Prototrochus Beljaev and Mironov, 1982

O’Loughlin, P. Mark, 2007, New apodid species from southern Australia (Echinodermata: Holothuroidea: Apodida), Memoirs of Museum Victoria 64, pp. 53-70 : 66

Prototrochus Beljaev and Mironov, 1982

Figures 10, 11; Tables 1, 2

Diagnosis (after Gage and Billett, 1986). Myriotrochid with 10 tentacles; calcareous ring symmetrical, with dorsal and ventral plates subequal in size; dorsolateral radial plates with single anterior projection; wheels with teeth distributed regularly, pointing towards centre of hub; rods absent from body wall, sometime occurring in and around tentacles.

Remarks. Beljaev and Mironov (1982) referred 12 species to their new genus Prototrochus . Only Prototrochus australis ( Beljaev and Mironov, 1981) occurs near eastern Australia, the holotype coming from south of Lord Howe I. in the northern Tasman Sea at 1500 m. Beljaev and Mironov (1981) noted that their new species Myriotrochus australis was the smallest known myriotrochid. The 7 specimens comprise 2 complete and 5 incomplete specimens, none longer than 2.8 mm. The holotype (Stn 1244; oral end part specimen; less than 2 mm long) diagnostic characters of the “larger wheels” given by Beljaev and Mironov (1981) are summarized in Table 1. These characters vary greatly across the specimens of Prototrochus australis analysed by Beljaev and Mironov (1981), as do the distribution (5 locations from east of New Zealand to northern Tasman Sea) and depth range (570–3013 m), suggesting to me the probability of more than 1 species. Beljaev and Mironov (1981) acknowledged that their new species might well comprise “two or more species or subspecies”. The 3 new species from eastern Australia described below are diagnosed against the “larger wheels” data and illustrations given for the holotype of P. australis (Stn 1244) . The 3 new species described below are the first myriotrochid records for Australian continental waters.