Sesión de carteles de la 27ª del Comité de Fauna (AC27) y 21ª del Comité de Flora (PC21) de la Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres (CITES) 28 de abril al 8 de mayo de 2014
Natural hybridization between Crocodylus moreletii and C. acutus with a rapid and wide expansion in the Gulf of Mexico and the Caribbean: The first step towards a speciation event of crocodiles in Mexico?
2Conservación, Manejo y Aprovechamiento Sustentable de Flora y Fauna Silvestre A.C. (COMAFFAS)
3Utah State University (USU)
Natural interspecific hybridization plays an important role in conservation and evolutionary biology, and may also contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and facilitate speciation. Previous studies have shown that hybridization processes are occurring between Crocodylus moreletti and Crocodylus acutusin the Yucatan Peninsula, Mexico, along their historic area of sympatry. Considering ecological and behavioral characteristics that we have observed in hybrid individuals, four our genetic study we hypothesize that: a) genetic analysis will show that the hybridization process between C. moreletii and C. acutus has been occurring throughout the Gulf of Mexico and the Caribbean and b) we will find evidence of isolation by distance and aggressive expansion of admixture individuals as a first step to reproductive isolation, which could potentially promote adaptive divergence of hybrids and eventually speciation. We sampled 188 crocodiles along the Gulf of Mexico and the Caribbean and amplified nine microsatellites. We applied Bayesian and maximum-likelihood statistical analysis to evaluate hybridization, introgression and genetic isolation. Results show that the process of hybridization between C. moreletii and C. acutus is happening in most of the evaluated species’ range. We found evidence of isolation by distance and of expansion of admixed individuals. Our work supports our hypotheses and may provide the basis for different management and conservation plans for these species of crocodiles in Mexico, especially within the CITES context.