Condylostoma spatiosum Ozaki and Yagiu

Wilbert, Norbert & Song, Weibo, 2008, A further study on littoral ciliates (Protozoa, Ciliophora) near King George Island, Antarctica, with description of a new genus and seven new species, Journal of Natural History 42 (13 - 14), pp. 979-1012 : 990

Condylostoma spatiosum Ozaki and Yagiu in Yagiu, 1944

( Figures 10A, B )

This organism corresponds perfectly to both the original description ( Yagiu 1944) and those subsequently made by Shao et al. (2006). Hence only a brief description will be documented here.

Description

Cells in vivo about 400–600 Mm long, with a roomy triangular buccal cavity, which is consistently about one-third of body length. Cell basically colourless to slightly greyish or yellow-brownish when observed at low magnification. Macronucleus beaded, with about 15 fragments, located along right cell margin ( Figure 10A , arrow).

Adoral zone conspicuous, consisting of about 130 membranelles. Paroral membrane genus-typical, highly developed. The bases of two membrane-like frontal cirri conspicuously long, arranged in parallel or side-by-side at distal end of adoral zone. About 60 somatic kineties composed of densely arranged dikinetids, mostly extending over entire length of body, occasionally several kineties on ventral side strongly shortened or fragmented. One ventral suture recognizable at posterior portion of cell ( Figure 10B , arrowhead).

Remarks

This species was first mentioned at an annual meeting of Japanese zoologists in 1942 and cited later by Yagiu (1944) as Condylostoma spatiosum Ozaki and Yagiu in his subsequent descriptions. According to the regulations of ICZN (1999), the original (1942) report is nomenclaturally a nomen nudum because there were no available and formal descriptions/ publications to define that taxon. Hence the valid name of this species should be cited as Condylostoma spatiosum Ozaki and Yagiu in Yagiu, 1944 ( Shao et al. 2006). This organism is recognized by the combination of the arrangement of two membrane-like frontal cirri, the high number of somatic kineties, general body shape and size, marine habitat as well as the number of adoral membranelles ( Yagiu 1944; Shao et al. 2006).

Figures

Figure 10. Condylostoma spatiosum (A, B), Diophrys scutum (D), Diophrys aff. oligothrix (C, G), Diophrys appendiculata (E), Euplotes vannus (F) and Euplotes dragescoi nov. spec. (H–K) after protargol impregnation. (A) Dorsal view, to show the general appearance, arrow marks the beaded macronucleus. (B) Caudal portion, arrowhead marks the suture. (C) Dorsal view, to show the dorsal kineties (arrows). (D) Ventral view, to show the general infraciliature. (E) Ventral view, arrow marks the pre-transverse cirrus, double-arrowheads indicate the transverse cirri, while arrowhead points to the anterior marginal cirrus. (F) Dorsal view, arrowheads mark the three caudal cirri, arrow indicates the macronucleus. (G) Ventral view, arrow marks the pre-transverse cirrus. (H) Detail of a divider, arrowheads mark the newlyformed two marginal cirri (note the different sizes). (I) Dorsal view, to show the ridges. (J) Ventral view, arrow marks the anterior (large) marginal cirrus, double-arrowheads indicate the paroral membrane. (K) Detail of ventral view, arrow and arrowhead indicate the small and large marginal cirrus, respectively. Scale bars: 200 Mm (A); 100 Mm (D); 50 Mm (E–G, J).