Palaeoecology of the Mammoth Steppe fauna from the late Pleistocene of the North Sea and Alaska: Separating species preferences from geographic influence in paleoecological dental wear analysis

摘要

The paleodietary ecology of Late Pleistocene ungulate faunas of the Mammoth Steppe ecosystem was investigated at Fairbanks (Alaska) and Brown Bank (North Sea) through dental mesowear and microwear analysis. The purpose of the study is to address questions concerning the paleoecology of the Mammoth Steppe, an ecosystem that has no extant analog. Dental wear patterns indicate that the niche partitioning at Brown Bank (BB) region was consistent with ecosystem dynamics found in diverse ungulate faunas in recent time. In contrast, despite the lower numbers of extinct taxa, the Fairbanks (FB) fauna is ecologically bizarre. In general, the microwear of this fauna includes excessive numbers of very (narrow) fine scratches that are atypical for extant mixed feeders and grazers. Moreover, the mesowear signal suggests unusual paleodiets (niche dynamics), where low-crowned mixed-feeding cervids, Rangifer and Cervus, adopted diets that are similar to Equus in terms of mesowear (abrasion) and much more abrasive than the diets of either Bison or Ovis. We suggest that the anomalies may relate to unique, possibly disharmonious, ecosystem dynamics during the Pleistocene-Holocene transition. In addition to these findings, it was discovered (found) that dental wear patterns, particularly microwear variables such as scratch frequency and scratch width are strongly affected by geographic region, irrespective of species-specific dietary preferences.