The enigmatic Nearctic genus Ceramphis Casey revisited (Coleoptera, Staphylinidae, Scydmaeninae)

Abstract

Ceramphis Casey is the only genus of Scydmaenini restricted to North America. Despite previous redescriptions of the only included species, C. deformata (Horn), not all taxonomically important structures have been illustrated, and consequently morphological affinities with other Scydmaenini genera remain unclear. Ceramphis deformata is redescribed with exoskeletal features documented by scanning electron microscopy. Similarities and differences in relation to all remaining Scydmaenini (preliminarily subdivided into three groups of genera) are discussed. Differences between Ceramphis and Scydmaenus seem rather minor and Ceramphis, apart from its unusual body shape, closely resembles a group of several subgenera of Scydmaenus characterized by the metanepisterna fused with the metaventrite. However, unclear taxonomy of Scydmaenus with its 30 ill-defined subgenera makes it impossible to decide whether Ceramphis should be maintained as a genus or reduced to a subgenus of Scydmaenus. For this reason, status of Ceramphis remains unchanged, until a comprehensive revision and phylogenetic analysis of the Adrastia-Ceramphis-Scydmaenus group of genera has been carried out.