We report here ecological and morphological characterization of the main Old World Equus in North America, Asia, Europe, and Africa, by comparing the studied fossil forms with the living Equus grevyi zebra. Equus simplicidens from North America, Equus livenzovenzis, Equus stenonis, and Equus stehlini from Italy, Equus sivalensis from India, Equus cf. stenonis and a small Equus from Georgia (Caucasus), Equus oldowayensis, Equus koobiforensis, and Equus cf. tabeti from Kenya and the extant Equus grevyi are described in their cranial and dental features and are compared in morphological postcranial dimensions by means of log10 ratio analysis. The occurrence of the two horses at the Dmanisi Homo site in Georgia is reported here for the first time. Our comparative analyses allow to confirm the primitive lineage of the ancient zebras as derived from Equus simplicidens, and the successive evolution of the stenonine horses in Asia, South Asia, and Europe during the Plio—Pleistocene. The morphological analysis has reveals a clear trend in third metacarpals and third metatarsals of E. simpicidens, the small Equus from Dmanisi and E. grevyi, suggesting a close relationship between these species. The trend of the stenonine Equus from Europe and Asia confirms the possible derivation from the North America Equus simplicidens. The description of all the Old World Equus is integrated with an overview of their paleoecological context, with a referred section for each locality where these fossils were found. This contribution represents a comprehensive review of the present knowledge of the Old World Equus evolutionary history, with some new important data in deciphering the deep origin and evolution of ancient and living zebras.

Studies of horse evolution arose during the middle of the 19th century, and several hypotheses have been proposed for their taxonomy, paleobiogeography, paleoecology and evolution. The present contribution represents a collaboration of 19 multinational experts with the goal of providing an updated summary of Pliocene and Pleistocene North, Central and South American, Eurasian and African horses. At the present time, we recognize 114 valid species across these continents, plus 4 North African species in need of further investigation. Our biochronology and biogeography sections integrate Equinae taxonomic records with their chronologic and geographic ranges recognizing regional biochronologic frameworks. The paleoecology section provides insights into paleobotany and diet utilizing both the mesowear and light microscopic methods, along with calculation of body masses. We provide a temporal sequence of maps that render paleoclimatic conditions across these continents integrated with Equinae occurrences. These records reveal a succession of extinctions of primitive lineages and the rise and diversification of more modern taxa. Two recent morphological-based cladistic analyses are presented here as competing hypotheses, with reference to molecular-based phylogenies. Our contribution represents a state-of-the art understanding of Plio-Pleistocene Equus evolution, their biochronologic and biogeographic background and paleoecological and paleoclimatic contexts.

We undertake a redescription of the equid sample from the Early Pleistocene of Roca-Neyra, France. This locality has been recently calibrated at the Pliocene/Pleistocene boundary (2.6 ± 0.2 Ma) and therefore it is of interest for the first appearance of the genusEquusand last appearance of hipparionine horses. The Roca-Neyra equid sample, re-analyzed herein using morphological, morphometrical, and statistical analyses, has revealed the co-occurrence ofPlesiohipparioncf. ?P.rocinantisandEquuscf.E.livenzovensis. The analysis undertaken on several European, African, and Asian “Hipparion” sensu lato species from late Miocene to Early Pleistocene has revealed different remnantHipparionlineages in the Plio-Pleistocene of Europe:Plesiohipparion,Proboscidippaion, and likelyCremohipparion. The discovery of the first European monodactyl horse,Equuscf.E.livenzovensiscorrelates Roca-Neyra with other 2.6 Ma European localities in Italy, Spain, and in the Khapry area (Azov Sea region). The morphological description of theEquuscf.E.livenzovensislower cheek teeth has highlighted intermediate features between the North American Pliocene speciesEquus simplicidensand Early Pleistocene EuropeanEquus stenonis. Our study supports the hypothesis thatE.livenzovensisis a plausible evolutionary predecessor for theEquus stenonisgroup. These observations underscore the importance of Roca-Neyra as an important locality for the last European hipparions and the firstEquusin the Early Pleistocene of Europe.

This chapter summarizes recent advances in paleobiological research of the Late Miocene Maragheh fauna in northwest Iran. The Maragheh fauna has long been considered one of the three most preeminent western Eurasian Late Miocene Pikermian faunas, along with those of Samos and Pikermi in Greece. Between 2007 and 2009, Iran's National Museum of Natural History collaborated with the University of Helsinki launched an initiative, known as the International Sahand Paleobiology Expedition (INSPE), resulting in the discovery of several new localities and numerous fossils of land mammals in the area. The program has further reinitiated studies of the mammalian fauna with the intention of bringing them into a contemporary taxonomic context for comparative paleoecological and paleobiogeographic studies. This chapter describes the geology and stratigraphy of the Maragheh Basin and the sedimentary horizons of the Maragheh Group as they are expressed in the Maragheh Basin, along with the area's paleontology, chronology, paleobiogeography, and paleoecology.

The Early Pliocene locality of Çalta, Turkey (Ruscinian Age, c. 4.0 Ma) has two species of advanced hipparionine horses that we refer to Plesiohipparion cf. longipes (Gromova, 1952) and Proboscidipparion heintzi (Eisenmann & Sondaar, 1998). Our study follows an extensive treatment of the entire mammalian fauna in 1998 and in particular an important and comprehensive work on the hipparions by Eisenmann & Sondaar in 1998. We undertake herein a morphologic and metric analysis of skulls, mandibles, dentitions and postcranial elements to segregate all elements into these two taxa. Our analysis follows and concurs with Eisenmann & Sondaar's work except for the generic attributions here which are original. Beyond the basic empirical work here, we strike comparisons to other Old World hipparion lineages and find that these two hipparion taxa compare closely, at the genus level, to Asian Plesiohipparion Qiu, Huang & Guo, 1987 and Proboscidipparion Sefve, 1927. Our comparisons further elucidate that Plesio... RÉSUMÉ Plesiohipparion and Proboscidipparion (Equidae, Hipparionini) du Pliocène inférieur de Çalta, Turquie (Ruscinien, c. 4.0 Ma). Le gisement de Çalta se situe en Anatolie centrale en Turquie et il est corrélé au Pliocène inférieur (Ruscinien, c. 4,0 Ma). Il a livré deux espèces d'hipparions à caractères dérivés que nous appelons Plesiohipparion cf. longipes (Gromova, 1952) et Proboscidipparion heintzi (Eisenmann & Sondaar, 1998). La faune de Çalta a fait l'objet d'une étude intégrale en 1998 et, dans ce contexte, Eisenmann & Sondaar ont décrit en détail les hipparions de ce site. Nous proposons ici une analyse morphologique et biométrique de crânes, mandibules, dentitions et éléments postcrâniens appartenant à ces deux taxons. Notre analyse est en accord avec le travail de Eisenmann & Sondaar, sauf pour les attributions génériques qui sont ici reconsidérées. Au-delà du travail empirique de base, nous avons effectué des comparaisons avec d'autres lignées d'hipparions de l'Ancien Monde et constaté que c...

The Hippopotamidae have been a major component of the African wetland fauna for the last 7 million years, following the ‘Hippopotamine Event,’ i.e., the sudden emergence in the fossil record of the subfamily Hippopotaminae, including both extant species. The general dearth of African fossiliferous deposits dated between 9.5 Ma and 7.5 Ma concealed until now the evolution that led to the Hippopotamine Event and the subsequent success of these large semiaquatic herbivores. Part of this evolution is unveiled by the hippopotamid dental remains found at Chorora, a late Miocene site of the southern Afar Depression in Ethiopia spanning most of the fossil-depleted time interval. Although fragmentary, these remains represent a new, mid-sized hippopotamid species dated to ca. 8 Ma, as well as a somewhat younger, larger form. A cladistic analysis of a large array of cetartiodactyls indicates that the Chorora taxa were basal to the latest Miocene hippopotamines. The new species displays a mosaic of dental characters that support the attribution of the new species to a new genus within Hippopotaminae. The new fossils also clarify the course of early hippopotamine dental evolution. The Chorora hippopotamids suggest that transition to a marked abundance of hippopotamines with their unique dental pattern in African ecosystems occurred within a relatively short time interval, most probably between 8 Ma and 7.5 Ma. http://zoobank.org/urn:lsid:zoobank.org:pub:47B9381F-E3B5-40C9-B9AB-51CC3D0D3A8A SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Boisserie, J.-R., G. Suwa, B. Asfaw, F. Lihoreau, R. L. Bernor, S. Katoh, and Y. Beyene. 2017. Basal hippopotamines from the upper Miocene of Chorora, Ethiopia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1297718.