New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach

Abstract

Deep-sea ophiuroids were collected by the manned submersible ‘Shenhaiyongshi’ from the South China Sea at depths of 500–3550 m, in 2017 to 2020. A total of 18 species were identified, including three new species and eight new records, increasing the total number of species known from the South China Sea to 304. Most of the ophiuroids recorded from the South China Sea were found in shallow waters (77.9%) and a few of them occurred only in deep water (20.4%). Three new species are described as Ophiacantha aster sp. nov., Ophiomoeris petalis sp. nov. and Ophiopristis shenhaiyongshii sp. nov. We provide comprehensive descriptions of morphological features, including characteristics of the arm skeletons, and a phylogenetic analysis based on COI and 16S sequences. Overall intraspecific and interspecific genetic distance variations among the families found in this study were 0.5% to 2.47% and 1.16% to 44.16%, respectively, along the South Pacific region to the South China Sea. Our phylogenetic analysis suggested that COI partial genes resolved the interspecies complexity in the class Ophiuroidea better than 16S partial genes. The order Euryalida had low interspecies genetic distance variation within the class Ophiuroidea. The present study suggests a high probability that species of Asteroschema and Gorgonocephalus are more widely spread around the Indo-Pacific region than previously expected.

First records of the Pacific sleeper shark Somniosus cf. pacificus in the western tropical Pacific

“…Data of larger mobile vertebrates, such as deep-sea shark species, are commonly limited to opportunistic observations, especially via strandings or incidents of by-catch. With an increase in deep-sea exploration efforts, as well as the development of cheaper technology that can go to greater depths for longer periods, data on species distributions have increased, which have resulted in many new species observations and range extensions (Buglass et al, 2020;Cerutti-Pereyra et al, 2018;Nethupul et al, 2022;Penney et al, 2020). These new insights can play an important role in species conservation and management.…”