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Low Levels of Nucleotide Diversity in Crocodylus moreletii and Evidence of Hybridization with C. acutus

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Abstract

Examinations of both population genetic structure and the processes that lead to such structure in crocodilians have been initiated in several species in response to a call by the IUCN Crocodile Specialist Group. A recent study used microsatellite markers to characterize Morelet's crocodile (Crocodylus moreletii) populations in north-central Belize and presented evidence for isolation by distance. To further investigate this hypothesis, we sequenced a portion of the mitochondrial control region for representative animals after including samples from additional locales in Belize, Guatemala and Mexico. While there is limited evidence of subdivision involving other locales, we found that most of the differentiation among populations of C. moreletiican be attributed to animals collected from a single locale in Belize, Banana Bank Lagoon. Furthermore, mitochondrial DNA sequence analysis showed that animals from this and certain other locales display a haplotype characteristic of the American crocodile, C. acutus, rather than C. moreletii. We interpret this as evidence of hybridization between the two species and comment on how these new data have influenced our interpretation of previous findings. We also find very low levels of nucleotide diversity in C. moreletiihaplotypes and provide evidence for a low rate of substitution in the crocodilian mitochondrial control region. Finally, the conservation implications of these findings are discussed.

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Author notes

  1. Steven G. Platt

    Present address: Wildlife Conservation Society, 2300 Southern Blvd., Bronx, NY, 10460-1099, US

Authors and Affiliations

  1. Department of Biological Sciences, MS 3131, Texas Tech University, Lubbock, TX, 79409, USA

    David A. Ray, Adam G. Finger, Scott T. McMurry & Llewellyn D. Densmore

  2. Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA, 70803, USA

    David A. Ray & Mark A. Batzer

  3. University of San Francisco, Harney Science Center, Room 342, 2130 Fulton St., San Francisco, CA, 94117, USA

    Jennifer A. Dever

  4. The Institute of Environmental and Human Health, Texas Tech University, Box 41163, Lubbock, TX, 79409-1163, USA

    Thomas R. Rainwater

  5. National Geographic Society, 1145 17th St. NW, Washington, DC, 20036, USA

    Brady Barr

  6. The Natural History Museum, Cromwell Road, London, SW7 5BD, UK

    Peter J. Stafford

  7. Department of Biology, University of Miami, Coral Gables, FL, 33124, USA

    Jenna McKnight

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  1. David A. Ray
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Ray, D.A., Dever, J.A., Platt, S.G. et al. Low Levels of Nucleotide Diversity in Crocodylus moreletii and Evidence of Hybridization with C. acutus . Conservation Genetics 5, 449–462 (2004). https://doi.org/10.1023/B:COGE.0000041024.96928.fe

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