Infraciliature and Cell Division of the Little Known Freshwater Ciliate Uroleptus cf. magnificus (Kahl, 1932) Olmo, 2000 (Hypotricha, Uroleptidae), and List of Published Names in Uroleptus Ehrenberg, 1831 and Paruroleptus Wenzel, 1953

In 1988, we found a large (250–400 × 80–150 μm in protargol preparations) Uroleptus-like hypotrich in a freshwater pond in Harbin, China. We studied the morphology of non-dividers and the cell division using protargol impregnation. Since we disregarded live observations and due to the lack of a modern revision of the uroleptids, a final identification was not possible. A detailed comparison with the most similar limnetic Uroleptus-like hypotrichs and with Rigidothrix goiseri revealed that the Chinese population is very likely identical with Uroleptus magnificus [basionym Holosticha (Paruroleptus) magnificus Kahl, 1932], a very rare species possibly confined to limnetic, stagnant water bodies of the holarctic region. Besides the large size, main features of U. cf. magnificus are: (i) about 80 adoral membranelles; (ii) three or four inconspicuous transverse cirri; (iii) 5–8 dorsomarginal kineties; (iv) the oral primordium originates de novo left of the postoral midventral cirri; (v) the frontal-ventral-transverse cirri anlagen of the proter and the opisthe originate via primary primordia; (vi) the left frontal cirrus of the proter originates from the middle portion of the disorganizing parental paroral; (vii) the parental endoral becomes the undulating membrane anlage for the proter; and (viii) the frontoterminal cirri originate in the plesiomorphic manner, that is, from the rearmost anlage. A compilation reveals that 59 species, subspecies, etc. have been described in or assigned to Uroleptus and Paruroleptus, but only about 50% of them seem to be true uroleptids. Many species of this predominantly limnetic group are little known.