Eocontosceles gen. nov., the first fossil of Thaumastodinae from mid-Cretaceous Kachin amber (Coleoptera: Limnichidae)

The beetle subfamily Thaumastodinae is a morphologically distinctive lineage within Limnichidae, but has not previously been recorded in the fossil record. Here, we report the first fossil representative of Thaumastodinae, Eocontosceles pollocki gen. et sp. nov., preserved in mid-Cretaceous Kachin amber from northern Myanmar. Eocontosceles exhibits a characteristic thaumastodine appearance and most closely resembles the extant genus Acontosceles Champion. However, it is unique within the subfamily in possessing unreduced 5-5-5 tarsi, subfiliform antennae lacking a club, and margined grooves near mouthparts that are not associated with antennae. As an early-diverging lineage of Thaumastodinae, Eocontosceles provides crucial insight into the basal morphology and evolutionary history of the group.