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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Tetrasiphon

Tetrasiphon Ehrenberg, 1840

ref. ID; 1663

Lateral antennae located near base of foot, long, knobbed, and with excessively long setae. Ovary long, slender, and ribbon-like. Auricles absent. Dorsal antenna double and very long. Corona oblique. Retrocerebral sac present. Total length 750-1000 µm. Rare species in acid waters. (ref. ID; 1663)

ref. ID; 3245

Notommatid rotifers with fusiform, illoricate body, without constriction between head and abdomen; the tail is rudimentary; the foot is short and two-jointed, with two long, slender toes. The corona is an oblique, weakly ciliated area without auricles and used for carrying food to the mouth only, not for propulsion; the mouth is a little below the center of the corona. The antennae are long and tubular, the dorsal antenna double. The mastax is an aberrant form of the virgate type; the fulcrum is short and the rami very large and dome-shaped; the mallei are imperfectly developed. The epipharynx consists of four pieces of complicated form, which apparently serve to expand the mouth opening. The piston is very bulky, but weak; it is attached to the ventral floor of the mastax. The retrocerebral organ is well developed the subcerebral glands are longer than the sac. The eyespot is at the posterior end of the ganglion. (ref. ID; 3245)
  1. Tetrasiphon hydracora (ref. ID; 1861)
  2. Tetrasiphon hydrocora Ehrenberg, 1840 (ref. ID; 1345, 1663, 2017, 2593, 2757, 7846) reported year? (ref. ID; 2962)
    Syn; Copeus spicatus Hudson, 1885 (ref. ID; 2757) or Hudson & Gosse, 1886 (ref. ID; 1345); Notommata hydrocora Harring, 1913 (ref. ID; 1345); Notommata spicata Hudson, 1885 (ref. ID; 1345)

Tetrasiphon hydracora (ref. ID; 1861)

Descriptions

This species is characteristically found in soft waters. (ref. ID; 1861)

Tetrasiphon hydrocora Ehrenberg, 1840 (ref. ID; 1345, 1663, 2017, 2593, 2757, 7846) reported year? (ref. ID; 2962)

Synonym

Copeus spicatus Hudson, 1885 (ref. ID; 2757) or Hudson & Gosse, 1886 (ref. ID; 1345); Notommata hydrocora Harring, 1913 (ref. ID; 1345); Notommata spicata Hudson, 1885 (ref. ID; 1345)

Descriptions

The large, very sluggish animal has a fusiform body without a neck-fold in the stiff integument but did not possess the gelatinous case allegedly seen in older animals. The corona is oblique and has a prominent chin but very small auricles only. The retrocerebral organ is conspicuous, with two large subcerebral glands containing a bacteroid each. The eyespot is large and red and there are 5-7 small red spots on the distal end of the cerebral sack. The esophagus is very wide, the stomach large and sack-like usually containing undamaged Desmids and Diatoms obviously swallowed whole, as mentioned by Harring & Myers (1921). The gastric glands resemble peanuts. A constriction with glands leads to the intestine, there is a well developed protonephridial system and a large bladder. The ovary is characteristically band shaped with numerous small nuclei. A resting egg was seen next to the ovary in one specimens; the dark spherical interior is surrounded by a tough wavy shell. Summer eggs are spinous according to Hudson. The two dorsal and two lateral antennae are very long and knobby, carrying long setae. The most peculiar trophi are a combination of the virgate and incudate type. Harring & Myers (1921) give a very detailed description but their Figure does not clarify the rather complex situation. One can observe two superimposed structures in the living animal. The first one is incudate and sturdy with a short fulcrum. The second structure consists of thin lamellae forming a separate uncus and manubrium but has no ramus in the usual sense, just two broad plates forming a V-shape. This second structure is ventral from the first one in side view. As Tetrasiphon seems to swallow its foot whole, the role of this extremely complicated mastax is not clear. (ref. ID; 2593)

Measurements

Total length 900-950; width 95-105; toe 55 µm. (ref. ID; 2593)