Molpadiodemas pediculus, 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 : 162-163

Molpadiodemas pediculus sp. nov.

Figures 5h–k , 8g –h

Material examined. Holotype. South Atlantic Ocean , NE of South Sandwich Is, 55°07'S, 25°59'W, 5435–5453 m, RV Eltanin, Cr 8 stn 591, 29 Apr 1963, USNM 1008318 .

Paratypes. Type locality and date, NMV F104796 (1).

Other material. Scotia Sea , N of South Orkney I., 2800 m, USNM E48635 (1).

Description. Up to 60 mm long; body small, rounded in section, elongate, tapered anteriorly and posteriorly, lacking brim; body wall firm, semi-gelatinous, surface smooth, not covered with attachments; tube feet all over body, overlapping ventrolaterally, distinctly cylindrical, frequently erect, close cover, anteriorly and pygally, typically 1.0 mm long, 0.25 mm diameter, up to 1.5 mm long; tube feet typically shorter, more thread-like, dorsally and ventrally than ventrolaterally; longitudinal muscles broadly attached, relatively narrow, slightly thickened; some unbranched gonad tubules; ossicles in tentacles only, predominantly irregular, thick, rough to smooth, sometimes bluntly spinous rods, swollen mid-rod, tapering at ends, rare branches joined to create thick intertwining mesh, sometimes irregularly tuberous, up to 280 Μm long.

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

Etymology. From the Latin pediculus (little foot), referring to the prominent ventrolateral band of small tube feet.

Distribution. South Atlantic Ocean, off South Sandwich and South Orkney Is, 2800–5453 m.

Remarks. Amongst Molpadiodemas species, the distinguishing characters are: body tapering orally and anally; close cylindrical tube feet overlapping ventrolaterally; longitudinal muscles broadly attached, relatively narrow, slightly thickened.

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 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).