title: Anthracothere dental anatomy reveals a late Miocene Chado-Libyan bioprovince.
abstract: Recent discovery of an abundant and diverse late Miocene fauna at Toros-Ménalla (Chad, central Africa) by the Mission Paléoanthropologique Franco-Tchadienne provides a unique opportunity to examine African faunal and hominid evolution relative to the early phases of the Saharan arid belt. This study presents evidence from an African Miocene anthracotheriid Libycosaurus, particularly well documented at Toros-Ménalla. Its remains reveal a large semiaquatic mammal that evolved an autapomorphic upper fifth premolar (extremely rare in Cenozoic mammals). The extra tooth appeared approximately 12 million years ago, probably in a small northern African population isolated by climate-driven fragmentation and alteration of the environments inhabited by these anthracotheriids [Flower, B. P. & Kennett, J. P. (1994) Palaeogeogr. Palaeoclimatol. Palaeoecol. 108, 537-555 and Zachos, J., Pagani, M., Sloan, L., Thomas, E. & Billups, K. (2001) Science 292, 686-693]. The semiaquatic niche of Libycosaurus, combined with the distribution and relationships of its late Miocene species, indicates that by the end of the Miocene, wet environments connected the Lake Chad Basin to the Libyan Sirt Basin, across what is now the Sahara desert.
authors.affiliation: Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine, Unité Mixte de Recherche Centre National de la Recherche Scientifique (UMR CNRS) 6046, Université de Poitiers, 86022 Poitiers Cedex, France. fabrice.lihoreau@univ-poitiers.fr
authors.forename: Fabrice
authors.initials: F
authors.lastname: Lihoreau
authors.forename: Jean-Renaud
authors.initials: JR
authors.lastname: Boisserie
authors.forename: Laurent
authors.initials: L
authors.lastname: Viriot
authors.forename: Yves
authors.initials: Y
authors.lastname: Coppens
authors.forename: Andossa
authors.initials: A
authors.lastname: Likius
authors.forename: Hassane Taisso
authors.initials: HT
authors.lastname: Mackaye
authors.forename: Paul
authors.initials: P
authors.lastname: Tafforeau
authors.forename: Patrick
authors.initials: P
authors.lastname: Vignaud
authors.forename: Michel
authors.initials: M
authors.lastname: Brunet
mesh_terms: D000818:Animals; D001641:Bicuspid; D002596:Chad; D002980:Climate; D003817:Dentition; D005580:Fossils; D049690:History, Ancient; D015186:Hominidae / Q000502:physiology*; D008002:Libya; D010161:Paleodontology; D010802:Phylogeny; D013997:Time Factors