Publication Date:
2018-11-12
Description:
Four species of true crocodile (genusCrocodylus) have been described from the Americas. Three of these crocodile species exhibit non-overlapping distributions—Crocodylus intermediusin South America,C. moreletiialong the Caribbean coast of Mesoamerica, andC. rhombiferconfined to Cuba. The fourth,C. acutus, is narrowly sympatric with each of the other three species. In this study, we sampled 113 crocodiles acrossCrocodyluspopulations in Cuba, as well as exemplar populations in Belize and Florida (USA), and sequenced three regions of the mitochondrial genome (D-loop, cytochrome b, cytochrome oxidase I; 3,626 base pair long dataset) that overlapped with published data previously collected from Colombia, Jamaica, and the Cayman Islands. Phylogenetic analyses of these data revealed two, paraphyletic lineages ofC. acutus. One lineage, found in the continental Americas, is the sister taxon toC. intermedius, while the Greater Antillean lineage is most closely related toC. rhombifer. In addition to the paraphyly of the twoC. acutuslineages, we recovered a 5.4% estimate of Tamura-Nei genetic divergence between the Antillean and continental clades. The reconstructed paraphyly, distinct phylogenetic affinities and high genetic divergence between Antillean and continentalC. acutuspopulations are consistent with interspecific differentiation within the genus and suggest that the current taxon recognized asC. acutusis more likely a complex of cryptic species warranting a reassessment of current taxonomy. Moreover, the inclusion, for the first time, of samples from the western population of the American crocodile in Cuba revealed evidence for continental mtDNA haplotypes in the Antilles, suggesting this area may constitute a transition zone between distinct lineages ofC. acutus. Further study using nuclear character data is warranted to more fully characterize this cryptic diversity, resolve taxonomic uncertainty, and inform conservation planning in this system.
Electronic ISSN:
2167-8359
Topics:
Biology
,
Medicine
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