Application of barcoding and geometric morphometrics on resolving Physocypria Vávra species complexes

Abstract

This research employs integrative taxonomy approach to distinguish between closely related and cryptic species. I use geometric morphometrics analyses of the shell and soft body and the common barcoding gene (mitochondrial cytochrome oxidase subunit I) as methods to resolve potential species complexes in the freshwater ostracod genus Physocypria Vávra, 1897. My research combines some already published molecular data on P. biwaensis (Okubo, 1990) and P. nipponica Okubo, 1990 from Lake Biwa, and newly acquired ones for P. kraepelini Müller, 1903 and several populations of Physocypria spp. collected from Korea. The Korean populations were provisionally identified as P. nipponica and P. kraepelini. The results of my molecular analyses and geometric morphometrics confirm that P. biwaensis is actually a complex of two species, while I confirm the presences of P. nipponica and dispute the presence of P. kraepelini from Korea. In fact, I recognize two new Korean Physocypria species. My results show that of all studied morphological characters shell and sexual characters are most reliable in distinguishing between closely related and/or cryptic ostracod species.