Timing of megafaunal extinction in the late Late Pleistocene on the Japanese Archipelago

Abstract

In the late Late Pleistocene (lLP), Japanese terrestrial large mammals consisted of two main groups; the Palaeoloxodon-Sinomegaceroides complex and the mammoth fauna. The former inhabited temperate forests and the latter were adapted to patches of taiga and grassland in cold environments. Among the two groups, almost all large mammals became extinct in the Late Quaternary. The lLP extinction is one of the most interesting topics currently debated in Japan.This paper evaluates previously reported radiocarbon dates of mammal fossils to determine the timing of lLP megafaunal extinctions on the Japanese Archipelago. Unreliable specimens which were dated by conventional 14C decay counting, samples obtained from poorly preserved fossils, samples inconsistent with geological context, and samples dated by combining bone fragments of several species and whose exact provenances are unknown are rejected. The timing of extinctions was compared with the vegetational changes. As a result, the present paper indicates that the extinction of large mammals in the Palaeoloxodon-Sinomegaceroides complex roughly coincided with the onset of the last glacial maximum (LGM: from ca. 25,000 BP to 16,000 BP) and subsequent domination by subarctic conifers. In contrast, the mammoth fauna survived the LGM and became extinct or migrated northward when the climate started to ameliorate. The lLP extinction on the Japanese Islands occurred in two pulses. These results imply that the main causes of lLP extinction on the Japanese Archipelago were changes of the ecosystem driven by climatic changes rather than “overkill” by human hunters.