Plesiocolochirus spinosus ( Quoy & Gaimard, 1834 )

O’Loughlin, P. Mark, Harding 1, Caroline & Paulay, Gustav, 2016, The sea cucumbers of Camden Sound in northwest Australia, including four new species (Echinodermata: Holothuroidea), Memoirs of Museum Victoria 75, pp. 7-52 : 24-27

Plesiocolochirus spinosus ( Quoy & Gaimard, 1834)

Figures 11 , 12

Holothuria spinosa Quoy & Gaimard, 1834: 118–120 , pl. 7 figs 1–10. Cladolabes spinosus.— Brandt, 1835: 74 . Stolus firmus Selenka, 1867: 356 , pl. 20 figs 118–119. Ocnus spinosus .— Semper, 1867: 55. Colochirus spinosus .— Selenka, 1868: 117.—von Marenzeller,

1881: 129–132.— Théel, 1886.— Lampert, 1889: 825–826. Thyone spinosa .— Semper, 1869: 238.— Lampert, 1885: 157. Stereoderma validum Bell, 1884: 150–151 , pl. 9 figs Ea–f.

(synonymy by H. L. Clark 1946) Apentacta spinosa .—H. L. Clark, 1946: 395. Plesiocolochirus spinosus .— Cherbonnier, 1946: 280–286, fig.— Rowe (in Rowe & Gates), 1995: 279.

Type locality. Australia, New South Wales, Port Jackson .

Material examined. S Queensland, Kimbla K4/69, -26.05 153.75 68 m, 1969, NMV F204081 (3); off Yeppoon, -24.05 151.45 9–37 m, 6 Sep 1967, NMV F204080 (1); off Yeppoon, Keppel Bay, -23.07 150.89 9 m, 6 Sep 1967, NMV F95257 (1).

Description. Body firm, packed with calcareous ossicles, fusiform with upturned oral and anal ends, long posterior taper, body oval in mid-body section, dorsal length shorter than ventral length, axial (not curved) length up to 64 mm; lateral edges of body with 3–12 firm conical papillae with large imbricating true scales, longest papillae mid-body, up to 6 mm long; five conical oral valves, each with two prominent spines distally, imbricating true scales distally; distal anal cone with large imbricating true scales, interspersed with small ossicle clumps; small anal scales; small ossicles clustered into contiguous lumps in mid-body to create pseudo-scales, each with central passage/perforation for withdrawn tube feet, pseudo-scales about 1.00 mm across. Ten dendritic tentacles, 8 large, 2 small. Calcareous ring cucumariid-like, plates solid, higher than broad, lacking posterior prolongations. Tube feet scattered irregularly over body, frequently withdrawn and inconspicuous, small, more numerous ventrally than dorsally, mid-ventral radius with irregular paired rows, narrow space on each side of mid-ventral radius lacking tube feet, tube feet appear to penetrate pseudo-scales.

Three inter-grading ossicle forms of body wall:

1. surface layer of finely knobbed bowls, oval to rounded rectangular in form, shallow concave, 4 central perforations, variable number of additional corner perforations, finely knobbed over surface, variably bridged from margins to sometimes create hollow, irregular, ellipsoid-like ossicles, 40–70 µm long;

2. layer of thickly knobbed buttons, flat, large marginal and central knobs, frequently 4 perforations but varying from 3–8, buttons 50–120 µm long, some buttons developing secondary layers to become small scales, up to about 216 µm long;

3. deeper layer of multi-layered scales, up to 1.5 mm long, developed from additional layers on knobbed plates.

Lateral papillae and tube feet with terminal endplates, fairly uniform perforations, about 120 µm.

Tentacle ossicles rods, lacking rosettes: large rods/rod-plates thick, curved, bent, perforated along rod, variable form, up to 480 µm long; small, irregularly-branched rods, some H-shaped, some distally perforate; fine very small distally perforate rods, not branched.

Live colour ( Cherbonnier 1946, based on Quoy & Gaimard 1834): red dorsally, grey ventrally, lateral spines purple, tentacles red with brown spots at the base of the trunks. Preserved colour (this work): off-white to pale brown with some residual red flecks, two broad irregular transverse dark brown bands around mid-body.

Distribution ( Rowe & Gates 1995). Eastern Australia, Queensland to Victoria, 9– 90 m.

Figures

Figure 11. Photos of preserved specimen of Plesiocolochirus spinosus (Quoy & Gaimard, 1834) (NMV F204081): a, dorso-lateral view; b, ventro-lateral view; c, inter-radial and radial plates of the calcareous ring; d, peri-anal view with imbricating scales.

Figure 12. Ossicles from specimen of Plesiocolochirus spinosus (Quoy & Gaimard, 1834) (NMV F204081): a, multi-layered scale ossicle from body wall, up to 1.5 mm long; b, body wall thick buttons, up to 120 µm long, and fine knobbed bowls with (top center) and without (bottom left) a bridge, up to 70 µm long; c, body wall bridged ellipsoid-like bowl (right), up to 70 µm long, and thick button (left).