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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Discotricha

Discotricha Tuffrau

[ref. ID; 1601]
Microthoracina with somatic cirri-like organelles, fusiform extrusomes, and wide-meshed silverline system. (ref. ID; 1601)

[ref. ID; 1618]
Ovate; papillae with trichocysts on dorsal and ventral surfaces, except the oral region; ventral surface ciliated, bearing nine rows of cirri in two fields; mouth toward left under a semi-rigid plate; contractile vacuole large, posterior; vacuolar pit large; macronucleus irregularly hemispherical; sand-dwelling. (ref. ID; 1618)
  1. Discotricha papillifera Tuffrau, 1954 (ref. ID; 2858, 4013) reported year? (ref. ID; 1618) reported author and year? (ref. ID; 191)

Discotricha papillifera Tuffrau, 1954 (ref. ID; 2858, 4013) reported year? (ref. ID; 1618) reported author and year? (ref. ID; 191)

Descriptions

Feed on diatoms. (ref. ID; 1618)
Discotricha papillifera invariably has nine kineties on the right side. On the left side, the ciliation is very sparse and most of the kinetids are unciliated, except those of the conspicuous frontal row. The dikinetids in kinety 2 are more irregularly arranged than depicted by Wicklow and Borror (1977) and those at the ends of kineties 3-6. The cytopharyngeal basket is circular and, like that of Lopezoterenia torpens, asymmetrical, i.e. its right half is formed by about eight fine rods while the left half consists of very fine fibres forming three to four digitate processes (rods?) at the pharyngeal opening. Adoral membranelles 1 is smaller than the membranelles 2 and 3, which invariably consist of three kineties, each comprising three basal bodies. There is a special field of fine, rod-shaped extrusomes (?) at the left margin of the central portion of somatic kinety 2. The extrusomes, located in conspicuous papillae, are nail-shaped, i.e. have a distinct head, at least after protargol impregnation. (ref. ID; 2858)
Discotricha papliifera is a marine interstitial ciliate. This species is a disc-shaped dorsoventrally flattened ciliate ranging from 40-50 um long, 35 um wide, and 5 um thick. Except for the outer rim, and buccal area on the left side of the cell just above the equator, the ventral surface is covered with curving rows of papillae. Between papillar rows are found variously sized and interrupted rows of somatic cirri: 4 long curving rows; 3 short caudal rows; and 2 post buccal rows. The buccal apparatus of D. papillifera appears somewhat like that of Tetrahymena, consisting of 3 membranelles and a paroral kinety. These may actually be "pseudomembranelles" such as are evident in Pseudomicrothorax, a microthoracine nassulid. The dorsal surface is completely covered with papillae except for the outer rim. Curving anteriorly on this rim, from the equator of the cell's right side around the left anterior edge, is a row of compound ciliary organelles, each composed of 2-6 cilia. Sparsely scattered in the papillar region of the dorsal surface are similar organelles made up of 2-4 cilia each. This ciliature resembles the dorsal bristles found in hypotrichs. Anteriorly and at the left margin of the ventrally located protoplasmic blade is found the paroral kinety, consisting of a double row of 4 kinetosomes. Posterior to and at the left of this kinety are the 1st and 2nd membranelles. The 3rd membranelles is almost completely hidden under the center of the protoplasmic blade; it is evident, however, in wet silver preparation, as well as in those examined in scanning and transmission electron microscopes. Another feature of the buccal apparatus is the presence of refractile rods extending from the protoplasmic blade anteriorly as demonstrable by light and electron microscopy. These rods are part of the cell's cytopharyngeal complex and are analagous to the cytopharyngeal "basket" of various cyrtophorine hypostomes. The single spherical macronucleus is located just above the equator in the medial axis of the cell and is visible in both Feulgen- and silver-stained preparations. A single micronucleus, located on the left anterior side of the macronucleus, is also visible in the latter preparations. The contractile vacuole is located in the left posterior part of the cell, with the contractile vacuole pore situated at the end of a nonciliated stomatogenic argentophilic ridge. (ref. ID; 4013)

Measurements

40 um long. (ref. ID; 1618)