The sea skaters, genus Halobates Eschscholtz (Hemiptera : Gerridae), of Australia: Taxonomy, phylogeny and zoogeography

Abstract

The sea skaters, genus Halobates Eschscholtz, include the only known oceanic insects, although most species of Halobates are found in sheltered coastal waters. The present paper deals with the 11 species known from Australian waters, divided into two subgenera, Hilliella China and Halobates s. str., and the latter into 5 species-groups. Characters found useful in forming these species-groups include: interocular width of head, head colour markings, relative lengths of fore tarsal segments, mesotibio-tarsal hair fringe, structure of male genital segments, and vesical armature. The cladistic relationships among species and species-groups are analysed and discussed. A key to the species of Australian Halobates is provided. All species endemic to Australia are redescribed and their distribution recorded and mapped. Taxonomic and distributional notes are given for the remaining species. H. (Hilliella) lannae is described as new from the Northern Territory, and the synonymies H. australiensis Malipatil (= H. hayanus White) and H. ashrnorensis Malipatil (= H. princeps White) are verified. Finally, we discuss the ecological diversity and zoogeography of Australian sea skaters.