The oldest fossil Ochodaeidae (Coleoptera: Scarabaeoidea) from the Middle Jurassic of China Author Ren, Dong text Zootaxa 2010 2553 65 68 journal article 10.5281/zenodo.196844 2fb3fe46-d3e3-4cda-a575-b7a8caa1b5d4 1175-5326 196844 Mesochodaeus new genus ( Figs. 1 , 2 ) Higher taxon names: Coleoptera : Polyphaga: Staphyliniformia: Scarabaeoidea : Ochodaeidae . Family Ochodaeidae Mulsant & Rey, 1871 ; subfamily incertae sedis. Type species: Mesochodaeus daohugouensis sp. nov. ; Middle Jurassic, Daohugou beds, Ningcheng County, Inner Mongolia in China . Here designated. Etymology: The name of the new genus refers to the era of its origin and the generic name Ochodaeus Dejean, 1821 (the type genus of this family); gender masculine. Diagnosis and description: In additional to the species description given below, this genus can be diagnosed by the mandibles externally rounded, visible beyond labrum in dorsal view; mesocoxae appear to be contiguous (but probably very narrowly separated in life); mesotibiae with 2 or 3 transverse carinae along outer edge. Composition: The type species only. Remarks: It is impossible to determine an exact position of the genus Mesochodaeus within the family, because the structure of the mesotibial and metatibial spurs, wing venation, and a number of other key taxonomic characters are unknown.