Paracaudina tripoda O’Loughlin and Barmos, 2011

O'Loughlin, P. Mark, Barmos, Shari & VandenSpiegel, Didier, 2011, The paracaudinid sea cucumbers of Australia and New Zealand (Echinodermata: Holothuroidea: Molpadida: Caudinidae), Memoirs of Museum Victoria 68, pp. 37-65 : 61

Paracaudina tripoda O’Loughlin and Barmos sp. nov.

Figures 18 , 19

Material examined. Holotype. Queensland, east of Lady Elliot Island , 24º07'S 152º52'E, 230 m, 7 Jul 1984, AM J24922 .

Paratypes. Type locality and date, AM J18814 (3) ; east of Lady Elliot Island , 24º04'S 152º48'E, 192 m, 7 Jul 1984, AM J18813 (1) ; north of Fraser Island , 24º23'S 153º17'30''E, 137 m, 15 Dec 1977, AM J11150 (7).

Diagnosis. Paracaudina species up to 75 mm total length, diameter up to 27 mm; oral and caudal tapers, lacking long thin tail, sometimes short discrete tail; body wall firm, leathery, slightly rugose; small preserved specimens reddish-yellow (rusty), larger specimens off-white; reddish-yellow pigment may be present; mid-body with abundant irregularly round to oval, thick button-like ossicles, some slightly concave, up to 64 µm long; majority of ossicles with rounded edge, short thick surface spines, ossicles frequently with large central perforation with tripod or single rod or cross bridge, up to 11 variably sized perforations; many australis -like plates with horizontal marginal projections; some chilensis -like plates with bridging box and cross over central perforation, some with bridging tripod; rare ambigua -like mid-body plate ossicles with 2–4 perforations, up to 32 µm long.

Type locality. Northeast Australia, Queensland, E of Lady Elliot Island, 230 m.

Distribution. Northeast Australia, off Lady Elliot and Fraser Islands; 137– 230 m.

Etymology. From the Greek trion (three) and podos (foot), referring to the frequency of a tripod bridge over the central perforation in the ossicles.

Remarks. The holotype specimen of Paracaudina tripoda O’Loughlin and Barmos sp. nov. is damaged, but the ossicles are in good condition and the body form is evident. Three Paracaudina Heding, 1932 species lack a long thin tail and have irregular small plate or button ossicles in the mid-body wall. In two of these species, Paracaudina australis ( Semper, 1868) and Paracuadina cuprea O’Loughlin and Barmos sp. nov., the predominant ossicles from the mid-body are plates with lateral rounded marginal spines and surface spines and knobs. In the new species Paracaudina tripoda O’Loughlin and Barmos the predominant ossicles lack lateral rounded marginal spines, and have surface spines. Paracaudina australis specimens show rare slight yellowing, and have rods in the mid-body wall. Paracaudina cuprea specimens show strong reddish-yellow colouration with increasing size. Paracaudina tripoda specimens show decreasing reddish-yellow colouration with increasing size.

Figures

Figure 18. Photos of Paracaudina tripoda O’Loughlin and Barmos, sp. nov. (photos by L. Altoff, MRG). a, holotype from Queensland, east of Lady Elliot Island, 230 m (AM J24922); b, small paratype, north of Fraser Island, 137 m, (AM J11150 (7)).

Figure 19. SEM images of ossicles from the mid-body wall of the holotype of Paracaudina tripoda O’Loughlin and Barmos sp. nov. (AM J24922).