The World of Protozoa, Rotifera, Nematoda and Oligochaeta
Filinia
Filinia Bory de St. Vincent, 1824 (ref. ID; 7815)
Class Rotatoria: Order Monimotrochida: Family Filiniidae (ref. ID; 7097)
Synonym Fadeewella Smirnow, 1928 (ref. ID; 1923), Pedetes Gosse, 1886 (ref. ID; 2978), Triarthra Ehrenberg, 1832 (ref. ID; 1345, 2978, 3514, 3688) or 1834 (ref. ID; 3050)
ref. ID; 680
The genus is illoricate and bears two lateral skipping bristles of variable length and a caudal bristle; the trophi are malleoramate. (ref. ID; 680)
ref. ID; 1027
Identification to species level within the genus Filinia has relied until now on relative measurements, in particular the relationship between the lengths of lateral and caudal setae (bristle), and the position of insertion of the caudal setae (bristle). Also, habitat information has been used to aid identification. Ruttner-Kolisko (1974) classified all known taxa belonging to the genus on the basis of their external morphology and ecology into the longiseta-terminalis, brachiata-cornuta, and opoliensis-minuta groups. Taxonomic confusion is greatest in the first of these groups which includes at least ten nominal species (Ruttner-Kolisko 1989). The two other groups seem to be less common in occurrence, and species within them are well characterized. Within the longiseta-terminalis group, F. terminalis differs from F. longiseta in having the rigid caudal seta inserted less than 15 µm from the posterior end of the body, and in most cases it is terminally located (Pejler 1957; Hutchinson 1964; Ruttner-Kolisko 1974). F. longiseta has a moveable caudal seta inserted ventrally rather than terminally, its maximum distance from the posterior end being 43 µm (Schaber & Schrimpf 1984). The caudal seta can be easily distinguished in the two species, even in preserved specimens. The ecology on these two species is also dissimilar. F. terminalis considered to be a cold-stenotherm that occurs at temperatures less than 15 degrees C, whereas F. longiseta is an epilimnetic thermophile, living at temperature from 15 degrees C to 28 degrees C (Ruttner-Kolisko 1980; Schaber & Schrimpf 1984). The lateral to caudal seta length ratio is often stated to be fairly constant in a particular species had asymmetrical unci teeth; the left uncus always containing fewer teeth than the right one. (ref. ID; 1027)
ref. ID; 3086
The insertion of the posterior seta is of taxonomic importance in identifying the species of Filinia (Pejler 1957; Hutchinson 1964). Hutchinson (1964) states that the insertion of the posterior seta of Filinia terminalis, if not terminal, is usually less than 10 µm from the posterior end of the body. Pejler (1957) observed some specimens in Sweden with the posterior seta inserted up to 28 µm in front of the posterior end. In a number of specimens examined by the authors, it was found that the insertion of the posterior seta was in the range of 5 to 32 µm from the posterior end. The shape of the body of Filinia longiseta and Filinia terminalis did not show any recognizable difference in the preserved state. (ref. ID; 3086)
ref. ID; 4596
Body sac-shaped, without lorica. With two lateral and one posterior spine. (ref. ID; 4596)
F. australiensis, F. grandis, F. hofmanni, F. longiseta limnetica, F. longiseta longiseta, F. novaezealandiae, F. passa, F. pejleri, F. salter, F. terminalis kergueleniensis, F. terminalis terminalis
This species has a large globular body with thick appendages. The caudal seta is moveable, and inserted 40-60 µm from the posterior end. The trophi are 39-44 µm long, and have 22-23/25-26 unci teeth. (ref. ID; 1027)
SEM micrograph illustrating trophi. (ref. ID; 6844)
The body was somewhat contracted, with a length of 88 µm. The posterior seta was inserted on the ventral side of the body and reached a length of 38 µm. The two anterior setae were 110 µm in length, which was probably about equal to the body length in life. (ref. ID; 2683)
The shape of the lorica is circular, truncate anteriorly. Lorica is firm. Two lateral spines have swollen bases. The terminal spines are straight and end in shape points. (ref. ID; 2715)
It seems that Filinia camasecla Myers has not been after the first discovery in Panama (Myers 1938). Probably the F. brachyata of Yamamoto from China (1944) can be this species, as the lateral spines are placed on the middle of the trunk. But the figure and text are too simple. It is impossible to make it clear. I found this species in the Mekong-system in the environment of Phnom-Penh. My animals differ from those from Panama with a distinctly narrowed lorica occipital in front of the lateral spines, which is situated on a solid fold. The posterior spine of my animals has a very distinctly developed joint, which is not seen on Myers's specimens. The animal have 2 eyes, I separate my organisms into a new subspecies Filinia campasecla cambodgensis n. subsp. The individuals from Canbodia is somewhat larger than those from Panama. (ref. ID; 3019)
Measurements
Length of the lorica 95-104; width of lorica 91-92; width of the body, occipitally 60-66; length of lateral spines 117-127; length of posterior spines 100-112 µm. (ref. ID; 3019)
Filinia pejleri var. grandis Koste, 1979 (ref. ID; 1027)
Descriptions
This species is known only from Australia, and therefore is considered to be an Australian endemic. The body is very narrow and spindle-shaped with asymmetrical lateral setae. It is the largest Filinia species known (body length to 325 µm long; Koste, 1979). The strong, broad base of the caudal seta is inserted terminally. (ref. ID; 1027)
Body narrow, elongate fusiform, tapering to caudal seta, often with a slight bulge at the body/seta injection; caudal seta inserted at level of anus, with average width at insertion of 40 µm, no rounding of the posterior; anterior setae asymmetrical, left longer than right; all setae finely spinulate; trophi to 32 µm long, with shortest uncus tooth 9.6 µm; 21/21 unci teeth figured in original description, however specimens with 17/19 and 19/20 teeth co-occurred in a sample. It was initially described by Koste (1979) as F. pejleri grandis, but it to be distinct species on the basis of trophi structure and ecological differences; setal length ratios and trophi features, and its distinct cold-stenothermal (<13 degrees C) habit is in marked contrast to F. pejleri, which appears to be a warm stenotherm or eurystenothermal. (ref. ID; 1706)
Measurements
Body length 211-292 µm; lateral setae 381-816 µm; caudal seta 605-714 µm; caudal seta thickened at base: yes; distance of insertion of caudal seta from end of body 0; ratio lateral seta: body length 1.8-2.9; ratio lateral setae: caudal seta <1; trophi length 24-32 µm; number of unci teeth 19-20; length of unci teeth; 10- µm. (ref. ID; 1706)
This species is a cold-stenotherm, which occurs in the hypolimnion of eutrophic and meromictic lakes (Hofmann 1982). The body resembles that of F. longiseta, but the trophi have fewer unci teeth. F. hofmanni has a tooth formula of 13-14/14-16 unci teeth. (ref. ID; 1027)
This species is a warm-stenotherm, found only in shallow, eutrophic lakes or ponds (ex. oxidation ponds), at temperatures between 18 degrees C and 23 degrees C. It has a moveable caudal seta. The distance from the posterior end to the point of insertion of the caudal seta is at least 40 µm. The trophi are 24-30 µm long, and have tooth formulae of 18-19/20-21 (left/right). (ref. ID; 1027)
Body thin, fairly long, cylindrical. With two long anterolateral setae and one posterior seta; posterior seta situated ventrally, away from the terminal point, its point of insertion variable. (ref. ID; 1804)
Body fairly long and cylindrical. Posterior seta inserted ventrally. (ref. ID; 2704)
Body fairly broad. The posterior seta is almost invariably ventrally situated. (ref. ID; 2715)
Body illoricate, more or less transparent. Two long antero-lateral setae below the head and one posterior seta. Posterior seta ventrally situated and away from the terminal point. (ref. ID; 2867)
There is a circumapical ring of cilia. There are two trochal discs which are not so well pronounced as in bdelloids. The trochal discs also bear cilia which are longer than those at the circumapical ring. Mastax is malleo-ramate. There is a well developed fulcrum, a pair of rami, a pair of manubria each divided into three parts. There are two unci which have numerous teeth. (ref. ID; 3050)
Vitellarium with 8 nuclei. Unci with ca. 26 teeth. (ref. ID; 3083)
If lateral spines are only 2-3 times as long as the body. It is forma typica, but if the spines are more than 4 times as long it is called longiseta limnetica (Zacharias). Freshwater species, also found in estuaries. (ref. ID; 4596)
Egg: (ref. ID; 3114)
Quote from ref. ID; 3114
Male: Male present. (ref. ID; 3067)
Quote from ref. ID; 3067
Measurements
Body length 145-208; anterior spines length 216-478; posterior spines length 216-270 µm. Ratio body length/anterior spine length at beginning of the season 1:1.5, at the end of the season almost 1:4. Smallest body size and longest spine in summer. (ref. ID; 1402)
Body length 175-200; lateral setae 300-330; posterior seta 190-240 µm. (ref. ID; 1804)
Body length 180-195 µm. (ref. ID; 2704)
Length of body 200 µm. (ref. ID; 2715)
Body length 130-250; length of caudal bristle 125-300; length of lateral bristle 320-590; trophi length 36-43 µm. (ref. ID; 2809)
Body length 120; anterior setae 320; posterior seta 190 µm. (ref. ID; 2860)
Total length 220; maximum width 100 µm. (ref. ID; 2867)
Maximum body length 117; maximum body breadth 55; length of each lateral spine 230; length of posterior spine 154 µm. (ref. ID; 3050)
Body length (BL) 98-105; body width (BW) 49-50; BW/BL 0.5; anterior extremity 36-39 high; highest part 45-50; caudal extremity 20 high; lateral spines (LS) 250-312; caudal spines (CS) 170-198; LS/BL 2.6-3.0; LS/CS 1.4-1.6; CS/BL 1.8-1.9; thelytokous 40 µm. (ref. ID; 3083)
Body length (contracted) 130; length of anterior appendages 250-290; length of posterior appendage 190 µm. (ref. ID; 3275)
Length of body 130-250; length of lateral spines 240-500; posterior spine 130-400 µm. (ref. ID; 4596)
The morphological features of this species resembles those of F. longiseta longiseta, except that the appendages are approximately four times longer than the body (Pontin 1978). Both F. longiseta limnetica and F. longiseta longiseta occur mainly in summer, but they differ ecologically. F. longiseta limnetica has been found in large lakes, whereas F. longiseta longiseta occurs in ponds or small, shallow lakes (Hutchinson 1967). F. longiseta limnetica has been recorded in temperate and some subtropical waters in Europe, Australia, and South America. (ref. ID; 1027)
Male: Male present. (ref. ID; 3067)
Filinia maior (Colditz) Carlin, 1943 (ref. ID; 1345, 3688); Triarthra longiseta terminalis Slonimski, 1926 (ref. ID; 3688); Triarthra maior Plate, 1886 (ref. ID; 3688); Triarthra terminalis var. maior Colditz, 1914 (ref. ID; 3521, 3688) or 1924 (ref. ID; 1345, 2284)
Descriptions
Pejler (1957) regards this species as a synonym of F. terminalis. (ref. ID; 1923, 2553 original description)
Measurements
Length of body 120-130; anterior appendages 300-320 and 350-380; posterior appendage 200-230 µm. (ref. ID; 2284)
Length of body 110; length of anterior setae 270 and 290; length of posterior seta 200 µm. (ref. ID; 3521)
F. novaezealandiae occurs perennially, with maximum densities in summer at >20 degrees C. The external morphology of F. novaezealandidae is similar to that of F. terminalis terminalis. The trophi are 19-25 µm long, with 18-19/19-20 (left/right) unci teeth. (ref. ID; 1027)
From formalin-preserved material in various stages of contraction: Small, cylindrical oviform body, posteriorly rounded, but may be fusiform in contracted individuals. Body length 1.8-2.1 times width; insertion of caudal seta to 10 µm form the posterior end of body; insertion of retractor muscles on body wall anterior to caudal seta; trophi structure: trophi length 22-24 µm; rami length 14-16 µm; fulcrum 4-6 µm; manubria length 12-14 µm; number of unci teeth 18/19-18/20; unci length 10-14 µm. (ref. ID; 1706)
S.E.M. photographs. (ref. ID; 7851)
Body long, cylindrical; with two long broad-based setae, posterior seta with an additional small seta (spine). (ref. ID; 1804)
With two long broad-based anterior setae; posterior seta with an additional small seta (= spine). (ref. ID; 2704)
Body cylindrical with two anterior spines which have broad bases. Anterior spines very long. Of the two posterior spines the longer one is as long as the anterior spines. The smaller spines in all specimens examined are very small measuring up to about one-sixth of the longer posterior spine. Because of their long spines they entangle each other and are often seen clumped together. (ref. ID; 2715)
Measurements
Body length 140-180; longer posterior seta 200-220; small posterior seta 36-50; anterior setae 240-280 µm. (ref. ID; 1804)
Body length 150-166 µm. (ref. ID; 2704)
Length of body 209; anterior spines 369 and 197; posterior spines 221 and 36 µm. (ref. ID; 2715)
Body length 169-204; right anterior bristle < /= 450; left anterior bristle 450-650; caudal bristle 400-600; caudal secondary bristle 0-143; subitaneous egg 90, 45; male egg 72, 36; trophi length < /= 36 µm. (ref. ID; 2891)
The external features of F. passa are similar to those of F. longiseta longiseta, but the former species has markedly shorter setae. It appears to have 15/15 (left/right) unci teeth (Koste 1980). It has been recorded in ponds and canals in England (Pontin 1978), and in billabongs of south-eastern Australia (Shiel & Koste 1983). (ref. ID; 1027)
F. pejleri appears to occur in oligotrophic, mesotrophic, and dystrophic lakes, with temperatures between 7.5 degrees C and 15.0 degrees C. This species has a spindle-shaped body. The base of the caudal seta is greatly enlarged, and resembles that of typical f. pejleri Hutchinson, 1964 and F. terminalis kergueleniensis Lair & Koste, 1984. Trophi are 23-31 µm long, with 16-17/17-19 unci teeth. (ref. ID; 1027)
Body fusiform, width about 1/3 or 1/4 of its length. Setae minutely spinulose. Posterior seta with a broad oblique base, inserted terminally at the posterior end of lorica. (ref. ID; 1804)
Body spindle shaped. Dorsal and ventral sides are rounded. F. pejleri is the smallest member of this genus. (ref. ID; 2715)
It is characterized by a caudal part which continually tapers to the insertion of the caudal bristle. (ref. ID; 2834)
Filinia pejleri pejleri Hutchinson is characterized by a spindle-shaped body, asymmetrical lateral bristles and the base of the rigid caudal bristle arising at the gradual tapering of the body. (ref. ID; 2891)
Measurements
Body length 124-200 µm; lateral setae 300-480 µm; caudal seta 242-456 µm; caudal seta thickened at base: yes; distance of insertion of caudal seta from end of body 0; ratio lateral seta:body length 2.4-3.7; ratio lateral setae: caudal seta 1.2-1.8; trophi length 29-31 µm; number of unci teeth 15/17, 16/17, 17/18; length of unci teeth; 15-17 µm (ref. ID; 1706)
Body length 138; maximum width 50; right anterior seta 340; left anterior seta 300; posterior seta 258 µm. (ref. ID; 1804)
Length of body 180 µm. (ref. ID; 2715)
Body length (contracted) 128; lateral bristles 300/320; caudal bristle 268 µm. (ref. ID; 2834)
Body length 138-200; right anterior bristle 308-456; left anterior bristle 300-480; caudal bristle 242-456 µm. (ref. ID; 2891)
Filinia pejleri grandis (Koste, 1979) (ref. ID; 680, 1834), var. grandis Koste, 1979 (ref. ID; 2891 original paper)
Synonym
Filinia pejleri var. grandis Koste, 1979 (ref. ID; 1834)
Descriptions
This species is distinguished from the F. pejleri through its exceptionally large body and bristle measurements. Filinia pejleri grandis has been sympatrically with an as yet undescribed variety of F. longiseta. The almost infinitely variable transition of the caudal bristle from the spindle shaped body, and the different lengths of the lateral bristles. (ref. ID; 1834)
In comparison with Filinia pejleri pejleri Hutchinson, 1964, the most conspicuous differences are in the characteristic body- and bristle-length measurements. The body has a narrow, spindle-shaped appearance. The caudal bristle is inserted at the height of the anus, with an average base width of 40 µm. With the exception of the lateral bristle, the new variety resembles F. opoleinsis (Zacharias, 1898). The new variety possesses asymmetrical lateral bristles which, like the caudal bristle, have fine secondary spinules. (ref. ID; 2891)
Filinia longiseta f. saltator (Gosse) after Pourriot, 1975 (ref. ID; 2809); Filinia longiseta var. caudata Hauer, 1953 (ref. ID; 2809); Filinia longiseta var. saltator (Gosse 1886) after Koste, 1980 (ref. ID; 2809); Pedetes saltator Gosse, 1886 (ref. ID; 2809)
Diagnosis
This species was described by Gosse (1886, in Koste 1978) under the species name F. saltator, thereafter considered as a form of F. longiseta (Hauer 1965 under the synonym acaudata, Pourriot 1975, Koste 1980) and, more recently, again as a distinct species (Koste et al. 1984). Koste et al. described some individuals can possess a very short caudal seta, shorter than the body length. (ref. ID; 1908)
F. saltator was present most of the time with the variety of forms. Different from F. longiseta, the caudal bristle of F. saltator, when present, is never longer than the body. The trophi has 21 teeth as in F. longiseta, but it is much smaller (28-30 µm long versus 36-40 µm long in F. longiseta). Unfortunately the description of Pedetes saltator by Gosse is dubious. According to Harring (1913: 48) Wesenberg-Lund pointed out that the taxon was probably a F. longiseta with the posterior spine broken off. Thus, while the type was found in England, the species was never again found in Europe. Hauer (1953), who first found F. saltator in the Neotropics (NE-Brazil), called it F. longiseta var. acaudata. (ref. ID; 2809)
Descriptions
The caudal seta was absent. (ref. ID; 1831, 1908)
Measurements
Trophi length 25; unci teeth (left/right) 15-16/15-16. (ref. ID; 1831)
Body length 100-135; length of caudal bristle 0-100; length of lateral bristle 240-320; trophi length 28-30 µm. (ref. ID; 2809)
The most significant characteristic used in identifying this taxon is the number of unci teeth. The trophi are 24-31 µm long, and the tooth formula is 14-15/16-17 (left/right). And, another prominent character is an immoveable caudal seta. To distinguish these feature, preserved specimens are preferable. The caudal seta always points posteriorly and is never upright as in F. longiseta longiseta. Setal lengths of individuals from different lakes can vary widely. These features appear to depend on water temperature; decreases in body size and setal length occurring with increasing temperature (Sanoamuang 1992). (ref. ID; 1027)
SEM micrograph illustrating trophi. (ref. ID; 6844)
Comments
I agree with Edmondson (1935) that F. terminalis (Plate) is not a synonym for F. longiseta Ehrenberg. Apart from the much greater size of F. terminalis it differs from F. longiseta in both the anterior and posterior details and shape of body. (ref. ID; 2280)
Unfortunately no illustration has been added by Plate (1886) to his description of Filinia terminalis. This omission has given rise to unnecessary speculations. Thus Edmondson and Hutchinson (1934) report from northern India a form which on account of its "small narrow spindleshaped body" "is a quite different organism to" a form with broader body discovered in Poland by Slonimski (1926). Edmondson and Hutchinson "believe" the Indian form to be "the true terminalis". This is explained by the fact that part of their material had been examined by D. Bryce who determined the form in question as F. terminalis. Plate's description contains, however, no suggestion that his form should be particularly narrow. It says on the contrary that the differences between F. terminalis and F. longiseta (Ehrenberg) "welche der neuen Species in allen andern Punkten nahe steht" are restricted to the point of insertion of the posterior process and to the thorns upon the appendages. All forms of Filinia with terminal posterior process which have been pictured have furthermore, as far as the present author has been able to find, a broad body, the form of Edmondson and Hutchinson being the only exception; among investigations on European material I refer in this context to Calman 1892 Pl.8:3; Colditz 1914 Fig.6; Carlin 1943 Fig.4b, and to the measurements given by Slonimski (1926). Thus everything points in the direction that these specimens of Filinia with broad body should be called F. terminalis. The author does not wish to exclude the possibility of Edmondson and Hutchinson's narrower form representing another species. The solution of this problem is no possible at the present moment, on account partly of the small material of Edmondson and Hutchinson's form, and partly of the relatively small morphological differences from the European specimens of F. terminalis, these differences being small with regard to the extensive intraspecific variation occurring among plaktonic Rotatoria, and not the least within the genus Filinia. Carlin (1943, p.36) has accepted the statements in Edmondson and Hutchinson, and has found himself compelled to erect a new species for his form from central Sweden, by reason of its broad body. He has called it F. maior after "Triarthra terminalis var. maior" established by Colditz. It appears, however, from the above that Carlin's specimens have to be named Filinia terminalis. (ref. ID; 2553)
Edmondson (1935) opinion: The original description of this species, unaccompanied by a figure, is highly unsatisfactory; however, Calman (1892) figures under that name an animal that is indubitably a terminalis as recently defined by Edmondson and Hutchinson (1934). For that reason, this name should be used despite the fact that there is nothing in the original description to differentiate terminal from forms of longiseta with a terminal spines. (ref. ID; 2760)
Measurements
Body length 100-200 µm; Length of lateral bristle 280-460 µm; Length of caudal bristle 160-370 µm; caudal bristle thickened at base: no; distance of insertion of caudal bristle from end of body 2-15 µm; ratio lateral bristles: body length 1.5-2.8; ratio lateral bristle: caudal bristle 1.25; number of nuclei in vitallarium 16-20; trophi length 28-32 µm; number of unci teeth 15/15, 15/16, 16/16; length of unci teeth; 10-13 µm. (ref. ID; 680)
Body length 400; appendages 500 and 480 µm. (ref. ID; 2280)
Length of body 200 µm. (ref. ID; 2715)
A typical specimen from Arizona are: length of body 200; dorso-ventral depth 60; length of right anterior seta 432; length of left anterior seta 480; length of posterior seta 360 µm. (ref. ID; 2760)
Length of body 101; width of body 50; length of anterior appendages 300; length of terminal appendage 200 µm. (ref. ID; 3127)
This species has a caudal bristle with a strongly thickened base. Its bristle are longer and always have spines. The main body is also longer, and the insertion of the caudal bristle is at the extreme end of the body; This end tapers to the caudal spine, like those Filinia pejleri and F. pejleri grandis. It differs from Filinia pejleri grandis by the presence of symmetrical lateral bristles and fewer teeth on the unci (Filinia pejleri has 21/21). (ref. ID; 680)
It is a cold-stenotherm, and is known only at temperatures between 0.1 degrees C and 8 degrees C. Filinia terminalis kergueleniensis has external features like those of F. pejleri, but its ecology in more like that of Filinia terminalis terminalis. It appears to have some number of unci teeth (16/16) (left/right) as Filinia terminalis terminalis. (ref. ID; 1027)
Measurements
Body length 130-310 µm; length of lateral bristle 410-700 µm; length of caudal bristle 300-560 µm; caudal bristle thickened at base: Yes; distance of insertion of caudal bristle from end of body 0 µm; ratio lateral bristles: body length 2.1-3.6; ratio lateral bristle: caudal bristle 1.1-1.4; number of nuclei in vitellarium 16-19; trophi length 32 µm; number of unci teeth 16/16; length of unci teeth; 10-16 µm (ref. ID; 680)
