Antarctic and Sub-Antarctic species of Psolidium Ludwig (Echinodermata: Holothuroidea: Psolidae) Author O’Loughlin, P. Mark Marine Biology Section, Museum Victoria, GPO Box 666, Melbourne, 3001, Victoria, Australia (email: pmo @ bigpond. net. au) email: pmo@bigpond. net.au Author Ahearn, Cynthia Department of Invertebrate Zoology, MRC- 163, National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington DC, 20013 - 7012, USA text Memoirs of Museum Victoria 2008 2008-12-31 65 23 42 https://museumsvictoria.com.au/collections-research/journals/memoirs-of-museum-victoria/volume-65-2008/pages-23-42/ journal article 10.24199/j.mmv.2008.65.2 1447-2554 10665899 Psolidium dorsipes Ludwig Figures 1c ; 4b Psolidium dorsipes Ludwig, 1886: 9–10 , pl. 2, fig. 9.— Ludwig, 1892: 349 .— Ludwig, 1894: 135 ( passim ).— Perrier, 1904: 16 .— Perrier, 1905: 48 , pl. 2 figs 5–15, text figs G-H.— Ekman, 1925: 112–13 , text fig. 26.— Deichmann, 1941: 142–44 , pl. 29 figs 1–12.— Deichmann, 1947 : 336–37.— Hickman, 1962: 60 .— Pawson, 1969: 38 , map 3.— Pawson and Valentine, 1981: 453 .— Lambert, 1996: 28–30 , table 1. Figure 3. Photos of preserved specimens of species of Psolidium Ludwig, 1886 (a, b, by Cynthia Ahearn; c-f, by Leon Altoff and Audrey Falconer). a, P. schnabelae sp. nov. , Prydz Bay, dorso-lateral (oral end right), 26 mm long, holotype SAM K2345. b–d, P. whittakeri sp. nov. : b, South Sandwich Is, ventral, 28 mm long, holotype USNM 1112365; c, Deception I., lateral, 28 mm long, NMV F104834; d, tentacles, specimen 28 mm long, NMV F104834. e, f, P. tenue Mortensen, 1925 , Prydz Bay, 28 mm long (two ventral small, bottom), NMV F107416; e, lateral; f, sole. Figure 4. Photos of ossicles of species of Psolidium Ludwig, 1886 (a, b, f, by Cynthia Ahearn; c–e, by Chris Rowley). a, P. disciformis ( Théel, 1886 ) , shallow cup (bottom centre left, 150 μ m long) and disc-like plates from sole, holotype BM(NH) [18]86.10.2.86. b, P. dorsipes Ludwig, 1886 , button (left, 90 μ m long) and cup from sole, USNM 1114251. c–e, P. emilyae sp. nov. , holotype SAM K2221: c, dorsal scale; d, dorsal tube foot support plates; e, crosses and plates from sole. f, P. incubans Ekman, 1925 , deep goblet-like dorsal cups, 70-90 μ m wide, 80-110 μ m high, BM(NH) 2008.3190. Material examined . South Atlantic Ocean , Argentina , Santa Cruz , E of Grande Bay , 92 m , USNM E2177 ( 2 specimens ); E of Cabo Virgenes , 101 m , USNM 1114251 (5) ; near Strait of Magellan , 66 m , 1114252 (1); Tierra del Fuego , Staten I. , E40823 (2); Cape Penas, 81 m , E40824 (2); R/V William Scoresby stn 834, Cape Virgenes, 0–38 m , BM(NH) 2008.3182 (1); Scotia Sea, E of Burdwood Bank , 419–483 m , E40825 (1). South Pacific Ocean , Chile , Strait of Magellan , 36 m , E2178 (4); Cape Froward , 82 m , USNM 1081593 (1). Diagnosis . Psolidium species up to 17 mm long; preserved form variably with low to high profile, short to elongate oval sole; dorsal and lateral scales conspicuous, smooth, up to 1.6 mm wide; dorsal and lateral tube feet conspicuous, numerous. Sole: outer peripheral single series of smaller tube feet; inner peripheral single to double series of larger tube feet; mid-ventral (sole) radial single to zig-zag to double series of tube feet. Dorsal ossicles: multi-layered plates (scales) thick, 0–2 canals and 0–2 marginal indentations for tube feet per scale; intergrade with large thick knobbed plates with developing secondary layers; perforated plates with thickenings (buttons), 100–150 μ m long, 3 to many perforations; thick smooth perforated plates, 150–200 μ m long; numerous shallow cups, oval, marginally with round knobs, biggest cups knobbed on cross and rim, 2 large central and 2 smaller end perforations, cups 40–60 μ m long. Sole ossicles: shallow cups, oval, 2 large central and 2 smaller end perforations, some imperfectly formed, variably finely knobbed on margin to thickly knobbed on margin and cross, cups 40–70 μ m long; thickly knobbed, regular, 4-holed buttons, 80-100 μ m long, some irregular, up to 150 μ m long; shallow concave perforated plates variably knobbed on surface and margin, up to 16 perforations, up to 200 μ m long. Distribution . Argentina (E of Grande Bay), Burdwood Bank, Falkland Is; Chile , Tierra del Fuego, Strait of Magellan; 10– 483 m. Remarks . One Psolidium dorsipes specimen ( USNM 1114251) has shallow cup-shaped indentations covering the sole that appear to indicate brood-protection under the body.