Emergência de parentes de elefantes no Paleoceno e a radiação rápida de ungulados africanos

Paleocene emergence of elephant relatives and the rapid radiation of African ungulates

1. Emmanuel Gheerbrant,1

+Author Affiliations

1. Unité Mixte de Recherche 7207, Centre National de la Recherche Scientifique, Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements, Case 38, Département Histoire de la Terre, Muséum National d'Histoire Naturelle, 8, Rue Buffon, 75005 Paris, France

1. Edited by Elwyn L. Simons, Duke University Lemur Center, Durham, NC, and approved May 11, 2009 (received for review January 14, 2009)

Abstract

Elephants are the only living representatives of the Proboscidea, a formerly diverse mammalian order whose history began with the 55-million years (mys) old Phosphatherium. Reported here is the discovery from the early late Paleocene of Morocco, ca. 60 mys, of the oldest and most primitive elephant relative, Eritherium azzouzorum n.g., n.sp., which is one of the earliest known representatives of modern placental orders. This well supported stem proboscidean is extraordinarily primitive and condylarth-like. It provides the first dental evidence of a resemblance between the proboscideans and African ungulates (paenungulates) on the one hand and the louisinines and early macroscelideans on the other. Eritherium illustrates the origin of the elephant order at a previously unknown primitive stage among paenungulates and “ungulates.” The primitive morphology of Eritherium suggests a recent and rapid paenungulate radiation after the Cretaceous-Tertiary boundary, probably favoured by early endemic African paleoecosystems. At a broader scale, Eritherium provides a new old calibration point of the placental tree and supports an explosive placental radiation. The Ouled Abdoun basin, which yields the oldest known African placentals, is a key locality for elucidating phylogeny and early evolution of paenungulates and other related endemic African lineages.

* Africa-Morocco
* Afrotheria
* Paenungulata
* Placentalia
* Proboscidea

Footnotes

1 To whom correspondence should be addressed. E-mail: gheerbra@mnhn.fr

Author contributions: E.G. designed research, performed research, analyzed data, and wrote the paper.

The author declares no conflict of interest.

This article is a PNAS Direct Submission.

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