Psolidium kermadeci, Davey, 2013

Davey, Nicola, 2013, The Psolidae of New Zealand and some additions to the Macquarie Ridge fauna (Echinodermata: Holothuroidea: Psolidae), Memoirs of Museum Victoria 70, pp. 51-67 : 62

Psolidium kermadeci sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:883E2AAC-C79C-

4145-9656-D41C50DA6A77

Table 1, Figures 2, 5C–D, 9A–D

Material examined. Holotype. New Zealand, Kermadec Trench : NIWA 72333 (1) Stn TAN0411/32, 35.36°S 178.52°E, 1425–1440 m, 07/03/2011.

Paratype. New Zealand, Kermadec Trench , NIWA 64441 (1) Stn TAN1007/51, 35.42°S 178.62°E, 1380–1545 m, 01/06/2010 .

Other material. Kermadec Trench: NIWA 49868 (1) Stn TAN0413/40, 36.96°S 177.29°E, 1652 m, 09/11/2004.

Description. Psolidium species up to 10 mm long, 4 mm wide, 3 mm high (preserved). Body form oval, profile dome-like with slightly raised oral and anal cones. Body wall scales macroscopically evident and continuous over domed dorsal and lateral surface, including oral and anal cones, largest scales up to 575 µm wide and 414 µm high, scale appearance glassy, beady, overall smooth, lacking any bumps or pillars. No discrete oral or anal valves or plates present, scales surrounding oral and anal cones reduced. Conspicuous dorsal tube feet evident, ranging from radial axis presence only through to several tube feet continuous onto interradials. Tentacles 10, 8 + 2 (ventral smaller). Sole distinct, calcareous, peripheral single row of tube feet, no smaller outer row, no midventral tube feet.

Dorsal ossicles are single-layered perforated scales, centrally some anastomosing, with tube feet holes evident, curved perforated support plates up to 55 µm wide. Ventral ossicles are thin-walled perforated plates with tiny blunt knobs, 3–4 perforations predominant, up to 125 µm long, perforations up to 40 µm wide.

Colour. Preserved: white.

Distribution. New Zealand, Kermadec Trench, 1380–1545 m.

Etymology. Named after Huon de Kermadec, an 18th century French navigator after whom the Kermadec islands were named, and eventually the Kermadec Trench, where the specimens were found.

Remarks. This description is based on two small specimens found in relatively close proximity to each other, at similar depths (> 1000 m). This is the first record of a Psolidium from the Kermadec Trench. Psolidium kermadeci sp. nov. is closest to the southern Australian species Psolidium granuliferum ( Clark, 1938) , but differs in possessing conspicuous tube feet dorsal and laterally. Also, like all other Australian Psolidium species, P. granuliferum is found in shallow depths, whereas P. kermadeci is one of the deepest occurring Psolidium species in the South Pacific region. This species also differs from the other New Zealand Psolidium species described in this paper as the dorsal tube feet are conspicuous and projecting through the body wall scales, whereas the other new Psolidium species require microscopic investigations to determine if such tube feet are present. Additionally, the sole ossicles are much thinner, have fewer perforations, and carry spinous knobs marginally.