Jurassic artematopodid beetles and their implications for the early evolution of A rtematopodidae ( C oleoptera)

Fossil A rtematopodidae are rarely collected and previously confined to middle E ocene B altic amber. Here we report the first definitive artematopodid, S inobrevipogon jurassicus gen. et sp.n. , from the M iddle J urassic D aohugou beds ( c . 165 Ma) in I nner M ongolia, northeastern C hina. It exhibits a number of defining features of A rtematopodidae, including paired carinae on prosternum and an internal apical interlocking tongue on the ventral side of each elytron. However, it differs from any modern A rtematopodidae 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 A rtematopodidae, highlighting the antiquity of the family. The systematic positions of Forticatinius T an & R en and Tarsomegamerus Z hang are discussed, and the latter is formally transferred to A rtematopodidae. Phylogenetic relationships within A rtematopodidae were investigated to elucidate the relationships between the two J urassic genera and R ecent 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 A rtematopodidae in three clades: (i) Electribius authority , (ii) Ctesibius authority +  Brevipogon authority +  Sinobrevipogon  +  Tarsomegamerus and (iii) the remaining R ecent genera, including A llopogonia authority .