Phylogenetic analysis of American Rhagovelia Mayr, 1865 (Insecta: Heteroptera: Veliidae)
Gerromorpha, phylogeny, Neotropical region, semiaquatic bugs
Members of the genus Rhagovelia Mayr, 1865 (Hemiptera: Heteroptera: Gerromorpha:
Veliidae: Rhagoveliinae) are commonly found in aquatic habitats of tropical regions,
comprising the dominant guild of predatory insects of the neustonic fauna of rivers,
streams and creeks in these areas. The genus is recognizable by the distal tarsomere of
its middle leg deeply forked and bearing a feathery fan that aids in moving on running
water. The genus is one of the most diverse of Gerromorpha, with about 200 described
species in the Americas alone. Currently, the American fauna of the genus is subdivided
into 18 species groups, which in turn comprise one grade (paraphyletic) and five
complexes (monophyletic), in addition to species without defined positioning. Although
the monophyly of the genus is recovered in all phylogenetic analysis performed so far,
the relationships between such supraspecific groupings and their monophyly have never
been truly tested. Based on the examination of the literature and of 156 specimens
distributed in 42 species and 11 groups, 81 discreet morphological characters, of which
68 are binary and 13 are multistate, have been surveyed and coded for the American
fauna of Rhagovelia. A phylogenetic analysis performed through heuristic search using
TNT 1.5 no taxon limit resulted in 10 most parcimonious trees with 194 steps, and once
again corroborated the monophyly of the genus. In a strict consensus cladogram
generated based on these trees, apart from the itatiaiana group, it was possible to
visualize two large monophyletic groups, one containing species with short pronotum
and the other, species with long pronotum. This partially corroborates the proposal that
exists in the literature for defining a subgenus Neorhagovelia Matsuda, 1956 for those
species that are today gathered in the abrupta grade and in the angustipes complex, in
oposition to those of the subgenus Rhagovelia s. str., which compose the remaining
species groups.