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Morphological diversity of the American crocodile (Crocodylus acutus) in the Yucatán Peninsula

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Abstract

Recent evidence suggests that morphological divergence of the American crocodile (Crocodylus acutus) occurred in Greater Antilles under conditions of prolonged isolation and hybridization with the Cuban crocodile (C. rhombifer). We investigated morphological diversity in C. acutus in the coastal zone of the Yucatán Peninsula, where isolation and hybridization have also been reported. We compared the relationships among various morphological traits between insular and coastal populations. Our results suggest morphological diversity in the region, which is possibly related to population isolation and mechanical constraints imposed by differences in diet. A broad-snouted morphotype appears typical of island populations. Hybridization could also cause morphological variation, but its importance in this case remains to be confirmed. Sexual dimorphism of the American crocodile in the region appears to be less pronounced than for other crocodilians. We also provide population-specific size estimation models for two populations (Banco Chinchorro and Cozumel) to improve future monitoring.

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Acknowledgments

Fieldwork conducted at Banco Chinchorro and Cozumel was funded by El Colegio de la Frontera Sur (ECOSUR), Fundación de Parques y Museos de Cozumel, Proyecto PAPIIT UNAM (IN215011-3), Xcalak to Chinchorro Diver Center, Transbordadores del Caribe and the Centro del Cambio Global y de la Sustentabilidad en el Sureste; field work in Belize was funded by grants from the United Nations Development Program, Global Environment Facility, Wildlife Conservation Society, and the Oceanic Society. Field work conducted in the coast of Mexico was funded by El Colegio de la Frontera Sur (ECOSUR) and the Wildlife Trust (Reference Log No. 01-02-168), and by fellowships and grants awarded to JRCV from the Consejo Nacional de Ciencia y Tecnología (CONACYT) and the World Wildlife Fund (WWF) through the Russell E. Train Education for Nature program. PC received a bilateral Mexico-France doctoral scholarship (22/BFE/2005 457761B) from the Secretaria de Relaciones Exteriores de México and the Ministère des Affaires Étrangères de France (2006–2008), together with a post-doctoral scholarship from the Programa de Becas Posdoctorales, Universidad Nacional Autónoma de México (2011–2013). TR was supported by the Yawkey Foundation and Clemson University. We are particularly grateful to the many people who assisted the field work, and Pablo J. Ramírez-Barajas for providing two crocodile skulls for measurements. We would also like to thank Marco Festa-Bianchet, Marc Bélisle and the anonymous referees for their constructive comments on earlier versions of the paper and Jill Vandermeerschen for her support in data analysis. This paper represents Technical Contribution No. 6532 of the Clemson University Experiment Station.

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  1. Didier Labarre

    Present address: Département des Sciences Biologiques, Université du Québec à Montréal, 141 Avenue du Président-Kennedy, Montreal, QC, Canada

Authors and Affiliations

  1. Département de Biologie, Faculté des Sciences, Université de Sherbrooke, 2500, Boulevard de l’Université, Sherbrooke, QC, Canada

    Didier Labarre

  2. Centro del Cambio Global y la Sustentabilidad en el Sureste A.C., Calle Centenario del Instituto Juárez, S/n, Colonia Reforma, C.P. 86080, Villahermosa, Tabasco, Mexico

    P. Charruau

  3. Wildlife Conservation Society - Myanmar Program, No. 12, Nanrattaw St., Kamayut Township, Yangon, Myanmar

    S. G. Platt

  4. Tom Yawkey Wildlife Center and Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC, 29440, USA

    T. R. Rainwater

  5. Departmento de Sistemática y Ecología Acuática, El Colegio de la Frontera Sur, Av. Centenario Km 5.5, 77014, Chetumal, Quintana Roo, Mexico

    J. R. Cedeño-Vázquez

  6. Fundación de Parques y Museos de Cozumel, Av. Lic. Pedro Joaquin Coldwell 70, 77600, San Miguel de Cozumel, Quintana Roo, Mexico

    H. González-Cortés

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  1. Didier Labarre
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Correspondence to Didier Labarre.

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Authors do not have any conflicts of interest to declare and insure that every precaution for animal welfare was taken. The Secretaria de Medio Ambiente y Recursos Naturales of Mexico provided the scientific research permits for crocodile captures (Oficios Núm. SGPA/DGVS/02932/06, 02188/07, 02066/08, 02516/09, 00724/10, 04528/11, 03366/12, 03080/13).

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Labarre, D., Charruau, P., Platt, S.G. et al. Morphological diversity of the American crocodile (Crocodylus acutus) in the Yucatán Peninsula. Zoomorphology 136, 387–401 (2017). https://doi.org/10.1007/s00435-017-0356-9

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