Pseudostichopus echinatus Thandar, 1992

THANDAR, AHMED S., 2007, Additions to the aspidochirotid, molpadid and apodid holothuroids (Echinodermata: Holothuroidea) from the east coast of southern Africa, with descriptions of new species, Zootaxa 1414 (1), pp. 1-62 : 6-7

Pseudostichopus echinatus Thandar, 1992

Pseudostichopus (Pseudostichopus) sp. Heding, 1940:360, text-fig. 6.

Pseudostichopus echinatus Thandar, 1992: 164 , fig. 2; O’Loughlin & Ahearn, 2005:170.

Type SAM, A23435 .

Type locality Off KZN coast, South Africa, 28° 21.9' S, 32° 34.6', 775–825 m.

Previous southern African record Type locality only.

Material examined

SAM-A27917 , off Tongaat Bluff, northern KZN, 29° 43.5' S, 31° 27.0' E , NMDP, St. ZV 2, 20 vi 1989, 235 m., 1 spec.

Diagnosis (from Thandar 1992, O’Loughlin & Ahearn 2005, amended herein)

Medium-sized species up to 65 mm long. Body wall encrusted with pointed shells, foraminiferans, sand grains, epizoons, etc. Tentacles about 20. Podia mostly in ambulacra of ventral surface, smaller and scattered dorsally but some dorso-lateral ones often more prominent. Stone canal rudimentary or absent. Spicules restricted to tentacles, in the form of large (up to 300 µm), irregular, closely knobbed or somewhat spinous rods, often perforated and sometimes developed as plates in young individuals; reduced in podia. Body wall, respiratory trees, longitudinal muscles and gonad without spicules.

Description

Specimen partially eviscerated. Length 37 mm, breadth in mid-body 7 mm. Colour in alcohol dull greyishbrown. Form cylindrical, mouth ventral, situated some distance from anterior end. Tentacles 17, retracted, white, peltate. Anus subventral, pygal furrow conspicuous, anal papillae or teeth absent. Body wall remarkably thin with usual encrustations. Podia non-retractile, better developed in the ventro-lateral ambulacra, shorter and scattered dorsally and in mid-ventral ambulacrum; suckers not well defined, occasionally with reduced end-plates.

Calcareous ring damaged, radial and interradial plates similar to those of holotype (see Thandar 1992: fig. 2B). Polian vesicle sac-like; stone canal not detected; longitudinal muscles unpaired. Right respiratory tree longer than left, reaching mid-body but left more conspicuously branched. Gonad (testis) as two tufts of unbranched tubules.

Spicules confined to tentacles and as reduced (56–90 µm) end-plates in some podia. Tentacle spicules as slightly curved, often perforated rods, 133–274 µm long (mean 189 µm), with minute knobs and/or spines, occasionally with branched ends and/or developed as plate-like structures.

Distribution West Indian Ocean, 235– 825 m.

Habitat Fine, soft mud.

Remarks

This is the second record of this species from the South African east coast. The current specimen differs from the holotype in its more cylindrical body form, presence of rudimentary/reduced end-plates in some podia and less-heavily knobbed rods and plate-like rods in the tentacles. In other features it resembles the type so strongly that the differences are here considered intraspecific variations, perhaps due to age (37 mm cf. 65 mm for the holotype) or the depth at which the present specimen was taken (235 m cf. 775–825 m for the holotype). Thandar (1992) compared this species with several related congenors..