Oxyporinae is one of the most peculiar and distinguishable groups of the megadiverse family Staphylinidae, and it includes only one extant genus Oxyporus and nearly 100 extant species widely distributed in the Northern Hemisphere. Members of Oxyporus exhibit an obligate association with mature Agaricales (gilled), Boletales (bolete) and Polyporales (polypore) mushrooms, and both larvae and adults feed on the spore-producing layer of the mushrooms. Mesozoic record of Oxyporinae is very limited, with only one Oxyporus species described from the Yixian Formation at Beipiao, Liaoning Province.
Recently, a PhD student Mr. CAI Chenyang and Prof. HUANG Diying from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences reported two distinctly different oxyporine rove beetles (Fig. 1) from the Yixian Formation (ca. 125 Ma) at Liutiaogou, Ningcheng County, Inner Mongolia and Huangbanjigou, Beipiao, Liaoning Province China. Based on detailed morphological study, including the application of SEM, remarkable differences are found between the extinct and extant oxyporines, and two new genera and species, Protoxyporus grandis and Cretoxyporus extraneus, were established. Protoxyporus differs from extant Oxyporus in retaining several plesiomorphic features: relatively narrowly separated mesocoxae, less developed metaventral anterior process, and long infraorbital ridges. Cretoxyporus is morphologically very similar to Oxyporus, but retains distinct elongate infraorbital ridges. Extant oxyporines are fed on some derived fungi (Fig. 2), and fungi were already differentiated and diverse in the Cretaceous; it is possible that the new oxyporines were lived on early mushrooms. It also suggests that the early oxyporines were more diverse and their evolutionary history more complicated than previously documented.
This research was supported by the National Basic Research Program of China, Outstanding Youth Foundation of Jiangsu Province, and the National Natural Science Foundation of China.
Related information of the paper: Chenyang Cai, Diying Huang (2014) Diverse oxyporine rove beetles from the Early Cretaceous of China (Coleoptera: Staphylinidae). Systematic Entomology, DOI: 10.1111/syen.12069.
Fig. 1. Cretaceous oxyporine rove beetles (upper) and the abdominal intersegmental “brick-wall” pattern (lower)
Fig. 2. Representatives of modern oxyporine rove beetles
