TY - JOUR
T1 - Evolution, Systematics, and Phylogeography of Pleistocene Horses in the New World: A Molecular Perspective
AU - Weinstock, Jaco
AU - Willerslev, Eske
AU - Sher, A.
AU - Tong, Wenfei
AU - Ho, Simon Y. W.
AU - Rubenstein, Dan
AU - Storer, John
AU - Burns, James
AU - Martin, Larry
AU - Bravi, Claudio
AU - Prieto, Alfredo
AU - Froese, Duane
AU - Scott, Eric
AU - Xulong, Lai
AU - Cooper, Alan
PY - 2005
Y1 - 2005
N2 - The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.
AB - The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.
U2 - 10.1371/journal.pbio.0030241
DO - 10.1371/journal.pbio.0030241
M3 - Journal article
C2 - 15974804
VL - 3
SP - e241-e248
JO - PLoS Biology
JF - PLoS Biology
SN - 1544-9173
IS - 8
ER -