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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Sinantherina

Sinantherina Bory de St. Vincent, 1826

Synonym Megalotrocha Bory de St. Vincent, 1826 (ref. ID; 1345, 1923, 2572, 3514, 3688); Voronkowia Fadeew, 1925 (ref. ID; 3688)

ref. ID; 1663

Adults in spherical, sessile colonies attached to aquatic plants. Colonies without tubes. Trunk usually with two to four opaque protuberances. Corona roughly kidney-shaped. (ref. ID; 1663)

ref. ID; 1923

Eggs are attached to specialized structure on foot (oviferon) found only in this genus. (ref. ID; 1923)

ref. ID; 2737

Colonial Floscularidae in which the corona is kidney-shaped and without lapettes and in which egg-carrier is present. Individuals are not embedded in a gelatinous matrix and are attached by their posterior ends to from a colony. (ref. ID; 2737)
  1. Sinantherina ariprepes Edmondson, 1939 (ref. ID; 1923, 2703, 2737, 2761 original paper, 3259, 3508)
  2. Sinantherina procera (Thorpe, 1893) (ref. ID; 1847, 1923, 2703) or 1758 (ref. ID; 2737)
  3. Sinantherina semibullata (Thorpe, 1889) (ref. ID; 1345, 1923, 2545, 2572, 2619, 2715, 2737, 2757, 3514) reported author and year? (ref. ID; 3292)
    Syn; Megalotrocha binotata Daday, 1897 (ref. ID; 1345); Megalotrocha semibullata Thorpe, 1889 (ref. ID; 1345, 2757, 3514); Sinantherina semibullata Harring, 1913 (ref. ID; 1345)
  4. Sinantherina socialis (Linne, 1758) (ref. ID; 1345, 1802, 1923, 2106, 2268, 2572, 2737, 3688) or (Linnaeus, 1758) (ref. ID; 2757) reported year? (ref. ID; 2640, 3451) reported author and year? (ref. ID; 1519, 3292)
    Syn; Hydra socialis Linne, 1758 (ref. ID; 3688); Lacinularia alboflavicans Cubitt, 1872 (ref. ID; 3688); Lacinularia socilais Schweigger, 1820 (ref. ID; 3688); Megalotrocha alboflavicans Ehrenberg, 1830 (ref. ID; 3688) or 1838 (ref. ID; 2757) reported author and year? (ref. ID; 2572); Megalotrocha flavicans Ehrenberg, 1838 (ref. ID; 3688); Stentor socialis Goldfuss, 1820 (ref. ID; 3688); Stentorina roeseli Bory de St. Vincent, 1826 (ref. ID; 3688); Voronkowia mirabilis Fadeew, 1925 (ref. ID; 3688); Vorticella socialis O.F. Muller, 1773 (ref. ID; 3688)
  5. Sinantherina spinosa (Thorpe, 1889) (ref. ID; 1324, 1345, 1831, 1847, 1923) or 1893 (ref. ID; 2545, 2715, 2737, 2757, 3180, 3508)
    Syn; Megalotrocha spinosa Thrope, 1893 (ref. ID; 1345, 2737, 2757, 3508); Sinantherina spinosa Harring, 1913 (ref. ID; 1345, 3508)
  6. Sinantherina triglandularis Arora, 1963 (ref. ID; 2737 original paper)

Sinantherina ariprepes Edmondson, 1939 (ref. ID; 1923, 2703, 2737, 2761 original paper, 3259, 3508)

Descriptions

This species has an oviferon consisting of 2 humps, and no warts. Colonies of S. ariprepes apparently grow by accretion aggregates of free-swimming larvae have not been seen (Edmondson 1939). (ref. ID; 1923)

Corona almost circular, with broad, fairly deep ventral notch, small dorsal gap, several times a wide as body; body slender, subcylindrical, strongly annulated; foot wide, conical, tapering to small, flat cuticular disc; lateral antennae on large folds of the cuticle, oviferon on dorsal side of foot, near anterior end, consisting of two hump-like folds of cuticle, with glands between; cloacal aperture between anterior ends of the two parts of oviferon; foot with several small lobes of hypodermis at tip, resembling closely the cement glands of ploimate species, with small cuticular projection on dorsal side near tip; large anterior salivary glands each with small pear-shaped accessory gland; sessile, forming small colonies. (ref. ID; 2761)

This species has one unpaired and eight paired gastric glands; 1) a large ovate pair on the lateral anterior surface of the stomach corresponding to the two gastric glands of most other rotifers 2) two very small pear-shaped glands near the large ones on the dorsal side of the stomach 3) two small elongate glands on the dorsal anterior side of the stomach, somewhat farther posterior than the large pair 4) a median, elongate gland on the mid-line of the ventral side of the stomach at the level of the large, ovate glands mentioned first 5 a pair of elongate glands on the lateral surface of the stomach near the posterior end. The elongate glands are cytoplasmic cylinders with a small number of nuclei arranged linearly. They seem to correspond to the supernumerary glands found in other Flosculariidae (Valkanov 1936). In addition to these definite structures, there are two lateral, thickened areas in the groove between the stomach and intestine. Sinantherina socialis and S. semibullata have nine definite glands also, but the details of shape and relative size are different. Apparently Wulfert (1939) was the fist to give an adequate account of the pairs numbered 3 and 5 above, although Ehrenberg (1838) figures and mentions the posterior pair. These have been called caeca (Blidsacke) but since they have no lumen this name seems inappropriate. The stomach itself in S. ariprepes is divided into two distinct chambers, an anterior part with thick, cellular walls and narrow lumen, and an ovate, posterior part with thin, ciliated, syncitial (?) walls and wide lumen. The posterior chamber is separated from the intestine which is similar in structure by a deep constriction. In this species colony formation does not seem to take place by the remarkable method of Sinantherina socialis which has been well described by Surface (1906). Instead of forming free-swimming colonies of immature individuals which all settle down at one location as if by common consent, the free-swimming young of S. ariprepes leave the colony singly and swim about alone. Evidently they may either eventually aggregate in small groups on the substrate, settle down alone, or enter established colonies. The explains the fact that the colonies are usually composed of less than two dozen individuals, often much less and on occasion may contain individuals of obviously rather different age. Under conditions of very rapid reproduction such as occurred in Boulder Lake large colonies may be built up, and these may be of homogeneous age composition for enough free-swimming young will be present at any moment to form large aggregations on the substrate. On one occasion a group of free-swimming individuals was seen together in a colony, but as the individuals seemed to be of fairly advanced age, and they were only loosely and irregularly attached together, it seems probable that this was not a true free-swimming colony, but a young sessile colony which had come loose from the substrate. Adult colonies are capable of slow locomotion if the twig to which they are attached is cut quite close to the colony on both sides. The attitude of the individuals varies and seems to depend on the size of the colony and reproductive state. In small colonies the foot is apt to be held partly contracted for long periods of time, especially just before an egg is laid. Such an individuals is shown by Edmondson (1939). Individual with an egg attached to the oviferon or those in very large colonies keep the foot well extended so that it is narrower than the body, and the shape is similar to that of normal S. socialis. All individuals actively sway from side to side and contract frequently, but those with resting eggs in the foot seem especially sensitive to shock, contracting on the slightest provocation, and are much slower to expand the corona again. The characteristic swaying movements are less extensively but more abrupt. (ref. ID; 3259)
  • Egg: The resting eggs are evidently too large to pass through the cloaca, for they are passed down into the foot, apparently breaking the oviduct. As many as four resting eggs have been seen in one individual. The foot muscles are generally unaffected by the presence of the eggs among them, but in very old animals with several eggs some of the muscles may become broken. Occasionally an egg is pushed anterior past the ovary into the thick corona. The resting eggs of Sinantherina socialis are also kept in the foot. (ref. ID; 3259)
  • Male: The male has close resemblance to that of S. socialis. There seems to be a cuticular ring at mid-length in the sperm duct. During copulation, the male attaches itself to the female on the foot or posterior part of the body with the cuticular ring pressed against the integument of the female. This lasts only a few seconds. The constant motion of the members of the colony prevented observation of the sperms themselves. Such hypodermic impregnation has been observed among the Ploima. The male has two large, spherical red eyes just below the surface of the apical area. Dorsal to the prominent cerebral ganglion is a clear sacular structure with a duct with extends forward but which could not be traced very far beyond the ganglion. The length of a newly hatched male is 240 µm. The male eggs are laid in clusters on the two lobes of the oviferon with may become considerably enlarged at this time. These eggs are 142x70 µm. (ref. ID; 3259)

    Comments

    Sinantherina ariprepes most closely resembles S. socilais from which it differs in the lack of warts and in the structure of the oviferon. Its occurs in small colonies of from five to twelve specimens. One solitary specimen was seen. Just before an egg is laid, the foot is strongly contracted which makes it considerably wider than the body. As the egg emerges from the cloaca it comes to lie between the two parts of the oviferon. Presumably only one egg can be carried at a time; no animals were seen carrying more. This is a very restless species, throwing itself about from side to side, rapidly contracting and expanding; its activity is broken by short periods of repose. (ref. ID; 2761)

    Measurements

    Length: total 685 µm. Width: corona 389, foot 130 µm (specimen slightly contacted). (ref. ID; 2761)

    Sinantherina procera (Thorpe, 1893) (ref. ID; 1847, 1923, 2703) or 1758 (ref. ID; 2737)

    Descriptions

    This species has 4 warts, but has a much longer and more slender foot than S. socialis. (ref. ID; 1923)

    Sinantherina semibullata (Thorpe, 1889) (ref. ID; 1345, 1923, 2545, 2572, 2619, 2715, 2737, 2757, 3514) reported author and year? (ref. ID; 3292)

    Synonym

    Megalotrocha binotata Daday, 1897 (ref. ID; 1345); Megalotrocha semibullata Thorpe, 1889 (ref. ID; 1345, 2757, 3514); Sinantherina semibullata Harring, 1913 (ref. ID; 1345)

    Descriptions

    This species is distinguished by 2 dark wartlike structures on the anterior part of the venter. (ref. ID; 1923)

    Colonial, members of the colony attached at their foot. S. semibullata has two wart like structures on the anterior part of the dorsum and has nine pairs of gastric glands. (ref. ID; 2715)

    Measurements

    Contracted specimen 600; egg 140/68 µm. (ref. ID; 2715)

    Sinantherina socialis (Linne, 1758) (ref. ID; 1345, 1802, 1923, 2106, 2268, 2572, 2737, 3688) or (Linnaeus, 1758) (ref. ID; 2757) reported year? (ref. ID; 2640, 3451) reported author and year? (ref. ID; 1519, 3292)

    Synonym

    Hydra socialis Linne, 1758 (ref. ID; 3688); Lacinularia alboflavicans Cubitt, 1872 (ref. ID; 3688); Lacinularia socilais Schweigger, 1820 (ref. ID; 3688); Megalotrocha alboflavicans Ehrenberg, 1830 (ref. ID; 3688) or 1838 (ref. ID; 2757) reported author and year? (ref. ID; 2572); Megalotrocha flavicans Ehrenberg, 1838 (ref. ID; 3688); Stentor socialis Goldfuss, 1820 (ref. ID; 3688); Stentorina roeseli Bory de St. Vincent, 1826 (ref. ID; 3688); Voronkowia mirabilis Fadeew, 1925 (ref. ID; 3688); Vorticella socialis O.F. Muller, 1773 (ref. ID; 3688)

    Descriptions

    Free-swimming colonies larvae may be distinguished by the presence of 4 dark, ovate, wartlike structures on the ventral anterior surface. The larvae do not carry eggs. The larvae aggregate into a spheric, free-swimming colony. After a period of exploring substrates, the colony disbands, and the individuals swim around in contact with the substrate. They then reaggregate and attach close together (Surface 1906). Thus the members of a colony are of nearly the same age. (ref. ID; 1923)

    Sinantherina spinosa (Thorpe, 1889) (ref. ID; 1324, 1345, 1831, 1847, 1923) or 1893 (ref. ID; 2545, 2715, 2737, 2757, 3180, 3508)

    Synonym

    Megalotrocha spinosa Thrope, 1893 (ref. ID; 1345, 2737, 2757, 3508); Sinantherina spinosa Harring, 1913 (ref. ID; 1345, 3508)

    Descriptions

    This species is distinguished by the presence of many fine spines on the venter. (ref. ID; 1923)

    Colonial, but in preserved state most of them are detached. Young ones and adult were seen in the same colony. Fine spines are present in the dorsum which is characteristic. (ref. ID; 2715)

    Free-swimming colonies consisting of adult and young individuals usually 20-40 in number. Fine thorn-like spines are present on the dorsum. The corona is circular, without any pouch-like structures on the inner margin. (ref. ID; 2737)

    Free-swimming colonies consisting of adult and young individuals, usually 20-40 in number (in the preserved condition, individuals usually detached). Fine thorn-like spines present on the dorsal side. Corona circular, without any pouch-like structures on the inner margin. (ref. ID; 3180)

    Measurements

    Length of contracted specimens 585; width 81 µm. (ref. ID; 2715)

    Length has been stated as 850 µm (Voigt 1957). But the adult forms in the colonies collected by me measures 405-675 µm in length and 78-117 µm in breadth. (ref. ID; 2737)

    Sinantherina triglandularis Arora, 1963 (ref. ID; 2737 original paper)

    Descriptions

    Free-swimming colonies consisting of young and adult individuals, about 20-40 in number per colony. The corona is kidney-shaped ad is broader than the body. There is a row of lashing cilia present all along the outer margin of the corona while the inner margin bears eight pouch-like structures-4 on either side of the median body-line. The corona if not carefully fixed shows lapette-like structures, but in a well-fixed specimen, is uniform. Warts are absent. The mastax is malleoramate with three prominent subunci among other smaller ones. The mastax cavity leads into a very short and narrow gullet which opens into the stomach. The stomach is made up of two parts-an anterior large sac- like portion and a small posterior rounded part. There are only three pairs of glands. A pair of small salivary glands which opens into the mastax cavity and two pairs of gastric glands. Of these, the anterior pair is larger and lies at the antero-dorsal side of the stomach. The posterior pair is smaller in size and also rests dorsal to the stomach. Touching the glands and lying dorsally on the anterior portion of the stomach, is a large germo-vitellarium. At the posterior end of the body and a little anterior to the foot is a pair of oviferons or egg carriers. (ref. ID; 2737)

    Comments

    This species does not agree is entirely with any of the five species. S. spinosa is characterised by the presence of thorn-like spines on the dorsum. S. semibullata has two dark wart-like structures on the anterior part of the dorsum and has 9 pairs of gastric glands. S. socialis has four dark wart-like structures and nine pairs of glands. In S. ariprepes warts are absent, but there are eight pairs of gastric glands and one unpaired gland. S. procera has four dark warts and four pairs of glands. S. triglandularis has no warts and there are only two pairs of gastric glands and one pair of salivary glands. The stomach is divided into two chambers as in S. ariprepes. Considering that the specimen does not agree with any of the known species, it represents a new species which is designated S. triglandularis. (ref. ID; 2737)

    Measurements

    Length of the body 260-572; breadth of the body 78-116; length of the egg 91-117; breadth of the egg 52-65; corona length 91-117; corona breadth 130-156 µm. (ref. ID; 2737)