Molpadiodemas crinitus, O'Loughlin & Ahearn, 2005

O'Loughlin, P. Mark & Ahearn, Cynthia, 2005, A review of pygal-furrowed Synallactidae (Echinodermata: Holothuroidea), with new species from the Antarctic, Atlantic and Pacific oceans, Memoirs of Museum Victoria 62 (2), pp. 147-179 : 157-158

Molpadiodemas crinitus sp. nov.

Figures 1h , 3f, g , 4e–h , 7h

Pseudostichopus sp. MoV 2033.— O’Loughlin et al., 1994:

253–254.

Meseres villosus .— O’Loughlin, 2002: 313, figs 3a, b, tables 1, 2

(non Pseudostichopus villosus Théel, 1886 ).

Material examined. Holotype. Eastern Antarctica, Ross Sea, 72°57'S, 171°35'E, 573–576 m, USARP, Eltanin stn 1878, USNM 1023615 .

Paratypes. Type locality and date, USNM E48644 (8) ; NMV F101872 (3).

Other material. Eastern Antarctica, Prydz Bay , 66°46'– 68°50'S, 72°14'– 77°19'E, 333–765 m , NMV F68152 (9); F68158 (1); F68162 (5); F72534 (2); F76583 (2); F76597 (1); F76606 (1); F81816– F81817 (3); Ross Sea , 67°24'– 78°23'S, 166°15'E – 163°02'W, 223–923 m , USNM E48578 – E48580 (8); E48597 (4); E48621, E48623 (4); E48642 (6); E48646 (9); NMV F101874 (3); USNM E48662 , E48663 (32); NMV F101873 (4); E49244– E49245 (12); E49270 (1); E49283 (1); E49286 (2); E49299– E49300 (3); E49368 (1); 1005125 (1); 1005129 (2); New Zealand, Antipodes Is , Campbell Plateau, 2010–2100 m , E48655 (2); W of Antipodes Is , 103 m , E49357 (4).

Description. Up to 150 mm long; body rounded in transverse section, lacking brim and distinctive ventrolateral margin, sometimes transverse grooves, frequently tubercles and pygal sublobes posteriorly; body wall firm, thick to thin; lacking significant globigerine or sponge spicule attachments; body covered with thick, cylindrical tube feet, typically extended, longest and often matted pygally and in a conspicuous lateral to ventrolateral band, feet typically 2.0 mm long, 0.4 mm diameter, up to 3.0 mm long, smaller and more spaced dorsally and ventrally; multiple-branching gonad tubules; ossicles in tentacles only, abundant to sparse to absent, thick irregular non-spinous rods, frequently short thick rods with bluntly rounded ends, some with swelling mid-rod, some as irregular tuberous lumps, some with short branching, some with blunt spines, some ends branched, some branches intertwined to create perforations, lace-like mesh development on rods rare, rods up to 270 Μm long.

Colour. Body and tube feet similar in colour, dark to pale brown, contracted tube feet rare and sometimes with dark discs.

Etymology. From the Latin crinitus (long-haired, fringed), referring to the lateral band of long, fringing tube feet.

Distribution. Eastern Antarctica, Prydz Bay, 333–765 m ( O'Loughlin, 2002, as Meseres villosus ); Ross Sea, 223–923 m; Antipodes Is, 103–2100 m (this paper).

Remarks. O’Loughlin (2002) considered Antarctic material to be Pseudostichopus villosus , and although it is similar in form it is not conspecific with any of the syntypes assigned to P. villosus by Théel (1886). Amongst Molpadiodemas species the distinguishing characters of M. crinitus are: wide ventrolateral band of thick, cylindrical, extended, sometimes matted tube feet, similar in colour to the body wall, typically 2.0 mm, long, 0.4 mm diameter; tentacle ossicles usually abundant, frequently short thick rods rounded distally; absence of gonad ossicles.

Figures

Figure 1. Characters of pygal-furrowed Synallactidae. a, ventral mouth and anus (M. helios sp. nov., USNM E31104, paratype, 91 mm long); b, ventral peltate tentacles, polian vesicle (P. mollis, TM H2004; anterior end dissected off); c, respiratory tree (P. mollis, TM H2004); d, drawing of dorsal posterior pygal furrow; e, posterioventral view of pygal furrow and anus (M. violaceus, BMNH 86.10.2.150); f, anterior dorsal madreporite (arrow) (P. peripatus, USNM 1008159); g, drawing of calcareous ring (radial plate right, as in P. spiculiferus); h, calcareous ring (M. crinitus sp. nov., USNM E48644, paratype); i, calcareous ring (M. violaceus, BMNH 86.10.2.145).

Figure 3. a–b, M. atlanticus (NMV F101845, 210 mm long); a, ventral view; b, small epibiotes on body wall. c–e, M. constrictus sp. nov. (USNM 1022815, paratypes); c, dorsal view (51 mm long); d, ventral view (51 mm long); e, tube feet. f–g, M. crinitus sp. nov. (USNM 1023615, holotype, 96 mm long); f, ventral view; g, ventrolateral tube feet. h, M. depressus, pygal furrow, gelatinous body, lateral brim (NMV F101849). i–k, M. epibiotus sp. nov. (USNM 1008183, holotype, 110 mm long); i, ventral view, posterior taper; j, ventral mouth, epibiote concavities (arrows); k, ventral view, epibiote concavity (left arrow), few tube feet (central arrow). l, M. helios sp. nov., tentacle digits, tube feet (lower right) (USNM E31104, paratype). m–o, M. involutus (NMV F101850, 40 mm long); m, ventral view, serrated margin; n, dorsal anterior view, globigerines attached; o, posterior ventrolateral tube feet.

Figure 4. Tentacle ossicles (SEM). a–d, Meseres atlanticus, a–c (USNM E49466), d (USNM 1020067). e–h, M. crinitus sp. nov. (USNM E48662). i–l, M. depressus (USNM E53279). m–p, M. epibiotus sp. nov. (USNM 1008310, paratype). q–t, M. helios sp. nov., q–r (USNM E31104, paratype), s–t (USNM E31117, paratype). u–x, M. involutus (USNM E49256).

Figure 7. a–c, Meseres ustulatus sp. nov.; a, ventral view (USNM 1022566, paratype, 55 mm long); b, ventrolateral tube feet (USNM 1022493, holotype); c, tube feet (NMV F101858, paratype). d–f, M. villosus; d, ventral view (BMNH 86.10.2.147, lectotype, 90 mm long); e, ventrolateral tube feet (lectotype); f, posterior tube feet (NMV F98745). g–i, M. violaceus (BMNH 86.10.2.156, holotype, 142 mm long); g, ventrolateral view; h, tube feet of M. crinitus (left, NMV F101872, paratype) contrasted with M. violaceus (right, NMV F101848); i, tentacles (USNM 1022608).