title: Oligocene mammals from Ethiopia and faunal exchange between Afro-Arabia and Eurasia.
abstract: Afro-Arabian mammalian communities underwent a marked transition near the Oligocene/Miocene boundary at approximately 24 million years (Myr) ago. Although it is well documented that the endemic paenungulate taxa were replaced by migrants from the Northern Hemisphere, the timing and evolutionary dynamics of this transition have long been a mystery because faunas from about 32 to 24 Myr ago are largely unknown. Here we report a late Oligocene fossil assemblage from Ethiopia, which constrains the migration to postdate 27 Myr ago, and yields new insight into the indigenous faunal dynamics that preceded this event. The fauna is composed of large paenungulate herbivores and reveals not only which earlier taxa persisted into the late Oligocene epoch but also demonstrates that one group, the Proboscidea, underwent a marked diversification. When Eurasian immigrants entered Afro-Arabia, a pattern of winners and losers among the endemics emerged: less diverse taxa such as arsinoitheres became extinct, moderately species-rich groups such as hyracoids continued into the Miocene with reduced diversity, whereas the proboscideans successfully carried their adaptive radiation out of Afro-Arabia and across the world.
authors.affiliation: Department of Anthropology, University of Texas, Austin, Texas 78712, USA. jkappelman@mail.utexas.edu
authors.forename: John
authors.initials: J
authors.lastname: Kappelman
authors.forename: D Tab
authors.initials: DT
authors.lastname: Rasmussen
authors.forename: William J
authors.initials: WJ
authors.lastname: Sanders
authors.forename: Mulugeta
authors.initials: M
authors.lastname: Feseha
authors.forename: Thomas
authors.initials: T
authors.lastname: Bown
authors.forename: Peter
authors.initials: P
authors.lastname: Copeland
authors.forename: Jeff
authors.initials: J
authors.lastname: Crabaugh
authors.forename: John
authors.initials: J
authors.lastname: Fleagle
authors.forename: Michelle
authors.initials: M
authors.lastname: Glantz
authors.forename: Adam
authors.initials: A
authors.lastname: Gordon
authors.forename: Bonnie
authors.initials: B
authors.lastname: Jacobs
authors.forename: Murat
authors.initials: M
authors.lastname: Maga
authors.forename: Kathleen
authors.initials: K
authors.lastname: Muldoon
authors.forename: Aaron
authors.initials: A
authors.lastname: Pan
authors.forename: Lydia
authors.initials: L
authors.lastname: Pyne
authors.forename: Brian
authors.initials: B
authors.lastname: Richmond
authors.forename: Timothy
authors.initials: T
authors.lastname: Ryan
authors.forename: Erik R
authors.initials: ER
authors.lastname: Seiffert
authors.forename: Sevket
authors.initials: S
authors.lastname: Sen
authors.forename: Lawrence
authors.initials: L
authors.lastname: Todd
authors.forename: Michael C
authors.initials: MC
authors.lastname: Wiemann
authors.forename: Alisa
authors.initials: A
authors.lastname: Winkler
mesh_terms: D025041:Animal Migration; D000818:Animals; D001083:Arabia; D001208:Asia; D044822:Biodiversity; D005075:Biological Evolution; D005002:Ethiopia; D005060:Europe; D005580:Fossils; D019015:Geologic Sediments; D008322:Mammals / Q000033:anatomy & histology / Q000145:classification; D014070:Tooth / Q000033:anatomy & histology