New species of Xiphoscelis Burmeister, 1842 (Coleoptera, Scarabaeidae, Cetoniinae) from arid regions of South Africa and Namibia

Abstract

Two new species of the southern African genus Xiphoscelis Burmeister, 1842 are recognised and described, X. braunsi sp. nov. from the Eastern and Western Cape Karoo (South Africa) and X. namibica sp. nov. from the Huns Mountains of southern Namibia and adjacent ranges in South Africa. These were previously overlooked and grouped together with X. schuckardi Burmeister, 1842, but further material and more in-depth analyses have now revealed their clear separation on the basis of key diagnostic features, including clypeal structure, metatibial spur development and aedeagal shape. The densely and coarsely costate elytral structure and the black to brown colour of these species are symplesiomorphies shared with a number of the most primitive genera among the African Cetoniinae. However, these characters also reflect the convergent adaptation to hot and arid conditions they share with several other species occurring in this region. Phylogenetic relationships of the genus with other Cetoniinae are explored using the larval characters highlighted in the description of the 3rd instar larva of X. braunsi sp. nov. The extraordinary hypertrophy observed in the male metatibial spur of species in this genus, and particularly in X. schuckardi, appears to represent a defence mechanism against potential predators on the ground, apart from playing a role during mating.