Linostomella Aescht in Foissner, Berger & Schaumburg, 1999 (ref. ID; 4613)

Homonym Linostoma Jankowski, 1978 (ref. ID; 4613)

[ref. ID; 4613]
Linostoma Jankowski, 1978 is homonym, discovered by E. Aescht (pers. comm.); she replaced it by Linostomella nov. nom. For nomenclatural purposes the replacement name and the species have to be cited as "Linostomella Aescht in Foissner, Berger & Schaumburg, 1999". Linostomella is still monotypic and differs from Condylostoma by the lack of apical (frontal) cirri (membranelles). Such cirri are characteristic for marine species, but very likely also occur in some freshwater and soil condylostomids, for example, in Condylostoma terricola Foissner, 1995. (ref. ID; 4613)


Linostomella vorticella (Ehrenberg, 1833) Aescht nov. nom. nov. comb. (ref. ID; 4613 redescribed paper)
Syn; Bursaria vorticella Ehrenberg, 1833 (ref. ID; 4613); Condylostoma stagnale Wrzesniowski, 1870 (ref. ID; 4613)
Description; 1) Size in vivo about 100-210 x 70-160 um, usually around 150 x 100 um; Salzburg population 100-150 x 80-100 um. 2) Body saccular to ellipsoidal, both ends broadly rounded; ventral anterior half obliquely truncated, lateral view thus oviform to pyriform. 3) Macronucleus near mid-body, moniliform, composed of 2-15, usually 6-10 globular or ellipsoidal nodules. 4) Contractile vacuole in posterior end, with bulbous collecting canals extending to anterior body half. 5) Cortical granules colourless, about 1 um across, form distinct stripes between ciliary rows. 6) 26-45, usually 30-34 longitudinal to slightly spirally arranged ciliary rows. 7) Oral apparatus conspicuous, occupies anterior ventral half of cell, consist of question-mark shaped adoral zone of membranelles terminating near mod-body and conspicuous undulating membrane at right margin of buccal cavity. About 40-50 membranelles (only 19-22 according to Tuffrau 1968 and Dragesco 1970; different species? misobservation?). Peristomial bottom not ciliated but striated by very long microtubule arrays (oral ribs) originating from undulating membrane. 8) Restless, swims slowly to moderately rapidly. (ref. ID; 4613)
Comments; Traditionally, Linostomella vorticella was classified with the genus Condylostoma, which, however, has apical cirri. Several Linostomella vorticella-like condylostomids have been described from freshwater or saline inland waters: Condylostoma tardum Penard, 1922 (180-250 um) has only 3 macronuclear nodules; Condylostoma caudatum Lauterborn, 1908 is longish and posteriorly tapered; Condylostoma luteum Kahl, 1932 is more slender and has only 2 macronuclear nodules; Condylostoma nigra Dragesco, 1960 is slightly larger (180-300 um) and has blue cortical granules (like Stentor coeruleus); Condylostoma vorax Villeneuve-Brachon, 1940 is distinctly larger (250-400 um); Condylostoma kasymovi Alekperov, 1984 is longer (240-280 um), posteriorly tapered, and has more macronuclear nodules (15-17) and ciliary rows (65-70; like the C. vorticella population studied by Gelei 1954); Condylostoma terricola Foissner,1995 has apical cirri and has is a true Condylostoma, is usually more slender than L. vorticella, has distinctly fewer ciliary rows (15-18), and the macronuclear beads are longitudinally arranged. Climacostomum virens (Ehrenberg, 1838) Stein, 1859 lives benthically, is usually green due to symbiotic algae, and has a vermiform macronucleus. Easily confused with Bursaridium pseudobursaria (single reniform macronucleus) and contracted Stentor spp. (usually blue, red or black by distinct pigment granules), especially S. muelleri, which, however, usually does not occur in plankton. Pelagotrichidium faurei, a hypotrich, also has a very similar size and shape but possesses two widely separated macronuclear beads and conspicuous cirri. (ref. ID; 4613)