Researches on the Quaternary insects faunal changes in Japan

Abstract

In order to elucidate the transition of insect fauna of the Japanese archipelago, Pliocene to Pleistocene fossil insects were surveyed in the Japanese main islands. As a result, it was found that extinct and extant species coexisted in the Pliocene to Early Pleistocene. Most extinct species are thought to have been extinct at the end of the Early Pleistocene to Middle Pleistocene. In particular, the abundant fossil records of Donaciinae leaf beetles (Coleopetera, Chrysomelidae) show that the records of the extant species include “old extant species” dating back to the Pliocene to Early Pleistocene and “new extant species” appearing in the Middle Pleistocene. The transition of the beetle fauna was divided into four ages. The time when the recent Donaciinae fauna were almost completed is after the Middle Pleistocene. Also, the time axis of the molecular phylogenetic tree was set, and the speciation age was estimated, based on the fossil record of the extant species.