The oldest Tenebrionidae (Coleoptera) of the subfamily Diaperinae and the tribe Scaphidemini from the Paleocene of Menat (France)

Keywords: diversification of Diaperini and Scaphidemini, new species and genus, fossil tenebrionids, Tenebrionidae


The oldest tenebrionid beetle Palaeobasanus neli gen. et sp. n. of the tribe Scaphidemini (subfamily Diaperinae) is described from the Paleocene of Menat (Thanetian) in France. The new extinct genus shows a distinct complex of characters of the tribe Scaphidemini, such as modified procoxal cavities, modified prosternal “cowling” and mesocoxal cavities partly closed by mesepimera. Palaeobasanus gen. n. differs from the extant Scaphidemini in the narrowly separated coxae, structure of prosternal process, which is moderately narrow at middle but strongly widened at apex and rounded (not truncate), abdominal intercoxal process, antennomeres 4–7 clearly covered by simple trichoid sensilla but without round sensory complexes as in recent Scaphidemini and Diaperini. All these mentioned characters seem to be symplesiomorphies within the tenebrionoid lineage, including oldest Mesozoic ‘tenebrionoid’ darkling beetles. It is thought that Palaeobasanus gen. n. could be a basal group within Scaphidemini, closely related to Diaperini, which probably existed at least in the border of the Mesozoic and Cenozoic.