Massinium vimsi O’Loughlin, 2012

O’Loughlin, P. Mark, Barmos, Shari & VandenSpiegel, Didier, 2012, The phyllophorid sea cucumbers of southern Australia (Echinodermata: Holothuroidea: Dendrochirotida: Phyllophoridae), Memoirs of Museum Victoria 69, pp. 269-308 : 290-292

Massinium vimsi O’Loughlin sp. nov.

Figures 13b , 15

Material examined. Holotype. Australia, eastern Bass Strait , VIMS, NZOI RV Tangaroa 81–T–1 stn 174, 39º16.8'S 147º32.2'E, 57 m, mud / shell, 18 Nov 1981, NMV F76629 .

Diagnosis. Massinium species 12 mm long, 5 mm diameter (preserved, tentacles withdrawn), form cylindrical with rounded ends, soft body wall; exterior anal scales not detected; 20 tentacles, 5 pairs of large, 5 pairs of very small; complete cover of tube feet, more prominent ventrally, up to 0.2 mm diameter; tubular composite calcareous ring 9 mm long, plates up to 1 mm wide, posterior radial notch, posterior deep inter-radial indentation closed posteriorly by continuous band of small plates to create elongate non-calcareous space; radials tapered anteriorly with anterior notch; inter-radials tapered to anterior point; single tubular polian vesicle; stone canal and madreporite lying anteriorly on calcareous ring; cylindrical longitudinal muscles, not divided; lacking gonad tubules.

Lacking mid-body wall ossicles; tube feet endplates up to 184 µ m diameter with irregular small perforations and slightly undulating to denticulate margin, rod-like support plates around margin of endplates, narrow, curved, perforations distally, sometimes along rod, large central, small distal, rods up to 96 µ m long; peri-oral region with tables, discs up to 72 µ m long, lobed margin, up to about 18 perforations, spires about 32 µ m long, 2 pillars each with 2–3 sometimes bifid spines distally, single crossbridge; introvert ossicles endplates, endplate support rods and rosettes, endplates up to 136 µ m diameter with irregular small perforations, rods up to 80 µ m long, straight to slightly bracket-shaped, slightly swollen distally with 1–2 terminal perforations, rosettes rare; tentacles ossicles rods and rare rosettes, rods up to 96 µ m long, curved, ends of rods swollen, smooth or denticulate, 1–2 distal perforations; anal ossicles endplates and endplate support rods, anal endplates up to 144 µ m diameter, undulating margin, some with slightly larger peripheral perforations, support rods perforated as in tube feet, up to 80 µ m long.

Colour (preserved). Body pale brown; tentacles dark brown.

Type locality and distribution. Southeast Australia, eastern Bass Strait, 57 m.

Etymology. Named for the former Victorian Institute of Marine Sciences (VIMS), with appreciation of the thoroughness of the 1981 benthic survey of eastern Bass Strait with a significant contribution of specimens to this study.

Remarks. Massinium vimsi O’Loughlin sp. nov. is erected for a single specimen in good condition. The small specimen size and absence of gonad tubules suggest that it is probably a juvenile. The type locality is unlikely to be sampled again in the foreseeable future and we judge that it is important to erect this species. The distinguishing combination of diagnostic characters for Massinium vimsi O’Loughlin is given in the key (above).

Figures

Figure 13. Photos of preserved specimens. a, Massinium melanieae O’Loughlin sp. nov. (holotype NMV F174897); b, Massinium vimsi O’Loughlin sp. nov. (holotype, NMV F76629) (insert: form of the calcareous ring plates); c, Massinium watsonae O’Loughlin sp. nov. (holotype, NMV F97435); d, calcareous ring, stone canal (along alimentary canal) and madreporite, and 2 polian vesicles (top left corner) of Massinium watsonae (TMAG H1988); e, colour morph of Massinium watsonae (NMV F174899) (insert: form of the calcareous ring plates); f, exceptional calcareous ring from specimen of Phyllophorella thyonoides (H. L. Clark, 1938) with posterior prolongations joined as in Massinium species (WAM Z31975) (insert: form of the calcareous ring plates).

Figure 15. SEM images of ossicles from holotype of Massinium vimsi O’Loughlin sp. nov. (NMV F76629). Tube foot endplate (left); tentacle rods (right); (insert: drawings of table disc, developing disc, and table spire from peri-oral body wall table ossicles).