A new genus of giant sooty mould beetles from mid-Cretaceous Burmese amber (Coleoptera: Cyclaxyridae)

Abstract

The sooty mould beetles (Cyclaxyridae) are a small and relictual family of cucujoid beetles with only two extant species restricted to New Zealand. The systematic position of the family within Cucujoidea is unresolved, with morphological and molecular studies yielding a range of incongruent topologies. Here we describe a new cyclaxyrid genus and species, Pacyclaxyra azari gen. et sp. nov., from mid-Cretaceous Burmese amber mined in northern Myanmar (ca. 99 Ma). The new genus is separated from all other cyclaxyrids by its unusually large body size, dorsally concealed antennal insertions, narrowly separated procoxae, narrow prosternal process not expanded at apex, and presence of a distinct discrimen on metaventrite. Together with Electroxyra cretacea described from the same deposit, Pacyclaxyra gen. nov. represents the earliest sooty mould beetle in the fossil record. Considering the potentially plesiomorphic characters possessed by Pacyclaxyra azari gen. et sp. nov., the implications for understanding the systematic position of Cyclaxyridae are discussed.