Holothuria (Vaneyothuria) serishae Thandar, 2025, sp. nov.

Holothuria (Vaneyothuria) serishae sp. nov. Figure 1 Holothuria (Vaneyothuria) integra Thandar, 2007: 46, text-figs. 21 & 22; Thandar, 2022: 238, fig. 126. Diagnosis. A medium-sized to large species of Holothuria (Vaneyothuria), up to 230 mm along dorsal surface; preserved colouration an add-mixture of grey and browns or white with dark patches anteriorly, paler ventrally, dark rings around dorsal podia. Podia generally scattered, minute, more abundant in the ventro-lateral radii than elsewhere; dorsal podia papilliform, borne on whitish wart-like prominences. Mouth ventral, ‘collar’ absent. Anus terminal, encircled by radial clusters of podia similar to those of body wall. Anal teeth absent. Tentacles 18–20, greyish-green to greyish-brown. Body wall leathery, slightly rough to the touch, only 2 mm thick. Calcareous ring sculptured, small in relation to body size. Water-vascular ring situated far behind the calcareous ring (12 mm in holotype, 25 mm in paratype 3). Polian vesicles numerous, of various sizes (largest about 8 mm long) but of regular form, sometimes very tiny and positioned all around the water ring; stone canals also multiplied, situated in clusters around the water ring or attached directly to water ring without a canal (at least in paratype 2), sometimes a single madreporite supplied by three stone canals. Cuvierian tubules absent. Body wall tables with spinose disc (55–74 µm), perforated by four large central holes and a varying number of peripheral ones in a single series, disc often reduced; spire low to moderate (36–48 µm), of four pillars terminating in a perforated crown bearing numerous teeth (about 12), often arranged as a ‘Maltese’ cross at the distal end of spire. Buttons (45–71 µm) usually smooth, oval, quite regular, with 3–7 pairs of holes. Dorsal and ventral podial deposits as rods (148–152 µm), expanded and perforated in the middle and at ends, plus narrow, elongate plates (68–161 µm), with irregular margins and 2–3 series of holes. Tentacles with curved, spinulated rods (19–526 µm). No ossicles detected in longitudinal muscles. Etymology. The new species is named after my intern, Serisha Gangaram, in appreciation of her tireless assistance during the preparation of my intensive taxonomic monograph of the southern African sea cucumbers (see Thandar 2022). Material examined. The larger of the two specimens described in 2007 is chosen as the holotype. and the other is here designated Paratype 2. A third specimen, later received from the SAM, judging from the data on the label, is part of the same collection and here briefly described as Paratype 1. Holotype: SAM-A27945, off Inhambane, Mozambique, 23° 08’ S, 35° 42’ E, R. V. ‘ Algoa’, Mozambique, SCAD survey St. C 00815-014-012- 2144, 12.vi. 1994, 180 m. Paratype 1: SAM-A27945, same data as holotype Paratype 2: SAM-A27946, south of Inhambane, 24° 52’ S, 35° 20’ E, R. V. ‘ Algoa’, Mozambique SCAD Survey St. C, 00809-014-007- 2164, 11.vi. 1994, 164 m. Descriptions of Paratypes. Paratype 1: SAM-A27945: Length about 200 mm; width of mid-body about 40 mm. Specimen to large extent macerated, perhaps due to previous dissection or evisceration - gut, gonad and one respiratory tree lying free in preservative. Colour, in preservative, uniformly whitish grey, slightly darker anteriorly, but with no distinct markings, blotches or bands. Dorsal tube feet papillose, borne on minute knobs/tubercles. Ventral surface smooth, almost naked, mostly without podia - apparently an abnormality or due to poor relaxation before preservation. Calcareous ring in normal position, water ring not particularly situated far behind calcareous ring. Multiplicity of Polian vesicles discernable but clarity obscure. Stone canals not observed. Cuvierian tubules absent. Paratype 2: SAM-A27946: Length 165 mm, width in mid-body 30 mm, dark yellowish-brown dorsally, paler ventrally, papillae on wart-like prominences; tentacles 20, greyish-green to greyish-brown in colour; calcareous ring not particularly sculptured, water ring situated 25 mm behind calcareous ring, Polian vesicles mostly sacciform, situated all round ring; stone canals 17, six on left and 11 on right; with at least three madreporic bodies on right side arising directly from water ring and another terminating in two madreporic bodies, a single madreporic body on right side served by three stone canals; tables with mostly smooth disc and a more pronounced ‘Maltese’ cross; podial rods more perforated at the extremities than those of the holotype. Specimen preserved with pearlfish contained in a separate vial. Type locality. Off Inhambane, Mozambique, 23° 08’ S, 35° 42’ E. Distribution. Southern Mozambique, continental slope, 164– 180 m. Remarks. Holothuria (Vaneyothuria) integra is well described by Koehler & Vaney (1908) and more recently by Cherbonnier & Féral (1981), and its synonym H. neozelanica by Mortensen (1925). All these descriptions record the presence of Cuvierian tubules, a single Polian vesicle and multiple stone canals. The southern African specimens, which hardly differ from Holothuria integra in both external features and ossicles, have in contrast, not only multiple stone canals but also multiple Polian vesicles, no Cuvierian tubules, and a distantly displaced water ring. These features in combination warrant the description of a new species. It may be argued that the distantly removed southern African population perhaps deserve a subspecies status but, judging from the number of morphological variations, especially the absence of Cuvierian tubules and multiplicity of Polian vesicles, a new species is here justified. A similar case exists in the tropical Indo-Pacific sympatrics H. (Halodeima) atra Jaeger, 1833 and H. (H.) pulla Selenka, 1867, separated by the presence of Cuvierian tubules in the latter and their absence in the former. It is here noted with interest that Cherbonnier & Feral (1981) also described a distantly displaced water ring, 30 mm behind the calcareous ring. The new species also comes quite close to H. (V.) uncia Rowe, 1989, which is described as having tube feet in three bands ventrally and scattered dorsally; table discs as smooth, squarish to roundish, spire with one or two cross-bars and some buttons bearing knobs. It’s a pity Rowe (1989) does not mention the number of Polian vesicles and stone canals nor the absence or presence of Cuvierian tubules. But judging from the form of the table disc and spire it appears to be a distinct species. From amongst its consubgenerics, the new species comes quite close to the north-east Atlantic H. (V.) suspecta Cherbonnier, 1958, which also has multiple stone canals but a very distinctly spinose rim to the tables, heavily dentate crowns and tentacle deposits often perforated by a few terminal holes. H. (V.) sinefibula Cherbonnier, 1963, also from the north-east Atlantic, is poorly described and not illustrated. It also appears to come quite close to the new species but Rowe (1969) is of the opinion that it may be a juvenile of H. suspecta. The distinctive features of the new species are the absence of Cuvierian tubules, the presence of multiple Polian vesicles, the fact that the water ring is situated far behind the level of the calcareous ring and distinctly serrate tables with a 12-toothed crown.