Diversity of marine planktonic ostracods in South China Sea: a DNA taxonomy approach

Abstract

Ostracods (Crustacea, Ostracoda) are small bivalved crustaceans, contributing over 200 described species to the marine zooplankton community. They are widely distributed and are relatively abundant components of the mesozooplankton, playing an important role in the transport of organic matter to deep layers. However, identification of ostracods based on micro-morphological characters is extremely difficult and time-consuming. Previous fragmentary taxonomic studies of ostracods in the South China Sea (SCA), were based solely on morphology. Here, by analysing the mitochondrial COI gene, we explore the taxa across the SCA using molecular tools for the first time. Our results show that sequence divergence among species varies within a large range, from 12.93% to 35.82%. Sixteen of the taxonomic units recovered by DNA taxonomy agree well with morphology, but Paraconchoecia oblonga, Conchoecia magna and Halocypris brevirostris split into two clades each, each of which contains cryptic species.

Keywords:

• DNA taxonomy
• COI
• South China Sea
• ostracods

Acknowledgements

We thank Prof. Henri Dumont for providing useful comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are grateful for support from Central Public-interest Scientific Institution Basal Research Fund, South China Sea Fisheries Research Institute, CAFS [2017YB26], Chinese NSF Grants [41406188], Science and Technology Program of Guangdong Province, China [2014A020217011] and Chinese Agriculture Key Financial Fund [NFZX2013].