Molpadiodemas ustulatus, 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 : 164

Molpadiodemas ustulatus sp. nov.

Figures 6m –p , 7a–c , 12q–t

Material examined. Holotype. South-east Pacific Ocean , Peru, Peru-Chile Trench, 8°48'S, 80°40'W, 5069–5173 m, RV Anton Bruun, Cr 11 stn 178, 3 Nov 1965, USNM 1022493 .

Paratypes. Type locality and date, USNM 1022566 (3) ; NMV F101858 (1).

Description. Up to 73 mm long; form cylindrical, narrowly elongate, slightly dorsoventrally depressed (possible artefact), lacking brim; outer body wall soft, pustulose, wrinkled; inner body wall soft, thin, semi-gelatinous; close cover of small cylindrical tube feet all over body, extended but not erect, longest and most evident in lateral band, not matted, up to 1.0 mm long, typically 0.6 mm long, 0.2 mm diameter; ossicles in tentacles and gonad; tentacle ossicles abundant smooth rods, thick to thin, straight to curved, some with central swellings, some with short branches, some with intertwined joined ends creating large and small perforations, some irregularly tuberous, up to at least 270 Μm long; gonad ossicles numerous thick to thin smooth rods, some lateral branches fused to form mesh with large perforations, fragments up to 280 Μm long.

Colour. Body and tube feet very dark brown.

Etymology. From the Latin ustulatus (scorched), referring to the dark brown blistered appearance of the specimens.

Distribution. South-east Pacific Ocean, Peru-Chile Trench, 5069–5173 m.

Remarks. The specimens are in poor condition, but adequate for establishing morphological diagnostic characters. Amongst Molpadiodemas species the distinguishing characters of M. ustulatus are: very dark brown colour; narrowly elongate body; tube feet most evident in lateral band; gonad rod ossicles with open lateral mesh.

Figures

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 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).

Figure 12. Gonad ossicles (SEM). a–d, Meseres villosus (USNM E9929). e–f, M. translucens sp. nov. (USNM E48652, holotype). g–h, Pseudostichopus peripatus, g (USNM 12198), h (USNM E48638). i–l, P. tuberosus sp. nov. (USNM E16721, holotype). m, P. aemulatus (USNM 1025525, paratype). Posterior lobe ossicles (compound microscope). n–p, P. hyalegerus, n–o (NMV F80181), p (NMV F80178). Tentacle ossicles (compound microscope). q–t, M. ustulatus sp. nov. (NMV F101858, paratype).