­­­­­Taxonomic revision and morphological phylogeny of the endemic leafhopper genus Nesocerus (Hemiptera: Cicadellidae: Idiocerinae) from Madagascar

The recent Terrestrial Arthropods of Madagascar inventory project conducted by the California Academy of Sciences and Tsimbazaza Botanical and Zoological Park has revealed that large numbers of Malagasy leafhopper species, including many species of Nesocerus, remain to be described. The Malagasy endemic genus Nesocerus Freytag & Knight, 1966 is reviewed. The genus is distributed throughout Madagascar in various habitats including humid forests, littoral forests, coastal sandy dunes and dry deciduous forests, but appears to be most diverse in eastern humid forests. A phylogenetic analysis based on sixty five adult morphological characters of 41 taxa was performed to test the monophyly of the genus and to examine relationships among the species of Nesocerus. The present study revealed 29 new species, thereby increasing total number of species to 35 based on external and male genitalia characters. We found three additional characters for the identification of the genus. Phylogenetic analysis suggests that monophyly of the genus is well supported. Within Nesocerus, the analysis recovered two sister clades, one comprising species mostly distributed in the eastern rainforests of Madagascar, and the other including species mainly restricted to the dry western region of Madagascar. The analysis did not resolve the relationship of Nesocerus to other Idiocerini unambiguously, but some unique derived features of the forewing and male genitalia suggest that the closest relatives of Nesocerus may include taxa from South Asia and South America.