Psolidium minutus (H. L. Clark)

O’Loughlin, P. Mark & Ahearn, Cynthia, 2008, Australian species of Psolidium Ludwig (Echinodermata: Holothuroidea: Psolidae), Memoirs of Museum Victoria 65, pp. 1-22 : 16

publication ID	https://doi.org/ 10.24199/j.mmv.2008.65.2
DOI	https://doi.org/10.5281/zenodo.8070642
persistent identifier	https://treatment.plazi.org/id/03FC87C9-5617-FFAD-A2AD-FA25FA0EF064
treatment provided by	Felipe
scientific name	Psolidium minutus (H. L. Clark)
status

Treatment

Psolidium minutus (H. L. Clark) View in CoL

Table 1, Figures 7c–d

Psolus minutus H. L. Clark, 1938: 507 View in CoL –09, figs 51–52.—H. L. Clark, 1946: 414.— Pawson, 1968b: 21 (key).— Cannon and Silver, 1987: 29.

Psolidium minutus.—Rowe View in CoL (in Rowe and Gates), 1995: 318.— Coleman, 2002: 65, fig.

Material examined. Paratypes: Lord Howe I, Neds Beach, under rock, Apr 1932, AM J6450 (3).

Other material. Neds Beach, under rock, N. Coleman, 20 Jul 2002, NMV F93176 View Materials View Materials (1) ; Middleton Reef, shallow reef front, 29°27.2'S 159°06.8'E, sandy bottom, 10 m, 4 Dec 1987, AM J20901 View Materials GoogleMaps (1).

Description. Psolidium species up to 10 mm long (live); dorsal and lateral body scales thick to thin, bluntly toothed on free edge, up to 1.3 mm wide; tube feet pass through scales.

Sole with peripheral band of tube feet, outer single series of smaller tube feet, inner single series; mid-ventral radial series of tube feet 2 wide.

Dorsal and lateral ossicles: single to multi-layered ossicles (scales) with tube foot canals; large cups shallow to deep, closely finely spinous rim, large cups 48–80 μ m long; small cupped crosses and cups deep, closely finely spinous distal arm branches and cup rim, small crosses and cups up to 24 μ m long; lacking rosettes.

Sole ossicles: perforated plates, irregularly round to elongate, smooth, marginally slightly knobbed to bluntly spinous, up to 36 perforations, up to 360 μ m long; shallow cups with finely spinous rim, typically 4 perforations, typically 48 μ m long; very small deeply cupped crosses and cups, finely closely spinous on distal arm branches and rim, up to 20 μ m long; lacking rosettes.

Tentacles lack rosettes.

Colour. Live colour white, tentacles yellowish (H. L. Clark, 1938; Coleman, 2002: 65, fig.).

Distribution. Tasman Sea, Lord Howe I, Middleton Reef; 1– 10 m.

Remarks. The distinctive characters of Psolidium minutus (H. L. Clark, 1938) are the presence of 2 size ranges of cupped crosses and cups in the sole, and absence of rosettes in the body wall. H. L. Clark (1938) noted that Dr Deichmann had called his attention to the fact that the ossicles in Psolus minutus resembled those in some species of Psolidium . Rowe (1995) reassigned Psolus minutus to Psolidium on the basis of dorsal tube feet penetrating the scales.