Bathyplotes aymeric VandenSpiegel

Samyn, Yves & Vandenspiegel, Didier, 2016, Sublittoral and bathyal sea cucumbers (Echinodermata: Holothuroidea) from the Northern Mozambique Channel with description of six new species, Zootaxa 4196 (4), pp. 451-497 : 474-476

Bathyplotes aymeric VandenSpiegel sp. nov.

( Fig. 17 A – E)

Materiel examined. Type material: IE-2007-785 (holotype, collected in front of Mahajamba Bay); IE 2007-769 (1 paratype, collected between Majunga and Cape Saint-André) .

Type locality. Madagascar, between Majunga and Cape Saint-André, Station CP 3273 (Decimal coordinates: - 15.5; 46.06); in front of Mahajamba Bay , Station CP 3281 (Decimal coordinates: -14.97; 46.95)

Etymology. This species with elegant ossicles is named after Aymeric VandenSpiegel , son of Joelle Dellis and Didier VandenSpiegel, in recognition of his patience when his dad is ‘cleaning sea cucumber skeletons at home.

Known geographic description. For now only known from the type locality.

Taxonomic description (holotype and paratype). External anatomy — Holotype 12 mm long and 6 mm wide (fig. 17A). Paratype 19 mm long and 9 mm wide. Body with rounded extremities. Bivium somewhat rounded and trivium flattened in holotype, undeterminable in paratype. Body wall gritty to the touch. Bivium with some scattered papillae and laterally with a row of papillae. Trivium seemingly devoid of appendages. Anus terminal. Mouth ventral, tentacles could not be observed. Color in alcohol uniform brown.

Internal anatomy —calcareous ring with radial plate twice as long as wide, with anterior and posterior invagination; interradial pieces wider than radial ones, with anteriorly a long and fine tooth and with a straight posterior margin. Stone canal, Polian vesicle and gonad not observed. Respiratory trees very fine, nearly transparent, reaching nearly the anterior end. Longitudinal muscles very narrow, flat, undivided and marginally attached.

Ossicles —Dorsal and ventral body wall with similar numerous tables with a cross-shaped disc surmounted by a long spire (50 to 90 µm long) and a few tables with a more or less circular disc and a reduced spire (fig.17B). Cross-shaped disc 180 – 204 µm across, 2 to 5 racket-shaped arms perforated at their extremities; four, rarely 5 pillars united by up to 6 cross beam ending in a moderately spiny crown (fig. 17B,C). Dorsal papillae with perforated plates (120 to 180µm long), and tables similar to those of body wall. Lateral papillae with curved rods, plates and tables (fig. 17D); tables generally similar to the ones observed in the body wall but some with a higher spire (140µm high) and seven cross beam. Longitudinal muscles with spiny rods up to 237µm long (fig. 17E).

Remarks. The undivided longitudinal muscles and the predominantly four-pillared tables leave no doubt that this species belongs to the Bathyplotes . The long spires with numerous crossbeams resemble those in B. cinctus Koehler & Vaney, 1910 . However, the latter species always has tables with four arms whereas in H. aymeric there can be up to 5 arms. Moreover, B. cinctus presents C-shaped ossicles whereas H. aymeric does not. Lot IE 2007- 769 contained two specimens; one is however not a holothuroid.

Figures

FIGURE 17. Bathyplotes aymeric sp. nov. A: Dorsal view of holotype; B – E: SEM photos of ossicles from ventral body wall (B), dorsal body wall (C), lateral papillae (D) and longitudinal muscles (E). Scale bars: A = 1 cm; C – D = 20 µm; E = 50 µm.