Psolidium marriotti, 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 : 62-64

Psolidium marriotti sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:EBEB19BA-C15D-

448A-86B8-EFBCF894E9FF

Table 1, Figures 2, 5E–F, 10A–E

Material examined. Holotype. New Zealand, Chatham Rise: NIWA 68137 (1) Stn N 857, 43.54°S 179.54°E, 399 m, 17/12/1976.

Paratypes. NIWA 76126 (3) same as holotype.

Other material. New Zealand, Hikurangi Margin : NIWA 76138 (1) Stn E 756, 42.02°S 174.44°E, 885 m, 30/03/1967 ; North Cape : NIWA 55513 (1) Stn TAN0906/83, 34.84°S 173.90°E, 136–138 m, 09/07/2009 ; NIWA 56813 (1) Stn TAN0906/164, 34.4°S 173.13°E, 145–149 m, 14/07/2009; NIWA 68427 (1) Stn F932, 34.44°S 173.12°E, 113 m, 15/10/1968. Macquarie Ridge , NIWA 40091 (1) Stn TAN0803/63, 52.48°S 160.41°E, 350–560 m, 09/04/2008 ; NIWA 68413 (2) Stn E228, 54.68°S 158.91°E, 148 m, 24/02/1965; NIWA 76250 (1) Stn C732A, 54.49°S 158.97°E, 220 m, 25/11/1961.

Description. Psolidium species up to 16 mm long, 5 mm high, 8.5 mm wide. Profile moderately high, rarely flat, anal and oral ends commonly raised slightly. No distinct oral or anal valves or plates; these are a continuation of small body wall scales. Dorsal and lateral scales visible and continuous over body wall, up to 3 mm wide but most commonly 1.5–2 mm wide, covered in conspicuous fine granules. Ventral margin scales significantly smaller, reaching a maximum of 0.7 mm wide; two rows surround ventral margin. Dorsal and lateral tube feet can be seen under a microscope on some specimens.

Sole transparent, naked midventrally, peripheral series of large tube feet in 1–2 scattered rows that sit on ventral margin; smaller series of tube feet not present. Tube feet do not consistently extend onto midventral radius, but sometimes up to six tube feet can be clustered on the midventral radius posteriorly and anteriorly; feet a maximum of 0.25 mm apart.

Dorsal and lateral ossicles large multilayered plates (scales) up to 0.2 mm long with tube foot canals up to 40 µm wide, anastomosing, with secondary layering, thickening and/ or heavy knobbing present marginally; single-layered plates with thickening, anastomosing and secondary layering also present, with few perforations, up to 190 µm long; tube foot support plates small thin, single-layered perforated plates with up to 18 perforations and up to 80 µm wide, plates curved up at opposing ends, perforations smaller on those upturned edges. Ventral ossicles single-layered perforated plates, surface generally heavily knobbed on one side, smooth on other surface, up to 24 perforations up to 125 Μ m wide, 2–4 larger central perforations (most commonly 2) with many smaller marginal perforations surrounding them, plate margins have blunt, rounded knobs; tentacle ossicles long rods up to 235 µm long, straight to curved to bent in shape, with perforations at either end but not through the middle; small thin, single-layered plates, variably flat or curved to form a ‘U’ shape, up to 80 µm wide with up to 14 perforations; larger less curved single-layered plates up to 125 µm long with up to 12 thicker, larger perforations.

Colour. Preserved: dark to light brown with a grey to white margin around scales.

Distribution. New Zealand: Hikurangi Margin, Chatham Rise, North Cape; Macquarie Ridge; 136– 885 m.

Etymology. Named for Peter Marriott, NIWA, who has provided the macro photos for this paper.

Remarks. Psolidium marriotti sp. nov. is similar to Psolidium aequm sp. nov., but is distinguished by the following characters: P. marriotti sp. nov. has an abundance of ventral ossicles, rounded and knobbed, with two larger central perforations and many small marginal perforations. In contrast, the ventral ossicles in P. aequm are sharper and more angular, with four larger central perforations. The tentacle rods of P. marriotti sp. nov. consistently have perforations through the middle and no blunt spines on the edges, whereas those of P. aequm sp. nov. only occasionally have perforations and always exhibit blunt edge spines. Additionally P. marriotti sp. nov. has no small, outer peripheral ventral tube feet. P. marriotti sp. nov. occurs at a shallower depth (135–885 m) than P. aequm sp. nov. (1040— 1059 m), and it has a much greater geographic range, from New Zealand’s North Cape southward to the Macquarie Ridge.