Podarkeopsis chinensis sp. nov. (Annelida, Hesionidae) from southeastern China

Podarkeopsis chinensis sp. nov. (Annelida, Hesionidae) is described based on specimens collected from the coast of southeast China. It is the first Podarkeopsis species described from the Indo-Pacific, although there are already nine valid Podarkeopsis species known from other parts of the world. This new species can be distinguished from the other Podarkeopsis species in having a palpostyle as long as the palpophore and double aciculae in both notopodia and neuropodia, and in bearing bifid furcate chaetae which have a smooth base on the shorter tine. A phylogenetic analysis based on the concatenated sequences of five gene fragments (COI, 16S rRNA, 18S rRNA, 28S rRNA, and histone H3) from 18 specimens of P. chinensis sp. nov. showed that they formed a monophyletic clade that is sister to P. levifuscina. K2P genetic distances indicated that the four gene fragments (COI, 16S rRNA, 18S rRNA, and 28S rRNA) of P. chinensis sp. nov. diverged from the corresponding sequences of the closest related species of Podarkeopsis in GenBank and BOLD Systems by 21.1-27.5%, 20.3-23.1%, 0.1-0.2%, and 2.1-3.2%. An identification key is provided for species in the genus Podarkeopsis.

Automated summary

Podarkeopsis chinensis sp. nov. is a newly described species of annelid found on the coast of southeast China. It is the first Podarkeopsis species discovered in the Indo-Pacific region and differs from other known species in various morphological features. Phylogenetic analysis based on genetic sequencing confirms its unique status and relationship to other species in the genus. The study also provides an identification key for Podarkeopsis species.