Cladodactyla brunspicula, Thandar, 2008

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 : 26-28

Cladodactyla brunspicula sp. nov.

Figure 10

Diagnosis

Small, gerkhin-like species, holotype 16 mm. Tentacles 10, equal. Anal teeth absent, papillae may be present. Podia confined to ambulacra, dorsally in 1-2 rows, ventrally large, in 2-4 rows, interambulacra naked. Polian vesicles 1-2. Spicules of body wall orange-brown to bronze in colour, comprising smooth, thin, multilocular plates with one end slightly prolonged into a roughened projection, dorsal plates 135-244 µm, ventral plates 123-175 µm, holes small, frequently occluded. Podia with smaller plates, end-plates absent. Tentacles with multilocular plates, introvert with rosettes.

Etymology The specific name refers to the brownish colouration of the spicules.

Material examined

Holotype (female), SAM A-22727, south Namaqualand , Jan 1964 . Paratype (juvenile), SAM A28010, UCT Ecol. Surv., Still Bay Shelf Transect , St. SST 72, 34 o 23.4' S, 21 o 26.5' E, 21.vi. 1972, 20 m.

Type locality Namaqualand, WCP, up to 20 m. Description of holotype (female)

Specimen small, gerkhin-like, slightly curved with transverse folds; body narrowing gradually towards anterior and posterior ends, ventral surface slightly flattened, dorsal conspicuously arched, sole absent. Length 16 mm, width in mid-body 5 mm. Colour in alcohol uniformly pale brown. Tentacles 10, retracted, more or less of same size, bushy, pale brown, speckled with dark spots. Mouth terminal, completely shut off; anus also terminal, encircled by five distinct radial papillae, no evidence of calcareous teeth. Podia confined to ambulacra, reaching level of mouth, pinkish, with well developed suckers, dorsal podia partially retracted, small, in double rows; ventral ambulacra set close together, podia large, in 2-4 rows, with four rows only in middle of mid-ventral ambulacrum, interambulacra naked. Body wall soft, thin, smooth to the touch.

Calcareous ring ( Figure 10F ) soft, poorly calcified; radial and interradial plates of approximately same length, separate, with wide gaps between them; radial plates truncate, slightly broad at base, deeply grooved on the outer surface for insertion of retractor muscle; interradial plates triangular with pointed apex. Polian vesicles ( Figure 10F ) two, sac-like, one on right of dorsal mesentery, other mid-ventral. Stone canal considerably short, straight, free; madreporite cauliflower-like with four lobes, situated immediately posterior to middorsal interradial plate of calcareous ring. Longitudinal muscles thin, unpaired; retractor muscles well developed, ventral series originating in anterior third of body, dorsal pair in posterior third of body. Respiratory trees, whitish, well branched, uniting before entering cloaca. Cloaca slightly elongate. Gonad as two tufts of moderately long tubules full of eggs. Podial ampullae conspicuous.

Spicules of dorsal and ventral body wall characteristically orange-brown to bronze in colour, of more or less similar form and size, comprising smooth, multilocular, flattened plates, slightly thickened in the middle, with smooth margins and with one end slightly prolonged and roughened with irregular projections; dorsal plates long ( Figure 10A ), 135-244 µm (mean 200 µm), narrow; ventral plates ( Figure 10B ) shorter, 123-175 µm (mean 149 µm); holes small, 6-18 dorsally, 7-13 ventrally, increasing in size and number towards extremities, often reduced to only a single series or frequently occluded, perhaps due to advancing age, hence less developed plates with larger holes. Anal body wall not characterized by any special deposits. Podia supported by similar but smaller plates/rods, 94-110 µm (mean 104 µm) and other, perhaps developing plates with fewer holes (2-7) and irregular margins; end-plates absent. Tentacles supported by usually elongate, 49-213 µm (mean 130 µm), multilocular plates with irregular margins ( Figure 10D ), of same colouration as those of body wall. Introvert with delicate rosettes, variously developed (15-50 µm, mean 28 µm) ( Figure 10E ).

Description of paratype

Paratype juvenile, twice as long as broad, length 3.5 mm, width in mid-body 1.75 mm. Mouth terminal, ventrally directed; anus dorsal. Colour in alcohol cream to pink. Tentacles retracted; anal papillae only observed on dissection. Podia confined to ambulacra, scarce, retracted, dorsally few with reduced suckers, ventrally in single rows in ventro-lateral ambulacra and most of mid-ventral ambulacrum, in double rows in middle of mid-ventral ambulacrum, end-plates absent. Interambulacra and most of dorsal surface naked.

Calacreous ring similar to that of holotype but plates meeting at base. Polian vesicle single, sac-like; madreporite tri-lobed. Gonad not developed. Body wall spicules of similar form, colouration and size as those of holotype, except that holes hardly show any signs of occlusion ( Figure 10G, H ). Plates of ventral body wall slightly knobbed with central axis thicker than rest of plate. Podial deposits ( Figure 10I ) as in holotype. Tentacle deposits ( Figure 10J ) incompletely developed, appearing as rods and developing plates. Introvert deposits not detected.

Distribution South-west coast of WCP, up to 20 m. Remarks

Although slight differences exist between the adult (holotype) and the juvenile (paratype), these are here considered as being age-related so there is no doubt that the two individuals are conspecific. The new species comes quite close to C. senegalensis Panning, 1955 differing from it in the equal size of the tentacles, fewer Polian vesicles, the lack of special branchings of the respiratory trees, the longer body wall spicules and the frequent occlusion of their holes. Equal tentacles and the paucity of dorsal podia occur in the type species C. crocea from the south-east Pacific but this species loses its spicules with age. The new species can also be referred to Hemioedema , as it is quite close to H. gruveli Hérouard , recently re-described by Massin (1993), differing from it in its shape, restriction of the podia to the radii, no specialised anal spicules and numerous body wall spicules. In any case, according to Panning (1949), both Cladodactyla and Hemioedema are closely related. In the form of its deposits, the new species also approaches the South African subtropical endemic, Pawsonellus africanus Thandar , but differs in the equal size of the tentacles, the colour of the spicules and the absence of rounded plates in the body wall. However, the new species appears restricted to the cold waters of the south-west coast of South Africa.

Figures

FIGURE 10. Cladodactyla brunspicula sp. nov. Holotype, SAM A 22727. A. Plates from dorsal body wall; B. plates from ventral body wall; C. rods from podia; D. plates from tentacle; E rosettes from tentacle; F. calcareous ring and associated structures (R-radial plate, IR-interradial plate, pv-polian vesicle. Paratype, SAM-A28010. G. Plates from dorsal body wall; H. plates of ventral body wall; I. rods of ventral podia; J. rods of tentacles. A-E & G-J scale a.