Genetic diversity, species phylogeny and historical biogeography of the Aquarius paludum group (Heteroptera : Gerridae)

We investigated genetic diversity and phylogeny of all water strider species assigned to the Aquarius paludum species group on basis of 425 bp DNA sequence data from the mitochondrial gene encoding cytochrome oxidase subunit I (COI). Parsimony analyses and genetic distances confirmed the taxonomic status of the two recently described species Aquarius lili Polhemus & Polhemus, 1994 from Timor and A. philippinensis Zettel & Ruiz, 2003 from the Philippines as being separate from the widespread Oriental A. adelaidis (Dohrn, 1860). Molecular clock estimates suggest that the disjunct zoogeographical pattern among the three species is due to a Pliocene/Pleistocene long-range dispersal, rather than a Mesozoic vicariance event as previously suggested. However, when we superimposed the disjunct distribution of Southern Hemisphere representatives of the paludum-group onto their phylogenetic relationship, the pattern indicated vicariance events following the break-up of Gondwana.