New World proboscidean extinctions: comparisons between North and South America

摘要

In South America, generally accepted dates place humans in coastal Chile and Patagonia ca. 13,000 BP and sites no older than ca. 11,000 BP are common in other areas. Gomphotheres become extinct in the late Pleistocene, probably after humans arrived and as climate changed. However, bone dates suggest that in many regions of South America, especially the Pampean region of Argentina and Uruguay (ca. 21,000 to 18,000 BP), gomphotheres already were gone when the first humans arrived. Although gomphothere remains are present at Monte Verde and other sites, they do not appear to have been important for human subsistence. In North America, human presence also is accepted around 11,500 BP. Gomphotheres range throughout much of M,xico into the US Southwest. Very few places are known with dated Quaternary gomphotheres, and most of them are considered paleontological localities rather than archeological sites. A small number of reliable associations between Clovis artifacts and proboscideans correspond to Mammuthus and Mammut remains. Controversial human evidence has been proposed for Valsequillo (Puebla, M,xico), where gomphotheres coexisted with mammoth and mastodons. Recent findings in northern Sonora, on more secure grounds, point to a human-gomphothere relationship around 11,000 BP. No human-gomphothere association is documented in the USA. Gomphotheres apparently survive until the end of the Pleistocene, but certainly those survivors were unique relict populations. Gomphothere extinction is driven more by climate and ecosystem changes than through human interactions.