Phyllostauros 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 : 285-288

Phyllostauros O’Loughlin gen. nov.

Diagnosis. Dendrochirote holothuroids with 20 tentacles, 5 large pairs alternating and 5 small pairs; body covered with tube feet; calcareous ring with 5 paired composite posterior tapering prolongations, arising jointly from the radial and inter-radial plates; body wall ossicles crosses with bifurcate ends, 1 or 2 surface spines near the ends.

Type species. Thyone vercoi Joshua and Creed, 1915 (monotypic).

Distribution. Central southern Australia.

Etymology. From the first part Phyllo of the relevant family name Phyllophoridae , with stauros (Greek for cross) referring to the body wall ossicle form.

Remarks. Thyone vercoi Joshua and Creed, 1915 was erected for one specimen that is now dry and in poor condition (holotype, SAM K1374). The authors made three permanent microscope slides from parts of the dorsal body wall, pharynx and a tentacle. These slides are in good condition, and held by SAM. H. L. Clark 1946 refers to additional slides held in MCZ. The tentacle crown is damaged, but there are more than the 10 tentacles reported originally, and close to 20. The calcareous ring is composite with posterior prolongations, but is not tubular as in southern Australian Thyone Oken, 1815 species.

Based on the cross ossicles in the body wall H. L. Clark 1946 referred Thyone vercoi to Staurothyone H. L. Clark, 1938 , but with reservations. He noted that Deichmann thought that the species was identical with Lipotrapeza vestiens ( Joshua, 1914) . Genus Staurothyone is in family Cucumariidae . Thyone vercoi has close to 20 tentacles, composite posterior extensions to the plates of the calcareous ring, and tube feet all over the body (close ventrally, scattered and sparse dorsally). Thyone vercoi belongs in family Phyllophoridae , not Cucumariidae , and cannot be retained in Staurothyone . Thyone vercoi is unique amongst Phyllophoridae species for the presence of body wall cross ossicles and absence of table ossicles. Rowe 1982, and Rowe in Rowe and Gates 1995, anticipated the need for a new genus. Phyllostauros O’Loughlin gen. nov. is erected here as a monotypic genus, and is referred to family Phyllophoridae and sub-family Phyllophorinae with reservations because of the unique cross ossicles in the body wall.