Evolution of North American mountain goats and bighorn sheep in China and North America

Ever since doing his dissertation on the extinct mountain goats that inhabited the Grand Canyon and elsewhere in the intermountain west, Dr. Jim Mead has pursued the evolution of North American bovids (bison, mountain goats, bighorn sheep, musk-ox, and fossil relatives). It is known that all of the native and fossil bovids in North America dispersed from northeastern Asia into the Western Hemisphere. Some forms entered North America long enough ago that they too have evolved into new forms unique to the continent.

Extinct mountain goat (Oreamnos harringtoni)

The skull fragment of Sinocapra willdownsi dating to 4.95-4.7 Ma, earliest Pliocene, Nevada.

The earliest bovid in North America, Neotragocerus, was described in 1909 and was alive in the latest Miocene, about 6 million years ago. Mead described the next oldest bovid in North America – Sinocapra willdownsi – from the earliest Pliocene (4.9 million years old) from Nevada. The name refers to a genus of Chinese goat, now also known from North America. Now Mead and Oklahoma Museum of Natural History colleague, Nick Czaplewski, are describing a new genus and species of diminutive mountain sheep recovered from sediments dating about 2.5 million years old in southeastern Arizona.

The key to North American bovids is eastern Russia and China. Recent work in Renzidong Cave by Chinese paleontologist Dr. Changzhu Jin (Director, Cenozoic Mammals, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing) has unearthed new bovid remains. Dr. Jin has requested that Mead visit Beijing to analyze and publish on these new Pliocene-age remains. With a grant from the American Philosophical Society, Mead and Sandra Swift will begin work on the new bovids sometime during the late summer, 2006. The trip will also begin a new collaboration on the faunas and archaeology from many caves in the Chang Jiang Valley, Anhui Province, west of Shanghai.