A new giant megatheriine ground sloth (Mammalia : Xenarthra :Megatheriidae) from the late Blancan to early Irvingtonian of Florida

摘要

The giant megatheriine ground sloth Eremotherium eomigrans is described based on remains from the late Blancan to early Irvingtonian (late Pliocene to early Pleistocene) of Florida. It resembles the other giant megatheriines E. laurillardi and Megatherium americanum in size, but is clearly distinguished by a pentadactyl manus. It is assigned to the genus Eremotherium based on two synapomorphies shared with E. laurillardi: a coarse and rugose ectotympanic that ventrally is prominently expanded mediolaterally, and contiguous articular facets of the axis for the atlas. E. eomigrans is the earliest megatheriine known to have migrated to North America across the Panamanian Land Bridge during the Great American Interchange. (C) 1999 The Linnean Society of London.