Holothuria (Theelothuria) duoturriforma, 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 : 37-39

Holothuria (Theelothuria) duoturriforma sp. nov.

Figure 17

Diagnosis

Perhaps a small species, type 40 mm. Colour, in alcohol, white with scattered dark blotches. Podia minute, papilliform, scattered. Papillose collar evident. Anus encircled by five clusters of papillae. Tentacles?20, whitish. Cuvierian tubules absent. Spicules of body wall tables and buttons. Tables of two sizes: either with a large disc (42–81 µm) of the Mesothuria type and a tall spire (42–68 µm) with 2–3 cross-bars or a small disc (39–65 µm) and a short spire (26–39 µm) with usually a single cross-bar, smaller type usually at bases of podia. Buttons restricted to bases of podia and anal region, elongated or oval (45–77 µm, mean 65 µm), with 3–4 pairs of holes and few knobs.

Etymology The specific name refers to the two types of tables found in the body wall.

Type SAM-A27942 .

Type locality Off Lala Nek , KZN, South Africa, 72 m.

Material examined Holotype only, NMDP, St. ZD 6, off Lala Nek (27° 13.0 ' S, 32° 49.7 ' E), 72 m, 7 vi 1990. Description

Specimen small, poorly preserved, eviscerated, most of gut and associated structures lost. Body form subcylindrical, dorsal surface arched, ventral flattened but not much so. Anterior end slightly broader than posterior end. Length 40 mm, width in mid-body 9 mm. Colour, in alcohol, white with dark scattered blotches. Mouth anterior, sub-ventral; anus terminal. Podia minute, papilliform, slightly longer ventrally, scattered but with some indication of arrangement in bands. Papillose collar evident. Anus encircled by five clusters of 3– 4 papillae per cluster. Tentacles?18, small, white to slightly beige in colour. Body wall 1 mm thick, gelatinous, smooth.

Calcareous ring damaged; radial plates squarish, as long as wide, with an anterior notch and some evidence of posterior bifurcations; interradial plates small, triangular, projecting slightly beyond anterior border of radial plates. Tentacle ampullae short; Polian vesicle single, sac-like; stone canal short, free, slightly twisted, terminating in an oval, globular, well-calcified madreporite ( Figure 17L ). Gonad and alimentary canal lost. Right respiratory tree shorter, reaching only half body length, both trees well branched, united at base. Cuvierian tubules absent.

Spicules of body wall comprise tables and buttons. Tables of two sizes: either with a large disc (42–81 µm, mean 59 µm) and a tall spire (42–68 µm, mean 53 µm) ( Figure 17C–E ), or a small disc (39–65 µm, mean 54 µm) and a short spire (26–39 µm, mean 32 µm) ( Figure 17 F ), smaller type common at bases of podia. Larger tables of Mesothuria type, disc with mostly undulating or occasionally spinose rim, pierced by usually eight large, oval holes, and sometimes with one or more smaller holes outside the larger ones, spire with 2–3 crossbars, terminating in a ring of several teeth. Smaller table discs somewhat circular, also with about eight marginal holes but a short spire with usually a single cross-bar, margin of disc sometimes turned up giving a cup and saucer appearance to table in lateral view; occasionally tables reduced to button-like discs. Buttons ( Figure 17A ) rare, restricted to bases of podia and anal region, elongate or oval (45–77 µm, mean 65 µm), usually with 3–5 pairs of holes and several knobs, the latter either restricted to the central shaft or to margins or both; buttons sometimes reduced to just two pairs of central holes. Podial deposits comprise small tables, buttons, perforated rods often developed as smooth plates, and end-plates. Podial tables ( Figure 17G ) similar to the smaller type from body wall; podial buttons (45–78 µm mean 65 µm), usually heavily knobbed ( Figure 17B ), with 2–5 pairs of holes; rods (71–113 µm, mean 91 µm), straight or slightly curved ( Figure 17I ), with 1–2 holes at ends and/or in the middle; plates with usually irregular margins and 5–10 pairs of holes ( Figure 17H ); end-plates of two sizes, small ones about 148 µm, large ones ( Figure 17J ) about 187 µm, both with large central holes and smaller peripheral ones but some peripheral holes often as large as central holes. Tentacle with slightly curved, non-perforated rods (39–142 µm, mean 71 µm), usually with slightly spinose margins ( Figure 17K ). Cloacal and longitudinal muscles without spicules.

Distribution Known only from type locality.

Habitat Slightly muddy sand, pennatulids.

Remarks

Of the 14 nominal and one indeterminate species currently classified in the subgenus Theelothuria , the present specimen comes close to H. (T.) squamifera Semper, 1868 from the Philippines and the Red Sea and H. (T.) asperita Cherbonnier & Féral, 1984 from New Caledonia. However, it is not identical to either of the two species. It differs from the former in the height of the table spires, fewer cross-bars to the spires, larger size of the holes on the discs and more nodular buttons, of especially the podia. It differs from H. (T.) asperita in the absence of smooth buttons, the larger size of the holes of the discs of the larger tables and the nature of the table crowns. There is also some resemblance of the new species to H. (Platyperona) insolita Cherbonnier, 1988 from Madagascar, especially in the type of tables, their two sizes, and the rarity of buttons. However, Cherbonnier illustrates only smooth buttons with a median optical discontinuity from the anal region of his specimen as well as some minute plates and pseudobuttons. Some reduced tables of the new species resemble those of H. (T.) klunzingeri Lampert, 1885 and H. (T.) notabilis Ludwig, 1875 but there are gross differences, most notably in the absence of tall-pillared tables in both H. (T.) klunzingeri and H. (T.) notabilis , suspected by Panning (1935) to be conspecific. It is noteworthy that there are no tack-like tables in the body wall and podia of the new species and although the larger tables are of the synallactid-type, they resemble those of the genus Mesothuria rather than those of Synallactes .

Figures

FIGURE 17. Holothuria (Theelothuria) duoturriforma sp. nov. Holotype. SAM–A27942. A. buttons from base of podium; B. knobbed podial buttons; C. large body wall tables from side; D. large body wall tables; E. large body wall table from beneath; F. small tables; G. small tables from side; H. podial plates; I. podial rods; J. ventral end-plate; K. tentacles rods; L. madreporite (different views). (A–K scale a; L scale b)