The Labidocera pectinata group: an Indo-West Pacific lineage of planktonic copepods with descriptions of two new species

The Labidocera pectinata species group is recognized as a unique monophyletic lineage within the primarily tropical Indo-West Pacific radiation of coastal water species encompassed by the Labidocera kroyeri complex. Both categories are defined and the six species comprising the pectinata group, including two new to science, are diagnosed. Review of available facts supports the proposal that L. bipinnata be ranked as a junior synonym of L. rotunda. Phylogenetic relationships within the group based on sexually modified characters are assessed. Two geminate pairs of parapatric species are identified. The geographic ranges of one pair are adjacent in the Andaman Sea, those of the other pair in the vicinity of Cape York, Australia. Each pair appears to be a consequence of a relatively recent speciation event. The apparent phylogenetic intermediacy of L. japonica linking the two tropical species of Asia and the three from Papua-Australia suggests an older sequence of trans-hemisphere spreading and diversification.