Triasemperia stola O’Loughlin, 2014

P. Mark O’Loughlin, Melanie Mackenzie & Didier Vandenspiegel, 2014, New dendrochirotid sea cucumbers from northern Australia (Echinodermata: Holothuroidea: Dendrochirotida), Memoirs of Museum Victoria 72, pp. 5-23 : 16-17

Triasemperia stola O’Loughlin sp. nov.

Zoobank LSID. http://zoobank.org:act:B8F02EEE-7711-4519BC96-DE02BD4433F3

Figures 9 , 10 .

Material examined. Holotype. N Australia, Joseph Bonaparte Gulf, 12.32°S 129.94°E, shell and sand substrate, RV Solander, 46 m, AIMS & GA, 5 Aug 2010, NMV F174889 (GA specimen 29084, SOL 5117, 013BS010; UF tissue lot MOLAF1541 ) .

Paratypes. NE Australia, Queensland, Yeppoon, dredged off Middle Island , 23.13°S 150.74°E, 9–37m, B. J. Smith, 6 Sept 1967, NMV F204083 (1) ; same data, NMV F204088 (1).

Description. Form cylindrical, elongate, upturned oral and anal ends, tapered orally, long taper anally, U-shape up to 45 mm wide (preserved); hard, thick, calcareous body wall, ‘prickly’ to touch; mouth anterior, anus posterior, lacking anal teeth; tube feet scattered over body, withdrawn, inconspicuous (preserved), diameters about 0.2 mm, paired radial series of tube feet on withdrawn introvert; 20 dendritic tentacles, 15 large, 5 inner small; calcareous ring composite, comprising small calcareous pieces, radial and inter-radial composite plates adjoin to create tubular ring, radial plates elongate with thin posterior distal prolongations adjoining inter-radial plate elongations, radial plates with median division for most of the length, inter-radial plates with deep posterior notch; single polian vesicle; gonad tubules with numerous branches; respiratory trees extending throughout the coelom.

Ossicles throughout body wall densely crowded thick tables, table discs triangular, typically with 6 large marginal knobs and 6 small perforations, discs 80–120 µ m wide, spires with 3 pillars and 6 pointed spines distally, disc width and spire height sub-equal. Introvert and tube feet with tables, rods, endplates; tables smaller, irregular, some lacking spires, perforations up to 19, discs up to 56–104 µ m wide; smooth rods with distal ends enlarged and perforated, up to 120 µ m long; endplates with diameters about 136 µ m, tube foot support ossicles tables only. Tentacles with rods, rosettes, tables; fine to thick smooth rods with swollen perforated ends; tables rare, form regular or irregular, some not knobbed, discs up 96 µ m wide.

Live colour red-brown to brown, preserved colour brown to off-white with residual violet colouration.

Distribution. Northern Australia, from Joseph Bonaparte Gulf to Yeppoon Queensland, 9– 53 m.

Etymology. Named stola with reference to the genus Stolus that has species with heavily knobbed button-like ossicles that are similar to the table discs of this species.

Remarks. The distinguishing morphological character of Triasemperia stola is the presence of table spires with three pillars. The calcareous ring and ossicles are similar to those of Stolus crassus Liao and Pawson, 2001 , but S. crassus from the South China Sea is described as having 10 tentacles and only 2 pillars in the table spires.

Family Thyonidiidae Heding and Panning, 1954 (sensu Smirnov 2012)

Remarks. Heding and Panning (1954) initially described the Thyonidiinae as a sub-family within the Phyllophoridae Östergren, 1907 . Based on the absence of posterior segmented prolongations on the calcareous ring Pawson and Fell (1965) transferred the Thyonidiinae to a sub-family within the Cucumariidae Ludwig, 1894 . Based on the presence of more than 10 tentacles and table ossicles Smirnov (2012) raised Thyonidiinae to family status as Thyonidiidae . The plate ossicles in Parathyonidium Heding (in Heding and Panning), 1954 and “reduced” ossicles in Athyonidium Deichmann, 1941 and Patallus Selenka, 1868 suggested to Smirnov (2012) that these genera were probably unrelated to the genera with tables.

Figures

Figure 9. Photos of live and preserved specimens of Triasemperia stola O’Loughlin sp. nov. A, lateral view of live holotype specimen (mouth right; NMV F174889); B, lateral view of preserved holotype (mouth right, lateral view width 45 mm); C, lateral view of preserved paratype (mouth right, lateral view width 50 mm, NMV F204088); D, photo of the calcareous ring of the holotype; insert with sketch of the calcareous ring.

Figure 10. SEM images of ossicles from the holotype of Triasemperia stola O’Loughin sp. nov. (NMV F174889). A, mid-dorsal body wall tables, spires with 3 pillars (scale bars 20 µm); B, peri-anal body wall tables (scale bars 20 µm); C, tube foot tables (scale bars 20 µm); D, tentacle rods (scale bars 20 µm).