Ocnus capensis ( Théel, 1886 )

Thandar, Ahmed S., 2008, Additions to the holothuroid fauna of the southern African temperate faunistic provinces, with descriptions of new species, Zootaxa 1697 (1), pp. 1-57 : 18-19

Ocnus capensis ( Théel, 1886)

Cucumaria capensis Théel, 1886: 62 , pl.5, fig. 2 (non C. capensis Mitsukuri 1912 , non

Pseudocnus capensis Rho & Won, 1913 ).

Pentacta squamosa Cherbonnier, 1970:280 , text-fig. 1.

Ocnus capensis Thandar, 1991: 119 , figs. 4, 5 & 14b (syn. & records).

Pentacta capensis Rowe (in Rowe & Gates 1995, passim):271.

Type NHML.

Type locality Off Cape of Good Hope , 34 o 41'S, 18 o 36' E, 180 m.

Material examined

SAM-A27990, UCT Ecol. Surv., off Plettenberg Bay , St. SCD 177, 34 o 20' S, 23 o 31' E, 30.xi. 1960, 110 m, 1 spec.

Distribution South and south-west WCP, 155- 400 m.

Remarks

This characteristic deep-sea species, following Panning (1949), was referred to Ocnus by Thandar (1991). However, Panning (1962, passim), thought that the species may be referable to Pseudocnus , an opinion here disputed because of the presence in its body wall of usually complete baskets and the simplicity, therein, of the plates. Rowe (in Rowe & Gates 1995:271), on the other hand, thought that Théel’s species may be referable to Pentacta , a genus he suspected to be perhaps restricted to the southern African waters. However, he (Rowe, pers. comm.) now believes that the equal size of the tentacles is a generic character and would therefore prefer to consider Pentacta to be a monotypic South African genus, represented by only P. doliolum and that Théel’s species may still be an Ocnus , a genus perhaps extending from the European waters to the south west coast of South Africa. It is for this reason that, although O’Loughlin & O’ Hara (1992) consider Ocnus as most likely a European genus, Theel’s species is still here retained in Ocnus . It is another South African endemic, restricted to the deep cold temperate waters. Hence, all records of the species outside the southern African region, especially those from shallow, tropical waters ( Mitsukuri 1912 and Rohr & Won 1993), must be rejected as misidentifications, a view previously expressed by Thandar (1991) and supported by Natasen Moodley (2000). Thandar (op. cit.) also relegated Pentacta squamosa Cherbonnier, 1970 to the synonymy of O. capensis as he suspected that Cherbonnier’s material represented juvenile of this species. The current record from Plettenberg Bay is the most eastern yet recorded for the species.