Molecular phylogeny of selected eurasian podismine grasshoppers (orthoptera: acrididae)

Abstract

The grasshopper subfamily Melanoplinae, comprising a large number of genera and species, maintains a distribution throughout Eurasia and the New World. Despite various attempts to subdivide the subfamily, taxonomic assignments within the Melanoplinae remain unclear. However, the placement of Eurasian and related Nearctic genera within a separate tribe, Podismini, is a common feature within most proposed taxonomic schemes. The Podismini have been independently divided into two and four subtribes on the basis of cytogenetic and morphological traits, respectively; however, the two schemes differ with respect to the placement of certain genera. This study analyses sequence data obtained from portions of four mitochondrial genes (cyt b, COII, ND2, and COI) to (1) test the hypothesis that Eurasian podismines are monophyletic and (2) examine which, if any, of the proposed subtribal affiliations is correct. The view that the nominate genus, Podisma, represents a form closely related to the ancestral podismine stock was also examined. Parsimony, neighbor-joining, and likelihood tree construction methods demonstrate strong support for claims of Eurasian podismine monophyly. Application of the molecular clock method places the separation from North American melanoplines at ≈62 mya. Neither cytogenetic nor morphological subtribal assignations of genera within Podismini is supported by molecular data. Lastly, our analysis shows that Podisma, rather than occupying a basal position among the podismines as suggested in the literature, is a more recently evolved genus. © 2001 Entomological Society of America.