A new species of Schizopera (Copepoda: Harpacticoida) from Japan, its phylogeny based on the mtCOI gene and comments on the genus Schizoperopsis
Karanovic, T and Kim, K and Grygier, MJ, A new species of Schizopera (Copepoda: Harpacticoida) from Japan, its phylogeny based on the mtCOI gene and comments on the genus Schizoperopsis, Journal of Natural History, 49, (41-42) pp. 2493-2526. ISSN 0022-2933 (2015) [Refereed Article]
The predominantly marine genus Schizopera Sars, 1905 has only two significant inland water species-flocks, one in the ancient African Lake Tanganyika and the other in subterranean waters of Western Australia. Discovery of Schizopera abei sp. nov. from several interstitial locations in the vicinity of the ancient Lake Biwa has wider implications for the study of morphological homoplasies in the genus, as well as for the study of freshwater invasions in harpacticoid copepods. The new Schizopera species belongs to a small group of congeners with a two-segmented endopod of the fourth leg, which used to be recognised as a separate genus, Schizoperopsis Apostolov, 1982. Our reconstructed phylogenies based on the mtCOI partial sequences suggest that this character probably evolved convergently in at least some Schizopera, thus rendering the genus Schizoperopsis polyphyletic. However, almost all basal nodes in our cladograms are weakly supported, which shows limitations of a single-gene approach for reconstructing phylogenetic relationships. The new species is the first member of its genus from Japanese inland waters, and it has no close relatives among extent congeners anywhere in the world. We speculate that its ancestor may have invaded Lake Biwa, and subsequently its surrounding subterranean waters, from brackish areas around central Japan, presumably during a period of high sea water level through its major outflow river. This discovery may provide further support for the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats.
ancient lakes, barcoding, phylogeny, stygofauna, taxonomy