Actinopyga capillata, Rowe & Massin, 2006

Rowe, Francis W. E. & Massin, Claude, 2006, On a new species of Actinopyga Bronn, 1860 (Echinodermata, Holothuroidea) from the Indo-West Pacific, Zoosystema 28 (4), pp. 955-961 : 956-960

publication ID	https://doi.org/ 10.5281/zenodo.4525493
persistent identifier	https://treatment.plazi.org/id/764687ED-FFBE-5F17-FC99-FEE67D8FFA3F
treatment provided by	Felipe
scientific name	Actinopyga capillata
status	sp. nov.

Treatment

Actinopyga capillata n. sp.

( Figs 1-3 View FIG View FIG View FIG )

Labidodemas semperianum – Arakaki & Fagoonee 1996: 122, pl. XIII, 4 (non L. semperianum Selenka, 1867 ).

Bohadschia subrubra – Muller 1998: 33, pl. 4a-d, g, h, pl. 6, figs g-j (non B. subrubra ( Quoy & Gaimard, 1833)) .

Actinopyga sp. – Erhardt & Baensch 2000: 960.

Actinopyga sp. nov. – Rowe & Richmond 2004: 3299 View Cited Treatment , fig. 9 (as Bohadschia sp. 1 in the legend of fig. 9; sphalm. typogr.).

HOLOTYPE. — La Réunion. Trou d’eau, night dive, back reef, 1 m depth, VII.2003, coll. M. Rard ( MNHN EcHh 8078)

TYPE LOCALITY. — La Réunion.

PARATYPES. — Rodrigues Island. Grande Baie, reef crest, Royal Geographical Society, Royal Society Shoals of Capricorn Programme, western Indian Ocean 1998-2001 (Shoals contribution no. P043), 22.IX.2001 ( BMNH 2004.2834). — Same data, upper shore, under stone, 19.IX.2001 ( BMNH 2004.2835). — Same data, reef crest, 16.IX.2001 ( AM).

OTHER MATERIAL EXAMINED. — Holotype of Bohadschia mitsioensis Cherbonnier, 1988 ( MNHN EcHh 3545) .

DISTRIBUTION. — Mascarene Islands ( La Réunion, Rodrigues Island, Mauritius), Philippines.

ETYMOLOGY. — “ capillata ” (Latin capillata = hairy) refers to the very long (1 cm) and thin, hair-like, dorsal tube feet of the species.

DESCRIPTION

Medium size holothuroid, holotype 90 × 35 mm, paratypes 67 × 24 to 120 × 24 mm.Body cylindrical, tapering posteriorly. Mouth ventral, surrounded by 16-20 greyish peltate tentacles; anus terminal with five small anal “teeth” (not observed in the two smallest paratypes); anal “teeth” yellowish, bearing knobs and blunt spines at the tip. Tube feet numerous dorsally and ventrally; ventrally feet stout, well developed in three broad bands along the ventral radius, dorsally scattered irregularly, very thin, long (up to 1 cm), hair-like.

Colour pattern of the type specimens: holotype ( Fig. 1A, B View FIG ) from La Réunion (90 mm long) dorsally with white/beige background, with one, well marked brown/orange transverse band at posterior end, and with at least two transversal bands at anterior end, ventral surface beige. Orange transverse bands prominent on a specimen photographed at La Réunion ( Fig. 1C View FIG ). The largest paratype from Rodrigues (120 mm long, preserved) dorsally beige/white background with at least 4, irregular, light-dark brown transverse patches, dorsal tube-feet/papillae brown (see Rowe & Richmond 2004: fig. 9), ventral colour not recorded.

Other specimens: Muller (1998) described specimens from Mauritius as being 15-20 cm long (in life) and as having “irregular pink-brown patches on a white background, papillae darkened at ends (i.e. tips), ventral side paler than dorsal side”.

Erhardt & Baensch (2000: 960) recorded the Philippine specimen in their photograph as being 25 cm long, with colour showing dorsal surface predominantly brown with 1 or 2 darker, transverse bands, shading lighter to white at posterior end and around anus; small spots and patches of white occur along dorsal-lateral edge and sparsely across dorsal surface; dorsal tube-feet/papillae black.

Body wall smooth to the touch, 3.5-4.5 mm thick in contracted specimens, 1 mm thick in relaxed specimen.

Calcareous ring similar to that of other species of Actinopyga with radial plates twice as wide as interradial plates ( Fig. 2A View FIG ). Stone canal single, very short, ending in ovoid madreporic plate located close to calcareous ring ( Fig. 2A View FIG ).Tentacle ampullae 1/10 of body length. Longitudinal muscles double, prominent. Few branched Cuvierian tubules, of actinopygid type with irregular, knobbed surface. Gonad of fine branched tubules (1 or 2 branches/ tubule). Polian vesicle not observed.

Few ossicles in body wall. Ossicles delicate, often (particularly in paratype specimens) broken in microslide preparations. Body wall ossicles, dorsally and ventrally,with smooth rosettes with rounded terminal swellings. At anterior end, dorsal body wall rosettes are 12-30µm long ( Fig. 2B View FIG ); at posterior end they are somewhat smaller (14-25 µm long) and more compact ( Fig. 2C View FIG ); ventral body wall rosettes, similar at anterior and posterior ends, 14-35 µm long ( Fig.2D View FIG ). Ventral tube feet with rods, 20-70 µm long ( Fig.2E View FIG ) and an end plate, 320-730 µm across, made of several pieces. Dorsal tube feet with long rods, 60-100 µm long, straight or slightly curved with spiny extremities ( Fig.3A View FIG ) and with small rods, 28-50 µm long, derived from rosettes ( Fig. 3B View FIG ); end plate of dorsal tube feet in one piece, 170-350 µm in diameter. Longitudinal muscles and retractor muscles of cloaca with small smooth, straight rods, 12-25 µm long ( Fig. 3C View FIG ) and 17-50 µm long ( Fig. 3D View FIG ), respectively. Cloacal wall with small, smooth, straight rods, 23-50 µm long and large forked, spiny rods, 75-110 µm long ( Fig. 3E, F View FIG ). In holotype, small smooth rods are much more numerous than forked spiny ones; it is the reverse in

paratype BMNH 2004.2834.Tentacles with straight or curved rods, spiny at extremities, 40-120 µm long ( Fig. 3G, H View FIG ).

REMARKS

Although the body wall ossicles of Actinopyga capillata n. sp. appear most similar to those of A. lecanora Jaeger, 1833 and A. agassizi (Selenka, 1867) (e.g., see illustrations of Panning 1944: figs 15, 16, 20; Cherbonnier 1988: fig. 4; Hendler et al. 1995: fig. 180G-I; Massin 1996: fig. 4), as Rowe & Richmond (2004: 3299) note, the shape of the body, together with the distinctive arrangement of the elongate, modified dorsal tube feet, and the ossicle complement, all set this species apart from others in the genus Actinopyga . The live colour pattern is also distinctive for A. capillata n. sp., within the genus

Interestingly, the ossicles of A. capillata n. sp. are also very similar to those described and illustrated for Bohadschia mitsioensis Cherbonnier, 1988 from Mitsio Island, west coast of Madagascar. However, following examination of the holotype of B. mitsioensis it is clear that the two species cannot be considered to be congeneric for the following reasons: 1) the occurrence of “anal teeth” (these may be reduced in size or non-distinguishable in smaller specimens of A. capillata n. sp.) which are always absent in Bohadschia ; 2) the presence of few, typically actinopygid, Cuvieran tubules (see Vandenspiegel & Jangoux 1992, 1993); 3) absence of Bohadschia -type grains in the ventral body wall (see Cherbonnier 1988: fig. 12A, B for B. mitsioensis ); and 4) presence of ossicles in the muscles (not present in B. mitsioensis or other Bohadschia species; see Samyn & Massin 2003: 2514; Samyn et al. 2005: 112).

Of ecological interest is the fact that the holotype of A. capillata n. sp. was photographed and collected on La Réunion Island during a night dive. Muller (1998: 33, 70) who records the species (as Bohadschia subrubra ) from “Trou d’eau douce lagoon”, Mauritius, comments that it is a nocturnal species which can be present in high numbers (a night-time transect survey recorded 43 individuals). Apparently it was seen on a variety of substrates feeding on fine sediment occurring on macroalgae and dead coral (Muller 1988: 70).