of the posterior spines increased slightly and the brevispinus condition was evident. Towards end of March and again in August-September months the melhini variety appeared in large numbers and other varieties were totally absent. In the melhini variety the posterior spines are longer and divergent; the occipital median spines are also longer than the typical. However, some forms appeared with posterior spines curved and bowed inwards. (ref. ID; 1939)
When viewed from the dorsal side the outline of the animal is trapezoidal, its greatest width being in the lumbar region. It has four occipital spines, the two medians being curved outwards, and having the appearance of antlers; the two outer spines are straight and slightly shorter than the central pair. Between the outer spines on each side a small saw tooth can be seen, and on the corresponding anterior ventral edge are two similar teeth. The posterior spines are long and sharp, and when viewed from the dorsal side make an angle of approximately 30 degrees, with a median line passing lengthwise through the body. Two short recurved spines protect the foot opening. The foot, which is often longer than the animal, is wrinkled, and has the usual two toes. (ref. ID; 2276)
A variable species. Anterior and posterior spines were well developed in all specimens examined. The lorica seemed to be longer than is usually described. Some specimens were heavily stippled while some were only lightly stippled. The foot sheath is well developed in some specimens projecting as blunt spines bounding the foot opening and is always asymmetric. (ref. ID; 2715)
Lorica firm, compressed dorso-ventrally, dorsal anterior margin with six outwardly curved spines, medians longest an laterals longer than intermediates. Foot opening bounded by two blunt asymmetric spines. (ref. ID; 2867)
This is the nominate form of B. quadridentatus having well developed anterior and posterior spines. Antero-median spines are larger than antero-lateral spines. Length of postero-lateral spines increases with the increase in the size of lorica. The variations in different forms of B. quadridentatus are due to initial appearance and subsequent development and elongation of postero-lateral and postero-median spines. The variations are also in the antero-median spines, whose length increase gradually from form I-V. With the increase in the width of lorica, the relative length of lorica decrease. Morphometric data of different morphological forms are given in tables 1 and 2. Following are the prominent morphometric changes in lorica and various spines in various forms of B. quadridentatus;
(i) Total length of lorica increases from forms I-V (i.e., 0.20-0.34 mm).
(ii) Width of lorica also increases gradually from 0.18-0.20 mm from forms I-V.
(iii) Length of antero-lateral and antero-median spines increases gradually and reaches its maximum in form V.
(iv) The retro between length of antero-median spines and postero-lateral spines decreases from forms II-V.
(v) The length of antero-median spine/length of lorica increases from 0.18 mm in form I to 0.31 mm in form V. (ref. ID; 2868)
Occipital margin with six spines. Medians longest, curved outward; laterals longer than intermediates. Mental margin elevated, wavy, with a median notch flanked on either side by a small tooth-like papilla. Lorica usually terminating posteriorly in two lateral spine, very variable in length on different individuals. Ventro-posterior portion of the lorica prolonged into a tubular sheath around the base of the foot. The sheath standing out at nearly right angles to the ventral plate. Foot sheath often asymmetric, particularly on forms having long postero-lateral spines, the right side having the longer cuticular process. (ref. ID; 3180)
Measurements
Total length 176-190; greatest width 104-112; anterior lateral spines 22-24; anterior intermediate spines 14-16; anterior median spines 28-33; posterior lateral spines 47-62 µm. Very small individuals; Total length 130; greatest width 90; posterior lateral spines 31 µm. (ref. ID; 775)
Specimens varied in body length from 150-270 µm. (ref. ID; 2317)
Maximum total length 210 µm. A large variety sizes was found, and also all stages of cyclomorphic variation. (ref. ID; 2385)
Total length 250; maximum width 140; occipital spines 16-10-40; posterior spines 96 µm. (ref. ID; 2704)
Total length 240; width 135; anterior lateral spines 21; anterior intermediate spines 9; anterior median spines 63; posterior spine 66 µm. (ref. ID; 2715)
Total length 340; length of lorica 160; maximum width 200; length of antero-lateral spine 25; length of antero-median spine 70; length of antero-intermediate spine 10; length of posterior spine 90 µm. (ref. ID; 2867)
Lorica 175x180; length of median occipital spines 28; length of lateral occipital spines 22; length of posterior spines 22 µm. (ref. ID; 3275)
Lorica widening toward its posterior part, corners with short, broad-based, rounded spines. The ventro-posterior portion of the lorica narrows abruptly and terminates in a long foot sheath, posteriorly placed, forming a pointed median projection. Anterior dorsal margin with short, broad-based spines. Lorica smooth. (ref. ID; 775)
Measurements
Total length 176; greatest width 155; anterior lateral spines 11; anterior intermediate spines 9; anterior median spines 17 µm. (ref. ID; 775)
Total length 160-164; width at the basis occipital lateral spines 94-100; widest part 139-140; anterior median sinus 22-28 wide, 25-34 deep; anterior lateral spines 14-18; pectoral median sinus 15 wide, 5 µm deep. (ref. ID; 3083)
Posterior lateral spines short, 1/3 to 1/8 the length of the body without spines. Anterior median spines divergent at tips but not markedly bent outwards as in the typical form. Lorica smooth. (ref. ID; 775)
This is characterised by the presence of postero-lateral spines of moderate length on both sides, as well as postero-median spines. Lorica is wider. (ref. ID; 2868)
Lorica firm, divided into a dorsal and a ventral plate, dorso-ventrally flattened. Occipital margin with six spines, the middle pair longest, curving outward; lateral longer than intermediates. Lorica terminates posteriorly in two lateral spines, usually short in this sub-species. Freshwater species, but encountered in estuaries. (ref. ID; 4594)
Total length 160-300; width at the basis occipital lateral spines 86-108; widest part 118-166; anterior median sinus 18-50 wide, 20-60 deep; anterior lateral spines 11-13; caudal projection or protuberance 20-118 µm. (ref. ID; 3083)
Brachionus quadridentatus f. cluniorbicularis (Skorikov, 1884) (ref. ID; 2812) or 1894 (ref. ID; 2868) reported year? (ref. ID; 2619), var. cluniorbicularis Skorikov, 1894 (ref. ID; 775, 1345, 3114) Skorikow (ref. ID; 2890), var. cluniobicornis (Skorikov, 1894) (ref. ID; 1347)
Synonym
Brachionus bakeri var. inermis Daday, 1908 (ref. ID; 1345)
Descriptions
Lorica pear-shaped, rounded posteriorly, without posterior spines, its greatest width is about 3/4 of the length from the anterior end. [Greatest width]/[Total length] ratio 0.88-1.08. [Width at the tips of the anterior lateral spines]/[Greatest width] ratio 0.55-0.57. Anterior spines short, medians only a little longer than laterals. Lorica smooth or with a pattern of cuticular lines. (ref. ID; 775)
There are 6 occipital spines of which median spines are longer and curved a little outwardly. Lorica is broader than long. This form is characterised by the absence of postero-lateral spines and rounded posterior corners. (ref. ID; 2868)
Measurements
Total length 180-238; greatest width 162-225; width at the tips of the anterior lateral spines 94-124; anterior lateral spines 13-18; anterior intermediate spines 8-14; anterior median spines 16-21; subitaneous egg 114x71; male 85 µm. (ref. ID; 775)
In 1894, Barrois & Daday published the results of a scientific expedition to the Near East, simultaneously in Hungarian and in French. In French version, one of the species novae is descried under the name of Brachionus melhemi. It was dedicated to the Drogman Melhem Ouardy of Beyrouth. In following years, this taxon was shown to be a form of B. quadridentatus, this its correct name ought to be B. q. f. melhemi. Owing to a transcription error, it has been called B. q. f. melheni (var. melheni) on several occasions, e.g. Harring 1913. Collin et al (1912) call it B. bakeri var. melheni. Ahlstrom (1940) reports melheni for the Hungarian, melhemi for the French text. Wiszniewski (1954) cites B. melheni Barrois & Daday, but reports B. melhemi minor Barrois & Daday. He is the first author to use a trinominal nomenclature. Voigt (1957), Bartos (1959) and Rudescu (1960) all speak of 'var. melheni'. Kutikova (1970) and Koste (1978) again use a trinominal nomenclature, suggesting Brachionus quadridentatus melhini to be a valid subspecies. Koste calls it characteristic for the tropical and subtropical water. A trinominal nomenclature has also been used by De Ridder (1983) in erroneous orthography melhini. In De Ridder (1984) the trinomial denomination was again used as B. quadridentatus melheni. But during recent investigations on plankton from Senegal, De Ridder found many transitional forms between B. q. quadridentatus and B. q. melhemi, and thus He reduced the latter to a 'forma' of B. quadridentatus. The correct name of this taxon is therefore B. quadridentatus f. melhemi. (ref. ID; 1839)
Descriptions
Posterior spines always divergent, representing more than 1/3 of the length of the body without spines. Lorica barrel-shaped, sometimes very broad, [greatest width]/length of the body (without spines) ratio may be >1. The lorica is usually asymmetrically swollen at its left side. Lorica smooth or slightly stippled. (ref. ID; 775)
A typical warm stenotherm species. (ref. ID; 1847)
In this form due to the increase in the width of lorica the ratio between its length and width becomes less. Only right postero-lateral spine of moderate length is developed. (ref. ID; 2868)
Brachionus quadridentatus f. rhenanus (Lauterborn, 1893) (ref. ID; 775, 2868), var. rhenanus (Lauterborn, 1893) (ref. ID; 1345, 1347, 3114, 3688)
Lorica barrel-shaped, its greatest width is about 2/3 of the length from the anterior end. Greatest width/total length ratio varies from 0.73 in young individuals to 1.0 in specimens having a rather inflated lorica. Posterior corners of the lorica almost rectangular. Posterior lateral spines very short or obliterate, representing less than 1/8 of the body length. Anterior spines usually shorter than in the typical form. (ref. ID; 775)
In this form the lateral and median occipital spines are almost equal in length. Intermediate spines are short. Two pairs of posterior spines are present. Postero-lateral spines are in the form of small body buds only. The postero-median spines are thus longer than the postero-lateral spines. (ref. ID; 2868)
Brachionus rotundiformis differs from the other two sibling species in four ways. First, the antero-dorsal spine pattern. Three pairs of antero-dorsal triangular spines, all sharply pointed; the median spine shorter than the others. Second, lorica semicircular shaped and dorsal-ventrally compressed; lateral antenna dorsally and slightly posteriorly located. Third, the body size is smaller than B. ibericus n. sp. and B. plicatilis. Fouth, shape and surface topography of resting eggs. Resting egg is kidney shaped, with a fairly rough surface, abundant pores irregularly distributed on the entire egg surface. Surface topography and egg shape differ from these described by Munuswamy et al. [(Munuswamy et al. 1996); see their Figures 5 and 6] for B. rotundiformis. (ref. ID; 6876)
Descriptions
Parthenogenetic female: Lorica soft, almost circular in profile and dorso-ventrally compressed. Dorsal and ventral plates fused laterally and posteriorly. Lorica surface smooth. Anterior dorsal margin with three pairs of spines, all triangular and sharply pointed flanking a U-shaped sinus. Median spines the shortest, having a characteristic acuminate shape. Anterior ventral margins with two pairs of lobules flanking a slender sinus; inner lobes roughly quadrangular shaped, and external ones slightly rounded; the latter followed by a sraight margin that reaches the lateral margins of the lorica. Lateral antenna located on the dorsal lorica, at about the posterior third. Foot aperture sub-terminal, on the ventral plate. (ref. ID; 6876)
Trophi: General morphology similar to that of B. ibericus n. sp. Fulcrum short. Rami roughly rectangular tetrahedron shaped; anterior processi soft and lamellate. Unci with four teeth-like structures proximally. Subuncus brush-like. Manubria flattened plate-like sructures, highly twisted and bent distally; three proximal cavities opened. (ref. ID; 6876)
Resting egg: Attached to the posterior part of the lorica when carried. Resting egg kidney shaped. Operculum with a fine scar-like structure, located at one end of the egg. Surface fairly rough with abundant pores irregularly distributed on the whole egg surface. (ref. ID; 6876)
Comments
As previously explained, from a re-examination of the available published names for the B. plicatilis morphospecies, Segers (Segers 1995) established that the correct name for the so-called S-type was B. rotundiformis Tschugunoff, originally described from the Caspian Sea (Tschugunoff 1921). Although this reassignment was an important step, we now know that this morphospecies [sensu (Segers 1995)] is not a single biological species, but is a complex of several cryptic taxa, each probably having a more restricted geographical distribution than the whole complex. It is worth pointing out that more than two cryptic species (i.e. B. ibericus and B. rotundiformis) have probably been included in B. rotundiformis sensu Segers. This would explain disagreements in morphological descriptions available in the literature [see for instance Sudzuki 1987; Munuswamy et al. 1996), and descriptions in this paper]. Besides these, no type material is available for comparison, and the probability of find the same animal species described by Tschungunoff (Tschugunoff 1921) is low because several species belonging to this species complex might coexist in the type locality. Consequently, we decided to re-describe this taxon from our Spanish material. This would allow further comparative works. Our clones correspond well to the original description by Tschugunoff (Tschugunoff 1921). (ref. ID; 6876)
Distribution and ecology
Brachionus rotundiformis Tschugunoff has been found inhabiting several ponds in two brackish marshes in the Eastern coast of Spain, [see the so-called 'cluster 0' in (Ortells et al. 2000)], that include three ponds in the Cabanes-Torreblanca Marsh [Poza Sur, Poza Norte and Canal Central, see (Gomez, et al. 1995)], and single pond in El Hondo de Elche National Park (Charca Norte). (ref. ID; 6876)
Designation of neotype
Since no original type material of B. rotundiformis is avaiable, and for the same reasons stressed above for the B. plicatilis Muller redescription, neotype material has been deposited and described from our Spanish strains. Deposit of reference material in public collections would allow further comparative research (morphology or genetics) that should clarify the actual status of this taxon. (ref. ID; 6876)
Material examined
Neotype: A parthenogenetic female, from a clonal population (strain SS2) maintained in the rotifer culture collection at the ICBIBE-UV, originally founded from a single amictic female collected in Cabanes-Torreblanca Marsh, September 17, 1993 (Gomez et al. 1995). Fixed (95%) and preserved (70%, with some drops of glycerine) with ethanol, vial deposited in the NHM (London, UK); catalogue number: NHM-2000.3111. (ref. ID; 6876)
Further material examined: Many more specimens, amictic and mictic females, and males obtained from the experimental and stock cultures belonging to strains SS2 (collection data as the neotype) and SHON (collected August 26, 1998). Thirty parthenogenetic females belonging to the SS2 strain from Cabanes-Torreblanca Marsh, and 30 parthenogenetic females of the SHON strain, from El Hondo de Elche National Park (Charca Norte). Specimens fixed and preseved as the neotype. Vials deposited in the NHM; catalogue numbers: NHM-2000.3112-3141 and NHM-2000.3142-3171. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain SS2) preserved with 70% ethanol into a vial, both deposited in the ANS (Philadelphia, USA); catalogue numbers: ANSP RO-1045 and RO-1048. One parthenogenetic female on a permanent glycerine glass slide sealed with Permount mounting medium, and 30 females (strain SS2) preserved with 70% ethanol into a vial, both deposited in the NMNH (Washington, USA); catalogue numbers: USNM189276-189277. Six trophi as SEM preparations, deposited in the ICBIBE-UV. Both of the clones are currently maintained in the rotifer culture collection at the ICBIBE-UV. (ref. ID; 6876)
Measurements
(Range and, in parenthesis, mean+/-SE; in µm) of adult (48+/-3 hr) animals culture at 23 degrees C, 12 g l-1 salinity: Female lorica length, 131.0-165.5(148.5+/-2.5); width 106.0-128.5(120.0+/-2.5); head aperture, 62.0-79.0(71.0+/-2.5); depth of dorsal sinus, 14-26(22+/-1); length of dorsal anterior spine 2 (median), 11-20(15+/-1); length of dorsal-anterior spine 3 (outer), 15-22(20+/-1). Trophi length, 25.0-28.4(26.6+/-0.7); fulcrum length, 7.1-8.6(7.8+/-0.4); manubrium length, 25.6-29.2(27.1+/-0.5); rami width, 23.3-26.5(24.4+/-0.8); uncus length, 113.2-113.8; width 13.3-16.6(15.1+/-0.4). Resting egg length, (113.5+/-0.5); width 74.0-75.9(75.0+/-1.0). Male length, 89.0-111.0(98.0+/-2.5); width, 49.0-59.5(55.0+/-2.5). (ref. ID; 6876)
Lorica oval, [Greatest width]/[Total length] ratio 0.74-0.78, the greatest width is a little below the middle of the lorica. Anterior dorsal margin with six saw-tooth spines, medians longest. Anterior ventral margin markedly elevated toward the center, notched medially. Posterior spines absent. Foot opening with a rectangular aperture dorsally and a larger rather oval aperture ventrally. Lorica smooth. (ref. ID; 775)
Occipital margin with six spines; each median and inter-mediate spine with a narrow anterior part, then rounded outwards and forming a broad base; four inner spines with short strengthening ridges. (ref. ID; 2704)
Lorica sturdy with six anterior spines of which the median spines are the longest. There is 'V' shaped median sinus. Intermediate and lateral spines are short and pointed. All the anterior spines have a strengthening rib. Lorica not ornamented. (ref. ID; 2715)
Lorica flexible, more or less oval, greater width, about 2/3 of the total length of lorica. Anterior dorsal margin with six spines, each median and intermediate spine with a narrow anterior part, then rounded outwards and forming a broad base, four inner spines with short strengthening ridges. (ref. ID; 2867)
Usually associated with Daphnia pulex (De Geer) or D. obtusa Kurz., on which it is epizoic or commensal but not parasitic in the true sense. (ref. ID; 3208)
Comments
Varga has published on the basis of several specimens originating in different localities in Hungary, a specified comparative description of its forms. The lorica is firm, flattened. The anterior spines diverge one from the other. The median spines are separated from each other by a deep indentation broadening towards the tip of the spines. The two outermost spines are weakly developed, in some cases they protrude hardly visibly. The anterior edge of the ventral plate is markedly divided, undulating, it practically follows the line of the spines of the dorsal plate. The posterior extensions of the lorica are distinct with a deeply widening foot aperture. The most striking difference is to be seen in the dimensions. As a against the dimensions of 180-240 um total length and 140-160 µm width published by Varga, the total length of the lorica is 262 µm and greatest width 203.5 µm. (ref. ID; 1489)
Measurements
Total length 190; greatest width 144; anterior lateral spines 13; anterior intermediate spines 11; anterior median spines 18 µm. (ref. ID; 775)
Length 220; max. width 180; anterior median spines 25; intermediate spines 12; lateral spines 20 µm. (ref. ID; 2277)
Body length over spines 170 µm. Small specimens having total length over spines of 100-120 µm. (ref. ID; 2385)
Total length 180; maximum width 130; anterior width 92; occipital spines 14-12-20 µm. (ref. ID; 2704)
Total length 144; width 102; anterior lateral spines 6; anterior intermediate spines 6; anterior median spines 12 µm. (ref. ID; 2715)
Total length 190; length of lorica 150; maximum width 140; length of antero-lateral spine 15; length of antero-median spine 20; length of antero-intermediate spine 10 µm. (ref. ID; 2867)
This species is well characterized in having 1) oval lorica, 2) a pair of triangular projection markedly elevated on pectoral margin and 3) unsymmetrical shape of median and intermediate spines of occipital margin. (ref. ID; 3083)
Measurements
Total length 178-186; width at the basis occipital lateral spines 108; widest part 130-138; anterior median sinus 15 wide, 28-29 deep; anterior lateral spines 25-28; pectoral median sinus 25-27 wide, 12-13 µm deep. (ref. ID; 3083)
Rousselet (1911) had specimens only which had been obtained in a plankton collection made in Devils Lake in the month of July, 1910, with two long, curved and widely separated posterior spines. The specimens from Prof. Young (a collection made in the month of May 1912, much earlier in the season, when the weather in North Dakota is still cold and the water chilly) was much smaller form, with short posterior spines, curved inwards and other unusual features. The six frontal spines and the mental edge are identical with those of the larger specimens, but the shape of the body and the form and size of the posterior spines are very different, and strangest of all, the foot-opening is situated on the postero-dorsal side of the lorica, a quite unheard of position in this genus. Rousselet first impression was that these were young animals just hatched from eggs, but this is evidently not so, for some specimens were seen carrying their eggs at the base of the foot on the dorsal side, and they were therefore adults reproducing freely. Rousselet can only concluded that this represents a case of dimorphism, possibly a winter form which gradually, in successive generations, transforms itself into the larger form with extended and expanded posterior spines. (ref. ID; 3218)
Measurements
The large form 408 and the small form 250 µm, in both case including the posterior spines. (ref. ID; 3218)
Regarded by Ahlstrom (1941) as a variety of B. urceolaris (Muller), but in the writer's experience B. sericus is found only in acid waters, whereas the type form of B. urceolaris appears to be confined to alkaline eutrophic waters. (ref. ID; 3208)
The anterior end of the lorica has four clear small spine-like projections with a fairly deep sinus between the median spines. Foot opening ventral, large and more or less round. Eggs were attached to the posterior end of some specimens. (ref. ID; 2715)
The body is stumpy, spherical; the lorica thin and flexible, without sculpture. On the frontal part of the dorsal half of the lorica are 2 central spines with wide bases, descending in waves on the exterior sides. A wide shallow bay separates the 2 spherical terminal spines. These are 2 other low, obtuse spines on the frontal borders. The frontal part of the ventral lorica descends in waves, with 2 small round elevations in the middle and a slight depression between them. The foot aperture is square, beside it the lorica has no sort of bulge or elevation. The foot is vigorous, 3-segmented, with 2 stubby toes. With these and the end of the foot it sticks to the body of the host, on the surface of which it deposes circular granulated patches of glandular secretion. Its corona and jaws resemble those of the other Brachionus species. Its dark-red single eye-spot is always clearly apparent. Only a few specimens adhere to one host. When gathering its food it bends down, with the ventral side attached to the surface of the host. It is only to be found in summer, hence it is a true warm stenothermous form. (ref. ID; 5026)
Comments
This species was first described by Varga (1951) from Lake Balaton, epizoic on Diphanosoma bachyurum (Lieven) and has not been reported since. In Sri Lanka B. sessilis was found from only one lake (Pavatkulam) and was living epizootically on Diaphanosoma excisum (Sars). (ref. ID; 2715)
This animal resembles B. rubens in many respects except its considerably smaller size. (ref. ID; 3387)
In order to establish its systematic place and relationships it was compared with Brachionus rubens Ehrbg. (= Br. urceus var. rubens auct.), Br. plicatilis Muller (and its varieties), Br. orientalis Rod. and Br. quadridentatus Kertesz. The nearest resemblance was to Br. plicatilis var. rotundiformis Tschugunov. There are, however, very great morphological and ecological differences. It is nonetheless possible that it has evolved from this variety, considered by Rodewald to be a different species. (ref. ID; 5026)
Type locality
The new species may have reached the Lake Balaton from the East by way of the Danube. (ref. ID; 5026)
Measurements
Length 94 µm, breadth 80 µm. (ref. ID; 3387)
Body dimensions: Length of lorica 95-115; width 90-98; thickness 70-80; width of foot aperture 17-20 µm. (ref. ID; 5026)
The lorica is very wide posteriorly, twice to nearly three times as broad as the anterior region, giving the animal a peculiar and characteristic triangular form. Young animals are not quite so broad in proportion. The six occipital spines are of the peculiar saw-tooth pattern as met with in B. mulleri, but considerably large in size. The scalloped pectoral edge has four rounded, slightly irregular projection. The posterior corners of the lorica are rounded off, and the foot-opening has thickened edges, is square dorsally and pointed and V-shaped ventrally. As a while the lorica is roomy, high and rounded dorsally and nearly flat ventrally, similar in these respects to that of B. mulleri. Like the latter, B. spatiosus is a brackish water form, for the water of Devil's Lake is distinctly brackish, which no doubt also accounts for the fact that it contains but few species of Rotifers, and no distinctly fresh-water forms, at least as far as the investigation of its fauna has extended. The lorica is thin, transparent had free from stipples and posterior spines. The internal organs are quite normal; the foot is fairly long and wrinkled, with the usual two toes. (ref. ID; 3216)
Male: Male were not found in the gathering. (ref. ID; 3216)
Egg: Summer eggs were carried posteriorly in the usual way, but no resting egg was observed. (ref. ID; 3216)
Comments
In shape and appearance the nearest forms are probably B. latissimus and B. longipes, of Schmarda. The former is considerably broader than long, and coarsely stippled on dorsal surface; the second is trapezoidal in shape, the mental edge slightly curved, with small notch in the middle, and the foot opening semicircular; in all these characters they differ from B. spatiosus. I was in doubt at first whether this form should not be called a variety of B. mulleri, with which structurally it is undoubtedly more nearly allied than with any other species; but after comparing it with the mounted specimens in my collection from various localities, I have decided to give it specific rank on account of its striking shape. (ref. ID; 3216)
Type locality
Devil's Lake, North Dakota, U.S. America. (ref. ID; 3216)
Measurements
Size of lorica of largest specimens: length 1/78 in. (326 µm); greatest width posteriorly 1/79 in. (320 µm); width anteriorly 1/220 in. (115 µm). (ref. ID; 3216)
Lorica oval, rounded posteriorly, [Greatest width]/[Total length] ratio 0.80-0.82, the greatest width is a little below the middle of the lorica. Anterior dorsal margin with six pointed spines, medians longer than laterals, laterals longer than intermediates. Anterior ventral margin undulate, with a shallow central sinus flanked on either side by a pointed protuberance. Foot opening with a rectangular aperture dorsally and a larger oval aperture in the ventral plate. Lorica smooth. (ref. ID; 775)
Lorica sturdy with longitudinal lines. The anterior spines have strengthening ribs. Lorica is lightly stipples especially at the edges. (ref. ID; 2715)
Lorica firm, oval, divided into a dorsal and a ventral plate. Anterior dorsal margin with 6 spines: median longest, laterals and intermediates about equal in length. Mental margin, rigid, undulate, somewhat elevated toward the center, with a central sinus. Posterior spines absent. Foot opening with a subsquare to rectangular aperture in the dorsal (basal) plate. (ref. ID; 3180)
Lorica firm, divided into a dorsal and ventral plate. Anterior dorsal margin with six sharp pointed spines; medians longest, laterals and intermediates about equal in length. Ventral margin undulate. Posterior spines absent. Lorica with a pattern of wavy lines; pointed posteriorly in lateral view. Freshwater species, and also littoral near estuaries. (ref. ID; 4594)
Measurements
Total length 192; greatest width 157; anterior lateral spines 10; anterior intermediate spines 6; anterior median spines 17; length of dorsal foot aperture 16; length of ventral foot aperture 35; length of sinus between anterior dorsal median spines 22 µm. (ref. ID; 775)
Length 260; max. width 210; anterior median spines 30 µm. (ref. ID; 2277)
Total length of lorica 245 µm. (ref. ID; 2715)
Length of ventral lorica 200 µm. (ref. ID; 2891)
Total length 210-280; widest part 176-180; middle part 116-120 high; occipital sinus 14-32 long, 16-18 wide, 30-36 deep; anterior intermediate spines 10-20; anterior lateral spines 18-20; fertilized dormant egg 140x92; thelytokous egg 88x66-68 µm. (ref. ID; 3083)
Total length 190-270; width 140-210 µm. (ref. ID; 4594)
In lateral view, the specimens resembles B. urceolaris. (ref. ID; 1837)
Brachionus urceolaris amazonica is characterized by the previously unknown structures on the dorsal lorica which can be pronuncedly different within the same population. The ornamental granulation on the dorsal lorica, characteristic of B. bennini, is lacking. (Compare with De Beauchamp 1939: 9, Fig.2 or with Koste 1978, T.9, Fig.8). Also, the number and arrangement of the anterior spines and the shape of the foot agree better with the morphological and taxonomical characteristics of B. urceolaris. A "dwarfing form" mentioned by Green (1971) was not evident. (ref. ID; 2808)
Comments
This Brachionus was first encountered by the senior author in a sample from Igarape Curui, a tributary of the Rio Solimoes, and erroneously identified as B. bennini. (ref. ID; 2808)
Lorica oval, [Greatest width]/[Total length] ratio 0.71-0.89, the greatest width is about 2/3 of the distance from the anterior end. Anterior dorsal margin with six bluntly rounded, greatly reduced spines, showing a lobated sinus. Anterior ventral margin undulate, somewhat elevated toward the center, with two median papilla-like protuberances, without central sinus. Foot opening with a rather variable U-shaped aperture in the dorsal plate and a larger oval aperture ventrally. Lorica smooth or with a pattern of cuticular longitudinal lines, sometimes with a strengthening transverse groove in the posterior third and two short ridges starting near the anterior border. This species is readily distinguishable from other Brachionus-forms belonging to the urceolaris-group through the greatly reduced, rounded anterior spines. The outline of the body shows comparative similarity to B. sericus Rousselet, 1907, the latter however has a strongly ornamented lorica, with a pattern of distinct stripes, and the anterior spines of different shape. (ref. ID; 775)
Measurements
Total length 174-195; greatest width 130-173; width at the tips of the anterior lateral spines 90-110; anterior lateral spines 2-3; anterior intermediate spines 3-4; anterior median spines 4-11; length of dorsal foot aperture 22-32; length of ventral foot aperture 37-51; length of sinus between anterior dorsal median spines 13-16; subitaneous egg 100x80 µm. (ref. ID; 775)
This species is separable from urceolaris O.F. Muller in having 1) a semicircular lorica suddenly swollen at the posterior half, 2) smaller size, 3) posterior extremity in lateral view not so sharply pointed at in u. urceolaris, 4) asymmetrical caudal protuberances like angularis or reduced groups of forficula and 5) no constriction at the base of anterior lateral spine (cf. specimens by Weber 1898 & Beauchamp 1939). In this connection, it is worth mentioning that this kind of swollen lorica has, in general, been found in mixohaline Brachionus such as baylyi, pterodinoides, spatiosus, etc. Nevertheless, no intermediate forms have been recognized between urceolaris and semicircularis. (ref. ID; 3083)
Etymology
The name "semicircularis" is derived from the Latin "circus" for circle, and "semi" for half, alluding to the form of the lorica. (ref. ID; 3083)
Type locality
Mangrove marsh, Loyang. (ref. ID; 3083)
Measurements
Total length (TL) 136-170; width at the basis occipital lateral spines 98; widest part (WP) 96-136; WP/TL 0.7-0.8; anterior extremity 78 high; highest part 101 (swollen part); caudal extremity 54 high; anterior median sinus 28-32 deep; anterior lateral spines 18-20; distance between caudal protuberances at the base 12 µm. (ref. ID; 3083)
Lorica of heraldic outline without lateral posterior spines and with short anterior spines, median of which is a little longer. Dorsal lorica short, ventral lorica caudally tapering. Foot opening without protruding tube, ventral arch egg shaped, caudal trapezoid. Ventral anterior lorica margin plain, upper dorsal lorica with two stout ribs beginning between median and submedian spines and running in direction of periphery. Submedian spines reinforced with short cuticular outer borders. Lorica surface and foot opening reinforced dorsally, weaker ventrally and covered with granular structures. In lateral view, caudal lorica margin occasionally appears two-stage, elevated by sharp edge from narrow platelike base of foot tube opening. In dorsal view, two convex lines appear over foot tube, define boundary beneath dorsal lorica. (ref. ID; 2759)
Comments
The lorica outline of the new B. urceolaris sericus form, with an elevated caudal section, resembles that of B. quadridentatus forms from the literature. In particular, B. quadridentatus var. ancylognathus (Schmarda, 1859) and B. quadridentatus var. cluniorbicularis Skorikow, 1884. The lorica surface of this distinctive polymorph, as in the quadridentatus species group, is granulated and dimpled, with tiny ridges present. Nevertheless, urceolaris and quadridentatus taxa are readily distinguished; the latter always has a projecting foot tube, whereas the former has only a flat foot opening incised at the end of the ventral plate. Therefore, this taxon from northern Australia is considered a Brachionus urceolaris form of the subspecies sericus after Hauer (1963) from B. urceolaris f. sericus (Rousselet, 1907). (ref. ID; 2759)
Measurements
Lorica length 120-220, lorica width 80-172; Foot opening ventral 52 high x 40 wide, dorsal 12 high x 15 µm wide. (ref. ID; 2759)
The lorica is distinctly rounded and without ornamentation. The anterolateral and anteromedian spines are longer than intermediate spines. All the spines have a broad base. No strengthening ribs for the spines were discernible in specimens from Sri Lanka. (ref. ID; 2715)
Comments
B. urceus is similar to B. urceolaris but differs from it in its smaller size and the shape of the anterior spines. (ref. ID; 2715)
As the name indicates, the species is quite variable in habitus. In particular, posterior spines may appear on the lorica and grow out to considerable length. A rather important specific character is the dorsal subquadrate plate projecting over the foot opening. In rare cases this may be more or less reduced, as stated by Beauchamp (1947) and Murray (1915) (?) (cited by Beauchamp 1947). These specimens were considered as intermediate between Brachionus variabilis and Brachionus novaezealandiae, a tropicopolitan species. Gillard (1948) thinks this is a sufficient ground for synonymising the two, but this point of view has not been widely followed in textbooks (Voigt 1957; Ruttner-Kolisko 1972). The species was originally described from Havana, Illinois (Hempel 1896). (ref. ID; 2912)
This species resembles, in general view, novae-zelandiae rather than variabilis. The new subspecies differs from both in 1) weakly elevated pectoral margin, 2) very short intermediate spines and 3) features of caudal region. (ref. ID; 2874)
Type Locality
Kohama Jima site 3. (ref. ID; 2874)
Measurements
Lorica length 100-140; widest part 70-100; width at the anterior extremities 70-88; elevation of pectoral margin 4-7; occipital median sinus 17-22 µm. (ref. ID; 2874)
The chief variation from the type is the longer intermediate spines, which are turned inwards at an angle of almost 90 degrees to laterals. (ref. ID; 2284)
Measurements
Total length 250; width 110; length of posterior spines 100; length of anterior spines-lateral 40; intermediate spines 20, median spines 45 µm. (ref. ID; 2284)
