Potential distribution of hybrids between [i]Crocodylus acutus[/i] and [i]Crocodylus moreletii[/i] on the Mexican Pacific coast outside the natural hybridisation zone

Abstract

In Mexico, Crocodylus acutus is widely distributed along the Pacific coast, while C. moreletii occurs on the Gulf of Mexico. Both species converge in the Yucatán peninsula where natural hybridisation is reported, and later it was also reported in the Gulf of Mexico. Unfortunately, due to translocations and stochastic events, currently there are hybrids of both species on the coast of Oaxaca and Guerrero. In this study, we evaluated the potential colonisation areas of the hybrids on the Pacific coast through ecological niche analyses. The results indicate that the hybrid crocodiles and the parent species share preferences in at least three climatic variables: average temperature range, isothermality, and minimum temperature of the coldest month. Furthermore, it was found that the climatic niche of the hybrids is more similar to that of the C. moreletii leaving reminiscent areas for C. moreletii in Nuevo León, San Luis Potosí and small areas far from the coast in Veracruz, coinciding with what was previously reported by molecular analysis. On the other hand, the climatic niche of the hybrid crocodiles is also sufficiently similar to that of C. acutus, having the possibility to colonise the Pacific coast extensively, leaving reminiscent small areas for C. acutus on the northern coast of Sinaloa, southern of Sonora, central coast of Oaxaca and small inland areas of the Pacific coast. Keywords: Crocodilians, ecological niche, hybrids, species model distributions, conservation, Mexico