WHAT DO WE KNOW ABOUT THE PHYLOGENY OF THE SEMI-AQUATIC BUGS (HEMIPTERA: HETEROPTERA: GERROMORPHA)?

The present study summarizes knowledge about phylogenetic relationships of the heteropteran infraorder Gerromorpha. A phylogeny for all families and subfamilies, and for all genera but those assigned to the two most diverse families, Veliidae and Gerridae, is compiled from the many studies by the late Dr. Nils Moller Andersen. Comparisons with recently published studies, including DNA sequence data show that the superfamilies Hydrometroidea and Gerroidea, the family Veliidae, the subfamily Mesoveliinae, and the genera Mesovelia and Microvelia are probably not monophyletic, and that Paraphrynoveliidae, Gerridae, Madeoveliinae, Ocelloveliinae, Veliinae, Haloveliinae and Gerrinae are without convincing diagnostic morphological characters. In Gerridae, phylogenetic hypotheses are available for most subfamilies, and are evaluated against more recent studies indicating that the tribes Metrocorini and Metrobatini, and even well-known genera, such as Aquarius, Limnometra, Tenagogonus and Halobates, are not monophyletic. As taxonomic classifications should be based on observable morphological characters, and at the same time reflect phylogenetic relationships, a considerable task lays ahead in obtaining material of key taxa for DNA sequencing, and in identifying and redescribing clades based on new combinations of diagnostic characters.