Thyone spenceri O’Loughlin, 2012

O’Loughlin, P. Mark, Barmos, Shari & VandenSpiegel, Didier, 2012, The phyllophorid sea cucumbers of southern Australia (Echinodermata: Holothuroidea: Dendrochirotida: Phyllophoridae), Memoirs of Museum Victoria 69, pp. 269-308 : 303-306

Thyone spenceri O’Loughlin sp. nov.

Figures 17e , 23

Material examined. Holotype. South Australia, Upper Spencer Gulf, Backy Point – West, 32º50'S 137º50.52'E, 18 m, SA Fisheries Department, Sep 1987, SAM K2562 (ring, tentacle crown, anterior part of body wall).

Paratype. Upper Spencer Gulf , Port Bonython, 33º01'S 137º45'E, 15 m, SA Fisheries Department, Sep 1987, SAM K2565 (1, ring, tentacle crown, anterior part of body wall) .

Diagnosis. Anterior body and calcareous ring 13 mm long (preserved), body wall soft; 10 tentacles, 8 large 2 ventral small; complete close cover of small tube feet; calcareous ring composite, tubular, posterior ends of composite plates not joined; radial plates tapered anterior with terminal split, long paired composite posterior prolongations separated for most of length, narrowing and further divided distally for about a quarter of total plate length, not joined; inter-radial plates composite, tapered to anterior point, truncate posteriorly; stone canal attached to alimentary canal mesentery, ‘split-pea’ madreporite form; single polian vesicle.

Anterior body wall with abundant tables, tables regular, discs round to oval to triangular, up to 96 µ m long, 2 large central perforations, smaller perforations nearer margin, predominantly 40–50 small perforations, spires with 2 pillars, 24 µ m long, 2 tapered ends distally; some table discs rosettelike; some table discs curved for tube foot support; tentacles with abundant perforated plates, rosettes; plates variable in shape, some plates narrow, elongate with large perforations and distal blunt teeth, sometimes small branches along margin of plate, plates up to 280 µ m long, some plates cross-shaped with perforate arms, some plates oval with four large central perforations, smaller surrounding ones and distal blunt teeth, plates up to 160 µ m long, some plates curved with denticulate margin and numerous small perforations, plates up to 120 µ m long; rosettes oval, up to 88 µ m long; peri-oral body wall with tables and rods; tables with 2 spires, discs with 2 central large perforations, small perforations between central large ones and disc margin, each disc with up to more than 30 small perforations, discs about 104 µ m long; peri-oral ossicles irregular wide perforated rods, up to 272 µ m long, sometimes crosses.

Colour (preserved). Body off-white; tentacles brown with dark brown to black markings.

Distribution. South Australia, Upper Spencer Gulf, 15– 18 m.

Etymology. Named with reference to Spencer Gulf in South Australia where the type specimens were collected.

Remarks. Both the holotype and paratype of Thyone spenceri O’Loughlin sp. nov. are damaged and most of the body wall has been lost. But there are good morphological systematic characters for the erection of this new Thyone Oken species. Thyone spenceri is distinguished from other southern Australian Thyone species in the key (above).

Figures

Figure 17. Photos of preserved specimens. a, holotype of Thyone flindersi O’Loughlin sp. nov. (NMV F151847) (insert: form of the calcareous ring plates); b, specimen of Thyone okeni Bell, 1884 (AM J10868); c, holotype of Thyone joshuai O’Loughlin sp. nov. (SAM K2566) (insert: form of the calcareous ring plates); d, holotype of Thyone kerkosa O’Loughlin sp. nov. (WAM Z31838); e, holotype of Thyone spenceri O’Loughlin sp. nov. (SAM K2562) (insert: form of the calcareous ring plates); f, holotype of Thyone tourvillei O’Loughlin sp. nov. (NMV F174902) (insert: form of the calcareous ring plates).

Figure 23. SEM images of ossicles from paratype of Thyone spenceri O’Loughlin sp. nov. (SAM K2565). Tables from anterior body wall (top); plates and rosettes from tentacles (bottom).