Jurassic artematopodid beetles and their implications for the early evolution of Artematopodidae (Coleoptera)

Fossil Artematopodidae are rarely collected and previously confined to middle Eocene Baltic amber. Here we report the first definitive artematopodid, Sinobrevipogon jurassicus gen. et sp.n. , from the Middle Jurassic Daohugou beds (c. 165 Ma) in Inner Mongolia, northeastern China. It exhibits a number of defining features of Artematopodidae, including paired carinae on prosternum and an internal apical interlocking tongue on the ventral side of each elytron. However, it differs from any modern Artematopodidae by having the mesocoxal cavitiy closed by the mesepimeron and the anterolateral edge of metanepisternum. The discovery of this new genus represents the earliest fossil record for Artematopodidae, highlighting the antiquity of the family. The systematic positions of Forticatinius Tan & Ren and Tarsomegamerus Zhang are discussed, and the latter is formally transferred to Artematopodidae. Phylogenetic relationships within Artematopodidae were investigated to elucidate the relationships between the two Jurassic genera and Recent genera. Eleven in‐group taxa and two out‐groups were included in a cladistic analysis based on 30 adult characters; the resulting tree recovered the family Artematopodidae in three clades: (i) Electribius authority, (ii) Ctesibius authority + Brevipogon authority + Sinobrevipogon + Tarsomegamerus and (iii) the remaining Recent genera, including Allopogonia authority.