DIVERSITY OF THE FOSSIL EQUIDS FROM SOUTH AMERICA

Abstract

The contemporary mammalian communities of South America were defined by the rise of the Isthmus of Panama and by the deep climatic oscillations during the Pleistocene. Horses are a conspicuous group of North American immigrant mammals that came to South America during the late Pliocene and did not survive the great megafauna extinction approximately twelve thousand years ago. The present study compiles updated data on the phylogeny, systematics and ecology of this group in South America. The first lineage is represented by the genus Equus, which appears in the Middle Pleistocene and presents anatomical features similar to those of a current horse. The second lineage is the species included in the genus Hippidion, which were horses with highly distinctive anatomical features that were first recorded in the late Pliocene. Both genera of horses include small (H. devillei, H. saldiasi, E. andium and E. insulatus) and large (E. neogeus and H. principale) forms, which dispersed in South America using two different routes. The possible model for this dispersal indicates that the small forms used the corridor of the Andes, while the larger horses dispersed along the eastern route and some coastal areas.

Keywords

• Perissodactyla
• Equidae
• Pliocene
• Pleistocene
• South America