New record of the feather star Palaeocomatella hiwia (Echinodermata: Crinoidea: Comatulida) from Zhenbei Seamount in South China Sea: new insights into the taxonomic position of Palaeocomatella

One specimen belonging to the family Comatellinae was collected from the Zhenbei Seamount (332.5-478.2 m) in the South China Sea in July 2022. Based on the morphological characters, the specimen was identified as Palaeocomatella hiwia McKnight, 1977. It is first recorded from China Sea and redescribed in detail. This specimen differs from the original description from New Zealand for never showing syzygy at br(4+5) or br(5+6) on interior and br(1+2) on exterior arms. However, it is much conform to the redescription to specimens from Indonesia, with only differences in position of the second syzygy and distalmost pinnule comb. Specimen is deposited in the Institute of Oceanology, Chinese Academy of Sciences. Phylogenetic analyses based on the mitochondrial c oxidase subunit I (COI) and 16S rRNA genes indicated that P. hiwia was nested within the tribe Phanogeniini and clustered with Aphanocomaster pulcher. Furthermore, P. hiwia showed same morphological features in terms of mouth placement, comb location, and number of comb teeth rows as other genera of Phanogeniini. Therefore, we suggest that the genus Palaeocomatella should be put in the tribe Phanogeniini.

Automated summary

This study reports the collection of a specimen belonging to the family Comatellinae from the Zhenbei Seamount in the South China Sea, which is identified as Palaeocomatella hiwia. It is the first record of P. hiwia from the China Sea and a detailed redescription is provided. Phylogenetic analyses based on genetic data indicate that P. hiwia is closely related to Aphanocomaster pulcher within the tribe Phanogeniini. The morphological features of P. hiwia also support its placement within the Phanogeniini tribe.