Revision of the Australasian species of the genus Mesocyclops Sars, 1914 [Copepoda: Cyclopidae]

Using new material and museum collections, a taxonomic and zoogeographical overview of the Australasian Mesocyclops is provided. The detailed morphological descriptions are supplemented with critical reassessment of the published records, a key to the Australasian and Oriental representatives of the genus (30 spp.) and distribution maps of the Australasian species and their extralimital relatives. The paper reports on the occurrence of sixteen species, 11 of them endemic, in Australasia: M. dayakorum sp. nov., M. darwini Dussart et Fernando 1988, M. pseudoannae Van de Velde, 1987, M. cf. yenae, M. yesoensis Ishida 1999, M. papuensis Van de Velde, 1987, M. aspericomis (Daday, 1906), M. ogunnus Onabamiro, 1957, M. affinis Van de Velde, 1987, M. tobae Kiefer, 1933, M. francisci sp. nov., M. woutersi Van de Velde, 1987, M. friendorum sp. nov., M microlasius Kiefer, 1981, M. geminus sp. nov., M. thermocyelopoides Harada, 1931. New synonymy: M. papuensis (M. borneoensis Dussart et Fernando, 1988). Closely related species pairs/groups seem to indicate some repeating pattern of relationships: 1. Palaeotropical; 2. Oriental; 3. Australasia/Africa disjunction; 4. Speciation within Australasia.