Description and 3D imaging of a new Quasicalathus species from Eocene amber (Coleoptera, Carabidae)

A new fossil species of the genus Quasicalathus preserved in Eocene amber is described using light microscopy, micro-CT scanning and 3D visualization. It differs from the previously described species mainly by the shape of the aedeagal median lobe and its right paramere, with the latter characterized by presence of a distinct apical hook. Our morphological findings suggest that Quasicalathus is a representative of a Sphodrini clade which is sister group to the subtribe Sphodrina and comprises the Calathina, Dolichina, Pristosiina, and Synuchina. The discovery of the new species highlights the importance of microCT technology for the analysis of beetle fossils preserved in amber.