Zosterodasys debilis Alekperov, 1984

Vďačný, Peter & Tirjaková, Eva, 2012, Taxonomic revision of the ciliate genus Zosterodasys Deroux, 1978 (Protista: Ciliophora: Synhymeniida), Zootaxa 3345, pp. 34-58 : 46

Zosterodasys debilis Alekperov, 1984

( Figs 5 H–R)

Chilodontopsis debilis – Jankowski 2007: 729 (combining author).

Zosterodasys debilis Alekperov, 1984: 1251 , figs d, e; Fernandez-Leborans & Alekperov 1996: 10, fig. 8 (taxonomic revision); Asadullayeva & Alekperov 2007: 145, figs 3A, B (description of a Caspian population). Zosterodasys alizadei Aliev, 1990: 16 , fig. 2 I; Fernandez-Leborans & Alekperov 1996: 5, fig. 2 (taxonomic revision); Jankowski 2007: 729.

Diagnosis. Size about 60–90 × 40–50 µm in vivo. Body shape elliptical with left margin anteriorly more or less distinctly projecting. Macronucleus globular to ellipsoidal with a single globular to ellipsoidal micronucleus. A single large contractile vacuole usually occupying posterior body third. On average 35 ciliary rows: 20–25 ventral and 10–15 dorsal. Synhymenium incompletely encircles cell. On average 12 (10–13) nematodesmal rods. Freshwater.

Type locality. Plankton and periphyton of the Džejranbatanian [Dzejiranbatanian] water reservoir, Apšeronsk [Apsheronsk] Peninsula, Azerbaijan.

Type material. Alekperov (1984) deposited one syntype slide of Z. debilis (registration number DVB No. 53) in the Institute of Zoology, NAS of Azerbaijan, Baku City. Aliev (1990) did not mention the repository, where he deposited one holotype slide of Z. alizadei (registration number D-No. 309).

Etymology. Not given in the original description. The Latin adjective debil · is, - is, - e ([m, f, n]; weak, feeble) possibly refers to the small body size and the low number of the ciliary rows as well as of the nematodesmal rods.

Remarks. Jankowski (2007) transferred Z. debilis to Chilodontopsis due to the similarity with C. depressa . We do not support Jankowski’s combination because the synhymenium of Z. debilis is thickly ciliated and interrupts all ventral ciliary rows (vs. sparsely ciliated and not interrupting all ventral ciliary rows in C. depressa ; for authoritative redescription of the latter species, see Foissner et al. 1994).

We suggest to synonymize Z. alizadei with Z. debilis because diagnostic features used to differentiate Z. alizadei from Z. debilis are very similar or completely fall within the natural variability of the latter species as originally described and redescribed by Alekperov (1984) and Asadullayeva & Alekperov (2007). Specifically, this concerns the body size of fixed specimens (50–70 µm in Z. debilis and 65–70 µm in Z. alizadei ) and the number of the ciliary rows (35–45 in Z. debilis and 40–45 in Z. alizadei ) as well as of the nematodesmal rods (10–12 in Z. debilis and 12–13 in Z. alizadei ). Further, body shape and contractile vacuole as well as the nuclear pattern of both species match very well. Aliev (1990) discovered Z. alizadei in the benthos of the Džandar [Dzhandar] Lake, Kazah [Kazakh] Region, Azerbaijan at 18–20 °C, pH 7.5 and 8.9 mg /l O2.

Figures

FIGURE 5. Var i ou s Zosterodasys species and their supposed synonyms from life (F, G) and after protargol impregnation (A – E, H – R). (A – D) Chilodontopsis vorax, total ventral view of ciliary pattern (A), dorsal view of ciliary pattern in anterior body region (B), frontal view of oral opening (C), and nuclear apparatus (D). From Agamaliev (1967). (E) Zosterodasys agamalievi, total ventral view of ciliary pattern. From Kivimaki et al. (2009). (F, G) Chilodontopsis caudata, total ventral view. Length 70 µm. From Kahl (1933, 1935). (H, I) Zosterodasys debilis, total ventral view of ciliary pattern (H) and nuclear apparatus (I). From Alekperov (1984). (J – L) Zosterodasys debilis, total ventral view of ciliary pattern (J), dorsal view of ciliary pattern in anterior body region (K), and nuclear apparatus (L). From Fernandez-Leborans & Alekperov (1996). (M, N) Zosterodasys debilis, total ventral view of ciliary pattern (M) and nuclear apparatus (N). From Asadullayeva & Alekperov (2007). (O – R) Zosterodasys alizadei, total ventral (O) and dorsal (R) view of ciliary pattern and nuclear (P) as well as oral (Q) apparatus. From Aliev (1990).