Cladistic analysis and taxonomic revision of the scutellaris group of Palpada Macquart (Diptera:Syrphidae)

Abstract

Palpada Macquart, 1834 is a large genus of tropical Eristaliini flies with distribution restricted to the New World (Diptera : Syrphidae : Eristalinae). Most species were initially placed within Eristalis Latreille, 1804. In 1972, most Neotropical species were transferred to Palpada when F.C. Thompson divided Eristalis sensu lato into three genera: Eristalis, Eoseristalis Kanervo, 1938 and Palpada. The latter genus was divided by Thompson (1981) into three groups of species: scutellaris, agrorum and vinetorum. In the present study, the species of the scutellaris group are revised and the phylogenetic relationships among its species are reconstructed based on adult morphology. The cladistic analysis of the 24 terminal species and 48 characters of external morphology and male and female genitalia, produced one cladogram under equal weights. The monophyly of the scutellaris group was corroborated. Twelve species are recognised within the group, of which one is described as new: Palpada cordiformis Morales, sp. nov., P. claudia (Curran), P. conica (Fabricius), P. doris (Curran), P. erratica (Curran), P. fuliginosa (Hull), P. megafemur Thompson, P. melanaspis (Wiedemann), P. precipua (Williston), P. rufoscutellata (Sack), P. scutellaris (Fabricius) and P. vera (Hull). Two new synonymies are proposed: P. dorothea (Hull, 1942) = P. melanaspis (Wiedemann, 1830); and P. glabella (Hull, 1942) = P. fuliginosa (Hull, 1935). The lectotype is designated for Eristalis melanaspis. An identification key, a catalogue, distribution maps, illustrations of general aspects, illustrations of male and female genitalia and scanning electron micrographs are provided.