A revision of Peltariosilis Wittmer (Coleoptera: Cantharidae), a surprisingly diverse Amazonian radiation

Abstract

Peltariosilis Wittmer, 1952 is a South American Silinae genus characterised by the highly modified male pronotum and scutellum with a remarkable lamellar projection. Six species were previously recognised. The study of numerous specimens from previously unsampled localities and the revision of previously studied material shows that Peltariosilis is far more diverse than previously recognised. 15 species are here recognised as valid, nine of which are described as new: P. brancuccii, P. brunneoapicalis, P. cleidecostae, P. diversicollis, P. flavicornis, P. gracilicornis, P. major, P. orientalis and P. parviscutellaris spp. nov. A comparative study and new morphological terminologies are introduced for pronotum, scutellum and male genitalia. All Peltariosilis species are described and illustrated, including the first illustration of a female pronotum, and an identification key is provided. A map is given, including records of all known Peltariosilis, showing a distribution confined to the Amazonian subregion (Suriname, French Guiana, N Brazil, E Peru and NE Bolivia). The identity of the type species P. scutulata (Wittmer, 1952), hitherto considered as broadly distributed and highly variable, is addressed through study of their type series and additional specimens from widespread localities.