REVIEW The record of Cenozoic horses in Mexico: current knowledge and palaeobiological implications Jaime Priego-Vargas 1 & Victor Manuel Bravo-Cuevas 2 & Eduardo Jiménez-Hidalgo 3 Received: 1 July 2015 /Revised: 1 October 2015 /Accepted: 19 November 2015 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2016 Abstract Fossil horses in Mexico have been documented for 150 years. At present, there exists an abundant and diverse record that deserves consideration. In this contribution, we offer an overview of the current knowledge on the fossil hors- es in Mexico. The Mexican record of the family Equidae in- cludes early horses and representatives of the subfamilies Anchitheriinae and Equinae. The diversity of horses in Mexico includes 15 genera and 28 species with ages ranging from early Eocene to late Pleistocene. The record of the sub- family Equinae from the upper Neogene and Quaternary de- posits from central Mexico represents the largest proportion of fossil horse evidence in the country. Of the species observed within the Mexican territory, 75 % were at their southernmost extent in North America. The Mexican record shows that a considerable portion of the evolutionary history of horses occurred in Mexico. Nevertheless, the study of fossil horses in Mexico is ongoing. Therefore, including the Mexican specimens in studies using biogeographical, evolutionary and ecological approaches will considerably improve our knowledge of horses in southern North America. Keywords Equidae . Diversity . Cenozoic . Mexico . Palaeobiology Introduction Horses are well represented in the Cenozoic fossil record in North America. This group of perissodactyls constitutes an important element in the mammalian associations of that geo- chronological segment (mainly in the Neogene and Quaternary faunas) (MacFadden 1992), and it has been stud- ied at different levels, including taxonomy and systematics (Webb and Hulbert 1986; Hulbert 1993; Kelly 1995; Froehlich 2002), evolution (Simpson 1944; Stirton 1947; Romer 1949; MacFadden 2005), phylogeny (Hulbert 1993; Prado and Alberdi 1996 ; Kelly 1998), biogeography (Colbert 1935; MacFadden and Skinner 1979; Bernor et al. 1980; Woodburne et al. 1981; Maguire and Stigall 2008, 2009; Stigall 2008), and palaeoecology (Hulbert 1984; Gingerich 1989; MacFadden et al. 1999; Mihlbachler et al. 2011). Furthermore, horses have been deemed a model for understanding macroevolutionary processes, such as adaptive radiation, speciation, rates of morphological change, trends, dispersal and extinction (Matthew 1926; Simpson 1944; Lindsay et al. 1980, Lindsay 1984; MacFadden 1988, 1992, 2005; MacFadden and Hulbert 1988; Hulbert and MacFadden 1991; Hulbert 1993; Carroll 1998). Current information indicates that the evolution of the fam- ily Equidae was extremely complex and very different from the orthodox vision of gradual transition, from primitive, low- crowned and four-toed horses (e.g. Eohippus) to advanced * Jaime Priego-Vargas jpriego123@yahoo.com.mx Victor Manuel Bravo-Cuevas vmbc1@yahoo.com Eduardo Jiménez-Hidalgo eduardojh@zicatela.umar 1 Doctorado en Ciencias en Biodiversidad y Conservación, área Académica de Biología, Universidad Autónoma del Estado de Hidalgo, Ciudad del Conocimiento, Carretera Pachuca-Tulancingo km 4.5, CP 42184 Pachuca, Hidalgo, Mexico 2 Museo de Paleontología, área Académica de Biología, Universidad Autónoma del Estado de Hidalgo, Ciudad del Conocimiento, Carretera Pachuca-Tulancingo km 4.5, CP 42184 Pachuca, Hidalgo, Mexico 3 Laboratorio de Paleobiología, Instituto de Recursos, Campus Puerto Escondido, Universidad del Mar, Carretera Puerto Escondido-Oaxaca km 2.5, CP 71980 Oaxaca, Mexico Palaeobio Palaeoenv DOI 10.1007/s12549-015-0223-y