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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Rousseletia

Rousseletia Harring, 1913 (= Rousselettia) (ref. ID; 2757)

ref. ID; 1663

Foot long with two toes. Eyespot present. Retrocerebral sac present. Mastax virgate. Body length 130 µm long. Single species. (ref. ID; 1663)

ref. ID; 1923

Uncus absent. Manubrium a slender forked rod. Littoral species. (ref. ID; 1923)

ref. ID; 3245

Notommatid rotifers with short, gibbous, illoricate body, with a slight constriction separation head and abdomen; the tail is large and collar-like, surrounding the base of the long, unjointed foot; the two toes are short and conical. The corona is slightly oblique; the marginal cilia are short except on two lateral, auricle-like areas; on the unciliated apical plate are two slightly decurved papillae; the mouth is near the ventral edge. The mastax is virgate and very large; the fulcrum expands fan-wise towards the posterior end and is in the transverse plane of the body; the rami are large and dome-shaped, without marginal denticulations; the mallei are simple, curved rods with a ventral spur; unci are absent; a rodshaped epipharynx, decurved at the ends, is imbedded in the anterior wall of the mastax. The retrocerebral sac is large and pyriform; no subcerebral glands are present. The eyespot is cervical. (ref. ID; 3245)
  1. Rousseletia corniculata Harring, 1913 (ref. ID; 1345, 1663, 1923, 3245) or 1914 (ref. ID; 2017)
  1. Rousselettia parrotti (Russell, 1947) (ref. ID; 2757)

Rousseletia corniculata Harring, 1913 (ref. ID; 1345, 1663, 1923, 3245) or 1914 (ref. ID; 2017)

Descriptions

The body is short, moderately stout and gibbous dorsally; its greatest width is nearly one third of the total length. The integument is very flexible, but the outline is quite constant. The entire body is colored green by simbiotic zoochlorellae. The head and abdomen are separated by a well marked constriction. The width of the head segment is nearly equal to its length, about two thirds of the greatest width of the body. The abdomen increase gradually in width for about two thirds of its length and is rounded posteriorly; a short, sleeve-like tail surrounds the base of the foot. The dorsal surface is marked with faint longitudinal striations, continued about half way down the sides. The foot is relatively long, slightly tapering and without joints. The toes are short, conical and acutely pointed; their length is about one twelfth of the total length. Only the ventral half of the truncate posterior end of the foot is occupied by the toes; on the dorsal margin is a minute papilla with a few long setae. The dorsal antenna is a small, setigerous pit in the normal position; the lateral antennae are on minute tubules, only a short distance above and in front of the tail. The corona is very slightly oblique; the circumapical band of cilia is without any dorsal gap and has laterally two strongly ciliated, auricle-like areas. The buccal field is evenly covered with very short cilia. On the unciliated apical plate are two conspicuous, slightly decurved papillae, resembling those of the genus Ploesoma. The mouth is near the ventral margin of the corona. The mastax is virgate and almost half as long as the body proper. The fulcrum is narrow at the base and its sides gradually diverge towards the posterior end, enclosing a thin, ovate lamella with fanshaped striations; it is unique on account of being in the transverse plane of the body. The rami are large and roughly triangular in ventral view; the edges are curved towards the dorsal side, so that a roughly dome-shaped cavity is formed. The mallei are simple, strongly curved rods, with a short spur near mid-length; there is no trace of the unci. The epipharynx is rod-shaped, with decurved ends. The piston is very large and fills the entire cavity of the mastax. The oesophagus is slender and moderately long. There is no constriction between the stomach and intestine. The gastric glands, ovary and bladder are normal. The foot glands are long and clubshaped. The retrocerebral organ consists of a large, pyriform sac, which never contains bacteroids; there are no subcerebral glands. The ganglion is large and saccate, and the small eyespot is at the posterior end. (ref. ID; 3245)

Measurements

Total length 130; toes 10; trophi 40 µm. (ref. ID; 3245)