Stichopus horrens Selenka, 1867

Woo, Sau Pinn, Yasin, Zulfigar, Tan, Shau Hwai, Kajihara, Hiroshi & Fujita, Toshihiko, 2015, Sea cucumbers of the genus Stichopus Brandt, 1835 (Holothuroidea, Stichopodidae) in Straits of Malacca with description of a new species, ZooKeys 545, pp. 1-26 : 6

Taxon classification Animalia Aspidochirotida Stichopodidae

Stichopus horrens Selenka, 1867 Figs 6, 7

Stichopus horrens Selenka, 1867: 316; Panning 1944: 35; Loi and Sach 1963: 238, pl. 1, fig. B, C, pl. VI, Fig. 2; Cannon and Silver 1986: 27, figs 2d, 7g; Féral and Cherbonnier 1986: 96; Cherbonnier 1988: 147, fig. 61 A–P; Rowe and Gates 1995: 324; Gosliner et al. 1996: 281, fig. 1033; Byrne et al. 2010: 1077, fig. 2 A–D, fig. 3 B–D.

Stichopus godeffroyi Semper, 1868: 75, pl. 30, fig. 4; Sluiter 1901: 31.

Stichopus godeffroyi var. pygmaeus Semper, 1868: 75; Lampert 1885: 105; Ludwig 1888: 812.

Stichopus tropicalis Fisher, 1907: 676, pl. 70, fig. 1 a–i.

Material examined.

Four specimens: USM/MSL/PP001, USM/MSL/PP002, USM/MSL/PP003, USM/MSL/PP006.

Type locality.

Society Islands, French Polynesia

Description.

External morphology: Body slightly sub quadrangular in cross-section, with firm and rough surface; wrinkles on mid-dorsal area. Dominantly dark brown and yellowish in colour, with sporadic whitish-brown patches (Fig. 6). Papillae scattered across dorsal surface with larger papillae along dorso- and ventro-lateral areas; base of papillae dark grey, apex white. Ring of small papillae surrounding oral opening. Tube feet restricted in three ambulacra areas, with mid ambulacrum being wider with more rows of tube feet but a gap of lesser tube feet density in middle area of mid ambulacrum. Cream-white background colour with patches of brown dots across ventral body. Twenty peltate tentacles. Anus terminal.

Spicules: In dorsal body, numerous tables and C-shaped rods spicules. Tables in dorsal body with four central perforations, 9-21 peripheral holes around smooth-surfaced base; four pillars with moderate heights forming spires joined with one crossbeam, tip of spires with large spines (Figure 7 A–B). Spicules in dorsal papillae comprised of tack-liked tables, rods, C-shaped rods, and perforated plates (Fig. 7 C–F). Four pillars erected and fused at tips forming tall spire from middle of base (Fig. 7C). Large rods have rough surface and tiny spines on surface, especially at both ends; central perforations can be elaborate or simple (Fig. 7E). Perforated plates in papillae have jagged rims and 6-12 irregular holes; smaller in size than those of tube feet. Tube feet with large rods, multiperforated plates, and tables (Fig. 7 G–I). Large rods have central plate with perforations; rod surfaces rough and covered with spinelets (Fig. 7G). In tentacles, spicules consist of rods in different size and thickness (Fig. 7J). All rods have rough surface and spinelets; slight curves in larger rods while smaller appeared straight.

Remarks.

This species exhibits diverse body colours in specimens from different localities. Clark (1922) noted specimens from the Hawaiian Islands were dark olive-green, mottled with deep brownish-green in colour, which were not seen in specimens from the Torres Strait. Domantay (1953) remarked that the colour of this species changes with age. The species Stichopus horrens look very similar to Stichopus fusiformiossa sp. n. but are readily distinguishable by the presence of tack-like spicules on the papillae of Stichopus horrens and the absence of fusiform spicules on the tentacles in Stichopus horrens . Detailed characters distinguishing these species are provided in the section describing Stichopus fusiformiossa sp. n.

Distribution.

Society Islands, Galapagos, Indian Ocean, Bay of Bengal, South China Sea, Southern Japan, Papua New Guinea, Philippines, Australia, Hawaii to New Caledonia.