Molpadiodemas neovillosus, 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 : 162

Molpadiodemas neovillosus sp. nov.

Table 3, Figures 5e–g , 6e–h , 8e, f

Pseudostichopus villosus Théel, 1886: 170–171 (part; syntype from Challenger stn 216 only; non Pseudostichopus villosus Théel, 1886 , lectotype designated below).

Material examined. Holotype. Syntype, P. villosus Théel, 1886 . Northern Pacific Ocean , Caroline Is, 2°56'N, 134°11'E, 3658 m, Challenger stn 216, 16 Feb 1875, BMNH 86.10 .2.151.

Paratypes. Galapagos Is, 2°34'N, 92°6'W, 2487 m, USNM 18275 (1) ; NMV F101847 (1) ; 4°33'S, 87°42'W, 3667 m, USNM 1008458 (1).

Other material. North Pacific Ocean , Mexico, S of Punta Maldonado, 3436 m, USNM 18276 (1).

Description. Up to 70 mm long; body rounded in transverse section, narrower anteriorly and posteriorly, lacking tubercles on pygal lobes, lacking brim; body wall thin, smooth, thicker and wrinkled if contracted, lacking globigerine or sponge spicule attachments; tube feet in conspicuous ventrolateral wide band, continuous anteriorly and pygally, feet cylindrical, frequently overlapping and matted, typically 1.6 mm long, 0.3 mm diameter; tube feet smaller, more spread, dorsally, smallest ventrally; broad, flat longitudinal muscles about 4.0 mm wide; multiple branching gonad tubules; ossicles in tentacles and gonads; tentacle ossicles abundant rods, variable form, predominantly thin, curved, smooth to rugose, not spinous, blunt to tapered, frequently intertwined at ends, rarely branched or with slight mid-rod swelling, some with lateral fused branches creating narrow mesh, rods up to 320 µm long; gonad ossicles abundant rods, predominantly thin, long, rarely branched, straight to slightly bent to irregular, rarely with slight swelling mid-rod, up to 350 Μm long.

Colour. Body and tube feet pale brown to off-white.

Etymology. From the Latin neo (new, recent), referring to this recently recognized new species with villous ventrolateral tube feet.

Distribution. Central Pacific Ocean, Caroline and Galapagos Is, Mexico, 2487–3667 m.

Remarks. Théel (1886) commented specificially on this specimen, noting that “the individual obtained at Station 216 is remarkable in that the pedicels of the dorsal surface and the sides of the body are slightly thicker and larger than those of the ventral surface which are thread-like and very minute”. Further to this comment is the observation that the tube feet are largest and most dense and frequently matted in a wide ventrolateral band which extends around the anterior and posterior ends of the body.

Amongst Molpadiodemas species, the distinguishing characters are: ventrolateral band of villous cylindrical tube feet that are distinctly smaller than those of the similar M. crinitus (above); tentacle ossicles predominantly thin curved rods with intertwined ends, some with slight swelling centrally; gonad ossicles abundant thin, short to very long, rods.

Figures

Figure 5. a–d, Meseres morbillus sp. nov., a, lateral view (USNM 1008093, paratype, 91 mm long); b, tentacles, ventrolateral tube feet “spotting” (NMV F101865); c, tentacles, digits (USNM E49243); d, calcareous ring (radial plate right half) (USNM 1008093, paratype). e–g, M. neovillosus sp. nov.; e, dorsal view (USNM 1008458, paratype, 71 mm long); f, pygal end, tube feet (USNM 1008458); g, ventrolateral tube feet (BMNH 86.10.2.151, holotype). h–k, M. pediculus sp. nov.; h, dorsal view, elongate form (USNM 1008318, holotype, 56 mm long); i, ventrolateral tube feet (NMV F104796, paratype); j, tentacles (holotype); k, broadly attached, relatively narrow, slightly thickened, longitudinal muscles (arrows) (paratype). l–m, M. porphyrus sp. nov. (USNM E38795, holotype, 114 mm long); l, dorsal view, thick rounded brim; m, gonad. n–o, M. translucens sp. nov. (USNM E48652, holotype, 78 mm long); n, dorsal view, longitudinal muscles visible through translucent body wall (arrows); o, tentacles.

Figure 6. Gonad ossicles (SEM). a–b, Meseres atlanticus (USNM E53278). c–d, M. helios sp. nov. (USNM E31106, holotype). e–h, M. neovillosus sp. nov. (USNM 1008458, paratype). i–l, M. porphyrus sp. nov. (USNM E38795, holotype). m–p, M. ustulatus sp. nov. (USNM 1022493, holotype).

Figure 8. Tentacle ossicles (SEM). a–d, Meseres morbillus sp. nov. (USNM E49251). e–f, M. neovillosus sp. nov. (USNM 1008458, paratype). g–h, M. pediculus sp. nov. (USNM 1008318, holotype). i–l, M. porphyrus sp. nov. (USNM E38795, holotype). m–p, M. translucens sp. nov. (USNM E48652, holotype). q–t, M. villosus, q–r (USNM E48640), s–t (USNM E9929). u–x, M. violaceus, u–v (USNM 1022608), w–x (USNM E49366).