99 Historical and ecological biogeography of the genus Crotalus in Mexico Uriel Hernández-Salinas 1 , Aurelio Ramírez-Bautsta 2 , Gustavo Montel-Canales 2 & Raciel Cruz-Elizalde 2 1 Insttuto Politécnico Nacional, CIIDIR Unidad Durango, Sigma 119, Fraccionamiento 20 de Noviembre II, Durango, Durango 34220, México 2 Laboratorio de Ecología de Poblaciones, Centro de Investgaciones Biológicas, Insttuto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Km 4.5 carretera Pachuca-Tulancingo, 42184, Mineral de La Reforma, Hidalgo, México Herpetological Journal FULL PAPER Correspondence: Aurelio Ramírez Bautsta (ramibautstaa@gmail.com) Volume 26 (January 2017), 99–108 Published by the Britsh Herpetological Society The genus Crotalus is well represented in all biogeographic provinces including most major vegetaton communites and climatc zones described for Mexico. For this reason, we use the assumptons of panbiogeography with the objectve to establish a biogeographic framework for the 26 species of ratlesnakes natve to Mexico. On the basis of 1472 records, 26 individual tracks derived from the distributon of each species resulted in two generalised tracks. The frst is located in the Peninsula of Baja California, in the biogeographic provinces of California and Baja California, and is identfed by three species (C. enyo, C. mitchellii and C. ruber). The second generalised track is located on the eastern porton of the Transmexican Volcanic Belt, the Balsas Basin, and Sierra Madre del Sur, supported by C. ravus and C. intermedius. An analysis of partton of variance found that vegetaton explains the most variaton in the distributon of species. Very similar results were obtained by analysis of ancestral reconstructon for biogeographic provinces, vegetaton types and elevaton. Our results are consistent with diferent climatc events during the Pleistocene, and tectonic events such as the lifing of the Sierra Madre Occidental and Sierra Madre Oriental. In additon, our results showed similarites with historical distributons of birds, mammals and beetles. Further studies of the distributon and phylogeography of other groups of reptles with signifcant informaton gaps in their historical and current distributon are needed to shed further light on the biogeography and diversity of reptles of Mexico. Key words: biogeographic provinces, distributon, ecology, panbiogeography, Ratlesnakes INTRODUCTION T he genus Crotalus belongs to the family Viperidae and is composed of 35 extant species (Wilson et al., 2013). Of these, 26 species are found in Mexico, where 22 species (63% of the total diversity in the genus) are endemic (Douglas et al., 2006; Wilson et al., 2013). Members of this genus occur in tropical lowland provinces of the Gulf of Mexico, the Pacifc Coast, the Yucatán Peninsula, and the montane provinces of the Sierra de Chiapas and the Sierra Madre del Sur, as well as the temperate forests of the Sierra Madre Oriental, Sierra Madre Occidental and Transmexican Volcanic Belt, and arid areas of northern Mexico (the Sonoran, Baja California and California provinces) and the Mexican Plateau at elevatons up to 4,000 m a.s.l. (Smith & Taylor, 1966; Klauber, 1972; Campbell & Lamar, 2004). The distributon of the genus Crotalus is of partcular interest to biologists and geologists interpretng evidence of historical interglacial fuctuatons, such as regional temperatures, and duraton of glacial eras during the Pleistocene (Klauber, 1972; Douglas et al., 2006). The ranges of extant Crotalus species have also previously been shown to resemble paterns observed in non-fying mammals for example (Bryson et al., 2011a,b, 2014; Douglas et al., 2006; Escalante et al., 2007), but studies that integrate distributon paterns with aspects of climate, vegetaton and elevaton are largely lacking so far. Panbiogeography is a tool that can be used to describe paterns of historical distributon of complex groups occurring in one or more geographical areas, where the presence of each species in diferent biogeographic provinces and vegetaton types refects its current ecological distributon (Klauber, 1972; Morrone, 2015). In this study, we analysed the historical and ecological relatonships of the 26 Crotalus species of Mexico, using the variance parttoning method and an analysis of ancestral character state reconstructon (Morrone et al., 2002). MATERIAL AND METHODS Sources of informaton We obtained geographical records for members of the genus Crotalus from a database of amphibians and