Mammalia 72 (2008): 2–14  2008 by Walter de Gruyter • Berlin • New York. DOI 10.1515/MAMM.2008.004 Article in press - uncorrected proof 2007/4 Review Afrotherian mammals: a review of current data Rodolphe Tabuce 1, *, Robert J. Asher 2 and Thomas Lehmann 3 1 Institut des Sciences de l’Evolution, cc064, Universite ´ Montpellier II, place Euge ` ne Bataillon, 34095 Montpellier cedex 05, France, e-mail: rtabuce@isem.univ-montp2.fr 2 Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK 3 Museum fu ¨ r Naturkunde der Humboldt-Universita ¨ t zu Berlin, Forschungsabteilung Invalidenstrasse 43, 10115 Berlin, Germany *Corresponding author Abstract The supraordinal mammalian clade Afrotheria was first recognized in its entirety based on DNA analysis dating to the mid-1990s. Since then, this ‘‘African clade’’, which includes proboscideans, sirenians, hyracoids, tubuliden- tates, elephant-shrews, tenrecs and chrysochlorids, has been supported by numerous molecular and genomic studies. According to these molecular inferences, the ori- gin of crown Afrotheria goes back into the Cretaceous, with estimates from over 100 to under 80 Mya. Morpho- logical phylogenies have not completely recovered Afro- theria, although its paenungulate core (proboscideans, sirenians and hyracoids) was named in 1945 by the pale- ontologist George Simpson. Recent paleontological studies concur with molecular ones in evoking some affinities between paenungulates, aardvarks and ele- phant-shrews. Moreover, the position of tenrecs and golden moles within afrotherians is supported by some recent concatenations of morphological and molecular phylogenetic datasets. The phylogenetic position of Afro- theria relative to the other supraordinal placental clades has been debated, the most recent analyses of genomic and concatenated data support a basal position within Placentalia. Molecular data suggest an African origin for Afrotheria and a long period of endemism on that conti- nent. When adding the paleontological data to this sce- nario, the paleobiogeographic history of Afrotheria becomes more complex. For instance, these data argue for the broad distribution of afrotherians during the Ter- tiary and do not exclude their Laurasian origin. In fact, some Laurasian taxa could be closely related to the ear- liest afrotherians (hyracoids, proboscideans and ele- phant-shrews) found in the early Eocene of North Africa. Other Afrotherian groups are known with certitude from East Africa since the beginning of the Miocene. Keywords: fossil record; molecules; morphology; phylogeny. Introduction The resolution of the phylogenetic relationships among mammalian placental orders and the question of when and where the eutherian radiation took place is a contro- versial topic between morphologists (including paleon- tologists) and molecular biologists. Molecular analyses, based on large nuclear gene datasets strongly support the division of living placental lineages into four superor- dinal groups: Afrotheria, Xenarthra, Euarchontoglires and Laurasiatheria (Murphy et al. 2001a,b, Scally et al. 2001, Amrine-Madsen et al. 2003, Springer et al. 2004, Niko- laev et al. 2007, Nishihara et al. 2007, Springer and Murphy 2007, Wildman et al. 2007) (Figure 1). The clade Afrotheria includes six placental orders: Proboscidea (elephants), Sirenia (dugongs and manatees), Hyracoidea (hyracoids), Macroscelidea (elephant-shrews), Tubuliden- tata (aardvarks) and Tenrecoidea (tenrecs and golden moles, also known as ‘‘Afrosoricida’’). According to these analyses, these taxa evolved and have been in Africa since the Cretaceous. Compared to the overwhelming molecular and geno- mic support for Afrotheria (Redi et al. 2007, Springer and Murphy 2007), the available morphological data are equivocal concerning the validity of such a clade. The different Afrotherian orders have long been scattered among ungulates (proboscideans, sirenians, hyracoids and tubulidentates), lipotyphlan insectivores (tenrecids and chrysochlorids), or considered as the sister group of glires (macroscelids). One explanation for this disagree- ment between molecules and morphology is the sup- posed long endemic evolution of afrotherians that may have overwritten morphological afrotherian synapomor- phies (Robinson and Seiffert 2004). According to the fos- sil record, afrotherians have indeed a long history on the Afro-Arabian continent. Likewise, their living representa- tives are mostly present in Afro-Arabia and Madagascar, except for the Asian elephant, West Indian and Amazo- nian manatees, and Australasian dugongs. The study of the earliest afrotherians, and eutherians in general, is thus important because they provide direct evidence of the order of acquisition of characters. These fossils pres- ent character combinations absent in modern taxa, and they allow the study of characters that have been ‘‘erased’’ by subsequent evolution within a clade (Benton 1995). In that regard, the recent studies of such fossil euthe- rians on one hand (Zack et al. 2005, Tabuce et al. 2007, Wible et al. 2007), and the mapping of several morpho- logical characters observed on living afrotherians on molecular phylogenies on the other hand (Werdelin and Nilsonne 1999, Whidden 2002, Cox 2006, Mess and Carter 2006, Sa ´ nchez-Villagra et al. 2007) have revealed