Phyrella? tenera ( Ludwig, 1875 ), 1954

Michonneau, François & Paulay, Gustav, 2014, Revision of the genus Phyrella (Holothuroidea: Dendrochirotida) with the description of a new species from Guam, Zootaxa 3760 (2), pp. 101-140 : 133

Phyrella? tenera ( Ludwig, 1875)

Orcula tenera Ludwig, 1875:95 , fig. 21. Holotype, Museum Godeffroy (no longer extant as an institution; type not located); type locality: Samoa, Upolu Island, 20 fathoms

Orcula tenera: Lampert, 1885: 167–168 ; Théel, 1886: 149; Ludwig, 1888: 812–813 (fig. 18–20 pertain to Indonesian specimen that may not pertain to species)

Semperiella tenera: Heding & Panning, 1954:180–181 , fig. 86

Remarks. Described from a small specimen (2.5 cm long, 6 mm wide) without gonads suggesting to Ludwig that it is a juvenile. The specimen was described as light yellow, with not very numerous tube feet scattered all over the body, and 10 large and 5 small tentacles. The ossicle assemblage is composed of very few tables and some rosettes. The calcareous ring (Ludwig fig. 21c) has fragmented radials and inter-radials, former extended in long posterior prolongations.

This species is only unambiguously known from the type and has not been studied since its original description, and its whereabouts is unknown. It was not found during recent searches of the ZMH (Zoologisches Museum zu Universität Hamburg), ZMB (Museum für Naturkunde, Berlin), ZMUC, MCZ. The description is insufficiently detailed and the specimen is a juvenile making species level identification and even generic assignment impossible. Therefore, we consider this to be species inquirenda. Based on the limited information on hand, this species fits best in Phyrella ; based on the number of tentacles, structure of calcareous ring, the presence of tables and rosettes. It was considered a likely synonym of Thyonidiella oceana by Cherbonnier (1988, see also Rowe & Richmond, 2004) a species we consider a synonym of Phyrella fragilis . The specimen was taken much deeper than any other species of Phyrella , and from further out in the Pacific.

This species has also been recorded in the literature from the Red Sea ( Lampert, 1885 and Heding & Panning, 1954 based on different specimens) and Java (Pulo Edam - Ludwig, 1888 and Bay of Batavia - Sluiter, 1887 and Engel, 1933). Heding & Panning (1954) considered the two specimens from Bay of Batavia reported on by Sluiter and Engel to pertain to Phyrella fragilis , because they were described with 20 rather than 15 tentacles. However as noted above, tentacle number is not a reliable distinguishing feature of these species, and 15–17 tentacles are known from reliably identified and studied P. fragilis . The descriptions provided by all these papers are too limited to allow reliable species attribution without reexamining the specimens, although all could pertain to Phyrella .

Ecology & Distribution. Recorded with certainty only from the type locality, Samoa from fairly deep water (20 fathoms, ~ 37 m) relative to other Phyrella .