Stolus sp.

Thandar, Ahmed S., 2008, Additions to the holothuroid fauna of the southern African temperate faunistic provinces, with descriptions of new species, Zootaxa 1697 (1), pp. 1-57 : 3-5

Stolus sp. indet.

Figure 1

Material examined

SAM-A27972, UCT Ecol. Surv., Van Veen, St. WCD 114 , off Saldanha Bay , WCP, 33º 6.5' S, 17º 32.9' E, 3.vii. 1961, 273 m, 1 spec.

Description

Specimen 16 mm long, 5 mm wide in mid-body. Colour uniformly yellowish-white, podia of same colouration. Mouth and anus terminal. Tentacles retracted, of same colouration as body wall, eight large, wellbranched, of unequal length, dorsal ones larger, mid-ventral two considerably reduced. No anal teeth or any special anal papillae detected. Podia numerous, papilliform, scattered, evenly distributed in ambulacra and interambulacra, suckers small, of same diameter as podia.

Calcareous ring ( Figure 1E ) poorly calcified, tubular, exceptionally long (11 mm), reaching posterior third of body, sub-divided into a mosaic. Polian vesicle single, considerably elongate, reaching level of cloaca; stone canal ( Figure 1D ) short, straight, madreporite pyriform. Most of gut lost, perhaps due to previous dissection, stomach highly muscular, gizzard-like. Respiratory trees well branched, right one reaching extreme anterior end, left one only anterior third of body but more profusely branched, both trees arising from common stem. Gonad immature, comprising two tufts of short, unbranched, whitish tubules attached in mid-body. Retractor muscles thin, arising from longitudinal bands in mid-body, more anteriorly in ventral ambulacra. Cloaca elongate.

Spicules of body wall sparse, comprising simple, single-layered, large-knobbed oval to irregular plates, 90- 96 µm, with 5-6 holes, mostly restricted to anal region ( Figure 1A ). Podia without deposits, end-plates also absent. Introvert deposits scarce, comprising large-knobbed plates ( Figure 1B ), up to 104 µm, lacking in distal part of introvert, scarce elsewhere. Tentacle stalk and tips comprising delicate, smooth, multilocular plates, of varying shapes and sizes, 54-113 µm ( Figure 1C ).

Distribution West coast of S.A., 273 m. Remarks

The single specimen perhaps represents a new species but because of its immaturity, poor calcification of the calcareous ring and the scarcity of spicules, it is here not treated as such. No species of Stolus has yet been described with such a scarcity of spicules but this may be due to the immaturity of the material. Thandar (2005) provides a key to the 13 nominal species currently classified in the genus but the present material is not referable to any of these.

Figures

FIGURE 1. Stolus sp. indet. (juvenile). SAM-A27972. A. Plates from posterior body wall; B. plate from introvert; C. plates from tentacle tip; D. stone canal and madreporite; E. part of calcareous ring (not fully calcified). A-C scale a.