Abstract
The Philippine crocodile (Crocodylus mindorensis) is considered one of the most endangered of the crocodilian species.Rumors or anecdotal concerns have existed for some time as to the possibility of hybrid individuals existing in a captivecollection under consideration for providing reintroduction candidates; however, visual observations failed to identify sus-pected hybrids. Samples were collected from 619 Philippine crocodiles from several captive facilities and two free-rang-ing populations. Mitochondrial DNA D-loop (601 bp) fragments were sequenced for each crocodile and compared to 28individuals representing ten crocodile species. Among Philippine crocodiles, 48 variable sites (47 parsimony informativesites) were identified, which defined six C. mindorensis haplotypes and one C. porosus-derived haplotype. Data were alsogenerated for a 965 bp fragment of the ND4 subunit gene fragment for two samples of each D-loop haplotype. Amongthem, 91 variable sites (90 parsimony informative site) were identified, which defined three C. mindorensis haplotypesand one C. porosus-derived haplotype. From the nuclear genome, the C-mos gene was successfully amplified for the 388bp partial fragment for all Philippine crocodile samples. Only two variable sites were identified. These sequences werecompared to GenBank sequences for C. porosus. Of the 619 Philippine crocodile samples, 57 samples were found to har-bor D-loop haplotypes identified as C. porosus and 31 of those harbored C-mos mutational sites diagnostic for C. porosusintrogression. All individuals indicating C. mindorensis x C. porosus hybridization were sampled from the Palawan Wildlife Rescue and Conservation Center.References
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