Cucumaria dudexa O’Loughin & Manjón-Cabeza, 2009

O’Loughlin, Mark, Manjón-Cabeza, Eugenia & Ruiz, Francina Moya, 2009, Antarctic holothuroids from the Bellingshausen Sea, with descriptions of new species (Echinodermata: Holothuroidea), Zootaxa 2016, pp. 1-16 : 3-5

Cucumaria dudexa O’Loughin & Manjón-Cabeza sp. nov.

Figure 1a–c ; table 1.

Material examined. Holotype. East Bellingshausen Sea, R/V Hesperides , BENTART–2003, stn MB13B, 69.8223ºS, 77.8320ºW, 605 m, 15 Feb 2003, MNCN 29.04/125; tentacle ossicles slide NMV F161512; dorsal body ossicles slide F161513; ventral body ossicles slide F161514; dorsal body ossicles slide F161515.

Diagnosis. Specimen 35 mm long (tentacles withdrawn, preserved), sub-cylindrical, widest diameter 6 mm; thin, flexible, calcareous, parchment-like body wall; distinct sole ventrally, slight “belly”; upturned oral cone, rounded distally, 2 soft dorso-lateral oral papillae, 0.6 mm long; upturned long tapered anal cone, 18 mm long, thin and rounded distally, 5 soft radial anal papillae 0.6 mm long; 10 dendritic tentacles, ventral pair small; tube feet confined to radii, well-developed close paired series bordering sole latero-ventrally, slightly more spread series mid-ventrally, ventral interradii bare, smaller sparse radial tube feet on oral and anal cones; calcareous ring with 10 plates; radial plates anteriorly digitiform, thin, wide posteriorly with triangular notch; interradial plates anteriorly elongate, thin, tapered, wide posteriorly with curved indentation.

Ossicles in body wall slightly imbricate plates; ossicles single-layered, irregular, predominantly elongate, thick, smooth, perforated plates, few up to 24 large to small perforations, lacking surface and marginal knobs and spines, up to 400 µ m long; similar dorsally and ventrally; rare plates with digitiform denticulation and small perforations at one end. Tube feet with small endplates, 176 µ m diameter, small perforations centrally, marginally denticulate perforated support plates, not rods, up to 176 µ m long. Tentacles ossicles thick to thin, curved to bent to concave, round to oval, perforated plates, not rods, plates with blunt marginal denticulations, lacking surface knobs and spines, plates up to 208 µ m long.

Colour (preserved). Off-white.

Distribution. Antarctica , east Bellingshausen Sea, 605 m.

Etymology. From the Greek dudexa (twelve), to honour the Manjón-Cabeza family to whom this number is richly significant.

Remarks. This new Antarctic dendrochirotid species is referred to Cucumaria Blainville because it has: 10 dendritic tentacles, ventral pair smaller; tube feet confined to radii; calcareous ring lacking posterior composite projections, ring plates with narrowing anterior projection and posterior indentation; body wall ossicles single-layered perforated plates. Antarctic Cucumaria species described to date have been grouped by Gutt (1988) and Massin (1992) into the “ Cucumaria georgiana ( Lampert, 1886) group”. Cucumaria dudexa O’Loughin & Manjón-Cabeza sp. nov. shares with this group the combination of eight large and two small tentacles, radial tube foot distribution, and single-layered perforated plates in the body wall. Cucumaria dudexa O’Loughin & Manjón-Cabeza sp. nov. is distinguished from this group of species by the distinctive long thin tapered anal cone, presence of a discrete sole, and absence of knobs and spines on the perforated plate ossicles. Only a single specimen of Cucumaria dudexa sp. nov. was collected, but it is in very good condition and has distinct diagnostic characters.

Figures

FIGURE 1. a – c, Cucumaria dudexa O’Loughin & Manjón-Cabeza sp. nov.: a, holotype (MNCN 29.04 / 125), lateral view, oral end right, radial (left) and interradial plates of calcareous ring (insert); b, body wall ossicles (slides NMV F 161513, F 161514); c, tentacle ossicles (slide F 161512). d – f, Parathyonidium incertum Heding, 1954: d, lateral view, radial plate of calcareous ring (insert) (MNCN 29.04 / 126); e, body wall ossicles (slide F 161525); f, tentacle ossicles