Crocodiles immigrated to the Neotropics from Africa approximately 5 million years ago and diversified into the four living species recognized today.<\/p>\n
The American crocodile (Crocodylus acutus) inhabits a wide variety of environments from hypersaline to freshwater localities on the mainland, islands, cays, and coral atolls along the Neotropical Pacific and Caribbean coasts and is sympatric with populations of the three other species.<\/p>\n
Although the Morelet\u2019s crocodile (Crocodylus moreletii) is considered a species of Least Concern, the American crocodile is listed as vulnerable and the remaining two species are Critically Endangered on the International Union for Conservation of Nature\u2019s Red List.<\/p>\n
\u201cBiodiversity is disappearing faster than we can discover what we\u2019re losing,\u201d said Professor Hans Larsson, a researcher at McGill University.<\/p>\n
\u201cMost species of crocodiles are already endangered, and rapid shoreline development threatens nearly every population.\u201d<\/p>\n
\u201cOur research aimed to uncover the true diversity of crocodiles on these isolated islands.\u201d<\/p>\n
Professor Larsson and his team analyzed the genetic sequences of crocodile populations from Cozumel and Banco Chinchorro.<\/p>\n
Comparing these sequences to those of crocodiles across the Caribbean, Central America and Mexico\u2019s Pacific coast, they found striking levels of genetic differentiation, leading the researchers to conclude that these populations were not simply variants of the American crocodile.<\/p>\n
\u201cThese results were totally unexpected,\u201d said Dr. Jos\u00e9 Avila-Cervantes, also of McGill University.<\/p>\n
\u201cWe assumed Crocodylus acutus was a single species ranging from Baja California to Venezuela and across the Caribbean.\u201d<\/p>\n
\u201cOur study is the first to extensively explore genomic and anatomical variation in these animals.\u201d<\/p>\n
The two new species live in small, isolated populations, each numbering fewer than 1,000 breeding individuals.<\/p>\n
While both populations appear stable, their limited numbers and habitat restrictions make them vulnerable.<\/p>\n
\u201cThe rapid loss of biodiversity can only be slowed if we know what species are most at risk,\u201d Professor Larsson said.<\/p>\n
\u201cNow that we recognize these crocodiles as distinct species, it\u2019s crucial to protect their habitats.\u201d<\/p>\n
\u201cLimiting land development and implementing careful conservation strategies on Cozumel and Banco Chinchorro will be key to ensuring their survival.\u201d<\/p>\n
The team\u2019s paper was published in the journal Molecular Phylogenetics and Evolution.<\/p>\n
Jose Avila-Cervantes et al. 2025. Novel island species elucidate a species complex of Neotropical crocodiles. Molecular Phylogenetics and Evolution 207: 108341; doi: 10.1016\/j.ympev.2025.108341<\/p>\n