Zosterodasys kryophilus Petz et al., 1995

Vďačný, Peter & Tirjaková, Eva, 2012, Taxonomic revision of the ciliate genus Zosterodasys Deroux, 1978 (Protista: Ciliophora: Synhymeniida), Zootaxa 3345, pp. 34-58 : 47-49

Zosterodasys kryophilus Petz et al., 1995

( Figs 7 A–G)

Zosterodasys kryophilus Petz et al., 1995: 59 , fig. 18; Jankowski 2007: 729; Wilbert & Song 2008: 980. Zosterodasys sp. – Agatha et al. 1993: 265, fig. 6.

Diagnosis. Size about 100–170 × 50–60 µm in vivo. Body shape obovate to elliptical with left margin anteriorly slightly projecting. Macronucleus ellipsoidal with a single globular micronucleus. About 6–9 contractile vacuoles evenly spaced along left postoral and posterior right body margin. On average 57 ciliary rows: 25–36 ventral and 21–33 dorsal. Synhymenium incompletely encircles cell. On average 22 (17–26) nematodesmal rods. Marine.

Type locality. Pancake sea ice of Weddell Sea, Antarctica, W7°19' S69°26'.

Type material. One holotype (syntype?) slide (registration number 2001/150) and one paratype slide (registration number 2001/54) with protargol-impregnated specimens were deposited in the Biology Centre of the Museum of Upper Austria, Linz (LI).

Etymology. Composite of the Greek noun krýos (κρύ⁰ς; frost, ice) and the Greek verb philein (φlƛεlν, to love), referring to the habitat in which the species was discovered.

Remarks. We tentatively suggest to affiliating the single specimen of Zosterodasys sp. found by Agatha et al. (1993) in the Arctic sea ice with Z. kryophilus . Both have a similar body size in protargol preparations (133 µm in Zosterodasys sp. and on average 150 µm in Zosterodasys kryophilus ) and number of the ciliary rows (about 40–50 in Zosterodasys sp. and 46–69 in Z. kryophilus ). The single seeming difference between them would be the number of the nematodesmal rods (17–26 in Z. kryophilus vs. 11 in Zosterodasys sp. according to the description of Agatha et al. 1993). However, according to the figure provided ( Fig. 7 E), the single specimen studied by Agatha et al. (1993) displays 16 nematodesmal rods, a value near the lower limit of Z. kryophilus . On the other hand, the conspicuously long preoral area of Zosterodasys sp. can be a rostrum, indicating that it is a misidentified Orthodonella apohamatus , a marine synhymeniid ciliate described by Lin et al. (2004). Therefore, data of Agatha et al. (1993) are not incorporated into the diagnosis of Z. kryophilus .

Figures

FIGURE 7. Vari o us Zosterodasys species and their supposed synonyms from life (A – C), after Heidenhain’s haematoxylin stain (H), and after protargol impregnation (D – G). (A – D, F, G) Zosterodasys kryophilus, ventral view of a representative specimen (A), lateral view showing dorsoventral flattening of the body (B), ventral view showing cortical granulation and contractile vacuole pattern (C), surface view of cortex showing a fibre bundle extending in parallel and right of the somatic kineties (D), ventral (F) and dorsal (G) view of ciliary pattern and nuclear apparatus. From Petz et al. (1995). (E) Zosterodasys sp., ventrolateral view of ciliary pattern and nuclear apparatus. This species is very likely a misidentified Orthodonella apohamatus, as indicated by the comparatively long preoral area, which can be a rostrum. From Agatha et al. (1993). (H) Zosterodasys acutus, ventral view of a representative specimen showing three contractile vacuoles (arrowheads) arranged in a row near right margin in posterior body half, a unique pattern as yet not found in any other Zosterodasys species. From Ozaki & Yagiu (1941). CV – contractile vacuoles, G – cortical granules.