Taxonomic redefinition and natural history of the endemic silphid beetle Silpha longicornis (Coleoptera: Silphidae) of Japan, with an analysis of its geographic variation

A taxonomic redefinition of Silpha longicornis Portevin, 1926 is presented and the lectotype of S. longicornis is designated. Silpha yamatona Kôno, 1929 and Silpha imitator Shibata, 1969 are synonymized with S. longicornis based on examination of their type specimens and the geographic pattern of mtDNA CO1 region collected from representative localities in Japan, including their type localities. A key for the northeast Asian members of the Silpha carinata group is presented, and the geographic distribution, life cycle, microhabitat, and feeding biology of S. longicornis are summarized. Body size and elytral colors and sculptures are influenced by climatic conditions, and this morphological variation conformed to Gloger’s rule and the converse of Bergmann’s rule.