Coptoclavid beetles (Insecta: Coleoptera: Adephaga) from the Triassic of Lower Franconia, Germany

Abstract

Many fossils of water beetles of the family Coptoclavidae have been found unexpectedly among insect fossils from the Middle Triassic (Anisian) and Upper Triassic of Franconia, Germany. Very small (about 3 mm long) beetles with longitudinal dark stripes on the elytra, similar in coloration pattern to beetles of the genus Holcoptera Handlirsch, 1906 from the terminal Triassic and Lower Jurassic of England and Lower Jurassic of the United States, have been found in Anisian deposits. Similar but larger beetles (about 5 mm long) have been found in Keuper (Carnian) deposits, in which they occur much more frequently than in Anisian localities, even dominating some of these localities. Unfolded or fragmentary hindwings that also belong to beetles of the same species and match the elytra in size have also been found. There are no known localities in which so many beetle hindwings occur, especially hindwings of the same species. They are described here as wings of Coptoclavidae. A small incomplete larva matching these beetles in size has also been found. The beetles are described as representatives of a new genus of the subfamily Coptoclaviscinae. In addition to them, the larvae of a rather large coptoclavid Protonectes Prokin et Ponomarenko, 2013 was described earlier from the same deposits; it is assigned here to the subfamily Timarchopsinae. Only two elytra with numerous fine grooves not bearing any punctures match this larva in the available collection. Similar elytra were described earlier from the Jurassic of Europe and Siberia as Dinoharpalus Handlirsch, 1906. A small elytron with many grooves was described in the same genus from the terminal Permian of Eastern Europe. Similar elytra are known in coptoclavids described from the Lower Cretaceous of Spain as Hispaniclavina. The presence of such advanced beetles as coptoclavids as early as the Lower Anisian shown that the famous Permian–Triassic crisis was not so deep as it is usually believed, and many beetles survived it, disappearing, however, from the fossil record in the Early Triassic. Keywords: insects, beetles, Triassic