When the formation of the Isthmus of Panama linked North America and South America, a massive migration of mammals took place, and a study analyzing a database of fossils finds that the main reason behind a greater diversity of mammals with North American ancestry found in South America than vice-versa was likely the disproportionate extinction of native South American mammals during the biotic interchange.
Article #20-09397: "Disproportionate extinction of South American mammals drove the asymmetry of the Great American Biotic Interchange," by Juan D. Carrillo et al.
MEDIA CONTACT: Juan D. Carrillo, National Museum of Natural History, Paris, FRANCE; e-mail: juan.carrillo@mnhn.fr
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Proceedings of the National Academy of Sciences