Staphylinidae is one of the most diverse groups of animals, with more than 58,000 described species placed in one extinct and 32 extant subfamilies. Jurassic rove beetles are mainly reported from the Late Jurassic of Karatau, Kazakhstan. Here we report an unusual rove beetle, Mesapatetica aenigmatica n. gen. n. sp., from the Middle Jurassic (ca. 165 Ma) of China. The new species displays an enigmatic combination of features belonging to the two basal subfamilies Apateticinae (e.g., clubbed antennae, keeled tibiae, and well-margined pronotum) and Trigonurinae (e.g., presence of epistomal suture, more or less reduced antennomere 8, relatively long elytra covering abdominal tergite III, and body shape). It also has several peculiar features lacking in those subfamilies: contiguous mesocoxae, and abdominal tergites IV and V each with a pair of basolateral ridges. The discovery of this enigmatic genus from the Middle Jurassic reinforces the hypothesis that Apateticinae and Trigonurinae are sister taxa and together form one of the earliest lineages of Staphylinidae.