Holothuria (Theelothuria) pseudonotabilis, Thandar, 2007

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 : 40-42

Holothuria (Theelothuria) pseudonotabilis sp. nov.

Figure 18

Diagnosis

Perhaps a small species, holotype 59 mm long. Colour, in alcohol, an admixture of browns, dorsum with eight pairs of dark blotches, whitish areas around bases of scattered tubefeet. Cuvierian tubules present. Body wall tables few, of three types: commonest type with circular to subcircular, slightly spinose to smooth disc (40–75 µm), low spire (20–50 µm) terminating in ring of about six blunt teeth, rarely rim knobbed or tables modified to fenestrated spheres; second type commoner than third and of Mesothuria type with smooth disc (ca. 60 µm) with 6–7 large marginal holes and spire terminating in compact, often tripartite cluster of teeth; third type rare, disc oblong, up to 100 µm, with 2–3 series of holes, smaller marginally. Buttons numerous, slightly knobbed, 30–60 µm, holes often occluded.

Etymology The new species is so named as it was initially thought to represent H. notabilis Ludwig.

Type SAM-A27943 ; Inhaca Island , Mozambique, vi. 1971, B. Kensley .

Type locality Inhaca Island , Mozambique .

Material examined Holotype only.

Description

Specimen small, badly contracted, 59 x 30 mm; cylindrical, tapering slightly at both ends. Colour, in alcohol, an admixture of browns, paler ventrally; dorsum with eight pairs of dark blotches, whitish areas around bases of podia. Mouth terminal, tentacles 18, short, with light brown disc, 2 mm in diameter. Collar not evident. Anal papillae unequal, in five groups. Podia as scattered tubefeet, shorter dorsally, papilliform posteriorly. Calcareous ring ( Figure 18N ) high, radial plates longer than wide, with deep anterior ampullary notch and posterior slightly prolonged beyond level of interradial plates to form rudimentary bifurcations; interradial plates half the length of radial plates but just as broad with anterior, median tooth-like projection and deeply concave posterior margin. Polian vesicle single, short, midventral. Stone canal short, free, situated slightly to left of mesentery; madreporite well calcified, pyriform ( Figure 18M ). Right respiratory tree longer but left more profusely branched, both uniting before opening into cloaca. Gonad as single tuft of branched tubules on left of mesentery. Cuvierian tubules 15, short, thick, curved, attached to base of left respiratory tree.

Spicules of body wall tables and buttons. Tables few, of three types: commonest type ( Figure 18A–C ) with circular to subcircular, slightly spinose to smooth disc (40–75µm, mean 50 µm) with about eight marginal holes and a low spire (20–50 µm), terminating in a ring of about six blunt teeth, disc and spire frequently reduced ( Figure 18D ) but rarely rim knobbed or tables modified into fenestrated spheres ( Figure 18E ); second type like that of Mesothuria ( Figure 18 F,G ) with a smooth, slightly lobed disc (ca. 60 µm), perforated by 3– 4 central holes and 6–7 large marginal holes; spire low, terminating in a compact, often tripartite, cluster of teeth; third type of tables ( Figure 18H ) rare, found only ventrally, disc large, oblong, up to 100 µm, with uneven margins and perforated by four small central holes, a series of slightly larger holes outside these and usually another incomplete series on outside. Buttons ( Figure 18 I, J ) numerous, slightly knobbed, 30–60 µm, oval with usually a distinct shaft and smooth, slightly undulating, knobbed margins, holes 3(-7) pairs, often occluded, especially ventrally, where only a pair of holes may be present; rarely buttons smooth or modified into fenestrated ellipsoids. Podia with end-plates and elongate rods (up to 150 µm) with central and/or terminal perforations ( Figure 18L, K ). Tentacles, longitudinal and cloacal muscles without deposits.

Distribution Known only from type locality.

Remarks

This specimen was initially identified and described by the writer (see Thandar 1984) as H. (T.) notabilis Ludwig but due to inaccurate cutting and pasting it appears in the thesis as H. (T.) maculosa Pearson (see Remarks under H. maculosa above). Dr Rowe (pers. comm.), who examined the original description and slides, thought that the specimen perhaps represents a new species, close to H. (T.) maculosa , and this was recently verified by both Massin & Samyn (pers. comm.), who examined my holotype. Since then, I have had the opportunity to examine H. (T.) notabilis in the Natural History Museum (London) and conclude that the current specimen differs from it in possessing a different type of calcareous ring, three types of body wall tables, less spinose table discs and in the occasional presence of fenestrated spheres. In H. (T.) notabilis the radial plates of the calcareous ring are prolonged far beyond the posterior margin of the interradial plates and the anterior projections of the radial plates are rounded. Further, the tables of Ludwig’s species are mostly reduced, the discs very spinose, and fenestrated spheres absent. The new species can also be referred to the subgenus Cystipus but, due to its similarities with both H. maculosa and H. notabilis , it is here classified in Theelothuria . In any case both Theelothuria and Cystipus are closely related (see Rowe 1969:125).

Figures

FIGURE 18. Holothuria (Theelothuria) pseudonotabilis sp. nov. Holotype. SAM–A27943. A. Table from dorsal body wall (from side); B. tables from dorsal body wall; C. table from ventral body wall (from side); D. reduced ventral tables; E. fenestrated sphere from ventral body wall; table from ventral body wall (Mesothuria type); G. same (from side); H. table with multilocular disc; I. buttons from dorsal body wall; J. buttons from ventral body wall; K. rods from.dorsal podia; L. rod from ventral podium; M. madreporite; N. part of calcareous ring. (A & G scale a; H & I scale b)