Psychropotes Théel, 1882

Genus: Psychropotes Théel, 1882 View in CoL

Diagnosis (following Hansen, 1975). Anus ventral. Unpaired dorsal appendage present. Circumoral papillae absent. Tentacle discs of a fixed shape, rounded in outline and with marginal knobs.

Remarks. Psychropotes is a deep-sea genus, typically dark purple or yellow, and known for its prominent sail or fin-like dorsal appendage. Of the 19 currently accepted species of Psychropotes worldwide, three have been previously recorded for Australia: Psychropotes depressa , P. longicauda and P. scotiae (WoRMS, ALA, and NMV catalogue January 2024). Two of these species are recorded again here: P. depressa and P. longicauda . Nine lots of Psychropotes were recorded from the IOT voyages at depths of 2289–5414 m, with seven lots further identified to OTU species level as follows: P. depressa (5 lots), P. longicauda (1 lot), and Psychropotes sp. MoV. 7327 (1 lot). Both COI and 16S sequence data highly support Psychropotes as a monophyletic genus. Within the COI phylogeny, P. depressa is basal to the clade containing P. longicauda , P.moskalevi , and P. verrucicaudatus . For 16S, only sequences for P. depressa and P.longicauda are available; each species forms a well-supported genetic lineage (fig. S1).