A new aquatic beetle (Adephaga: Coptoclavidae) from the Middle Jurassic Daohugou Biota.

Tigrivia baii gen. et sp. nov. (Coleoptera: Adephaga: Coptoclavidae) is described and named based on a fossil specimen from the Middle Jurassic Daohugou Biota, Nincheng County, Inner Mongolia of China. The fossil is very similar in morphology with the adult Coptoclava longipoda Ping 1928 (Laiyang Formation of Nanligezhuang Village, Laiyang City, Shandong Province, China, Lower Cretaceous, 121 ~ 120 Ma), but differs from C. longipoda by the adjacencies of two procoxae and two mesocoxae. T. baii gen. et sp. nov. differs from Daohugounectes primitinus Wang et al. 2010 by the absence of striae on the elytra and the absence of ventral eyes under the head. The new beetle species shows developed aquatic adaptions, such as specialized raptorial forelegs, and swimming middle and hind legs. Furthermore, it is speculated to lead a similar lifestyle as extant Dytiscoidae, according to the two eyes on the side of head and the absence of spiracles on ventrites. This new fossil expanded our knowledge of the diversity of the Middle Jurassic Coptoclavid beetles in Daohugou Biota and improved our understanding of their paleoecological significance.