Perlophiura profundissima Belyaev & Litvinova 1972

Perlophiura profundissima Belyaev & Litvinova, 1972

Fig. 5H–I

Perlophiura profundissima Belyaev & Litvinova, 1972: 7–11, fig. 2, 3(1–3).— Litvinova 1975: 198.— Vadon & Guille 1984: 598–599, pl. 1(5).— Paterson 1985: 145, fig. 55.— Guille & Vadon 1986: 169.— Vadon 1991: 336–337.

Material examined. MD 50 DC34, MNHN IE.2009.1624 (1).

Distribution. NW Atlantic (3136–3162 m), NE Atlantic (4248–4462 m), NW Pacific (3380–8135 m), NE Pacific (3949–7200 m), W Atlantic (3500–5020 m), E Atlantic (3340–4412 m), W Indian (1575–5200 m), E Indo-W Pacific (1615–6890 m), E Pacific (2265–4370 m), S America (4209–4630 m), S Africa (2200–5280 m), S Australia (3389–5540 m), New Zealand (5400– 5400 m), Antarctic (4544–4545 m). SPA (2200 m).

Remarks. Genetic data provided by Christodoulou et al. (2019) show that Perlophiura belongs to the family Ophiosphalmidae, sister to the Ophiosphalma armigerum - O. glabrum - O. properum group. However, there was notable genetic divergence between Australian and Clarion-Clipperton Zone samples which indicates there could be more than one species within this genus. The extreme paedomorphic form of these animals (Stöhr & Martynov 2016) makes comparison difficult and Paterson (1985) has noted the variation in plating between specimens. The 2.8 mm dd MD 50 specimen has rectangular ventral disc scales on either side of the oral shield which were not figured in the type description. There are 2 arm spines, which are separated near the base of the arm with one short spine being situated ventrally on the distal side of the tentacle pore, but more spine like and lateral in position near the arm tips. It also appears to differ from all published figures of P. profundissima in having a small rectangular first VAP (without adjacent tentacle pores) between the second VAP (with pores) and the jaw slit. This is more in line with the morphology of Ophiosphalma and Ophiomusa (see Hendler 2018 fig. 3) where the tentacle pores associated with the first VAP are not visible from the surface, being hidden deep within the jaw slit. More specimens are required to resolve whether there are one or more species in this genus.