Crocodiles are masters of survival. These ancient reptiles have been around for about 90 million years, outlasting dinosaurs and enduring multiple extinction events. Around 5 million years ago, they crossed from Africa to the Americas and evolved into the four species known in the region today.
Scientists have long known that the so-called "neotropical" crocodiles are widespread, living in a mix of coastal zones, remote inland areas, and scattered islands. But human activity has severely impacted many of their habitats, pushing some populations to the brink of extinction.
Now, researchers from McGill University, working with Mexican conservation institutions, have made a groundbreaking discovery: two previously unrecognized crocodile species — one inhabiting Cozumel Island and the other residing on the Banco Chinchorro atoll, both off the coast of the Yucatán Peninsula. This revelation could reshape how conservation efforts are prioritized moving forward.
"Biodiversity is disappearing faster than we can discover what we’re losing," said principal investigator and biology professor Hans Larsson in a news release. "Most species of crocodiles are already endangered, and rapid shoreline development threatens nearly every population. Our research aimed to uncover the true diversity of crocodiles on these isolated islands."
More Crocodile Diversity Than Expected
The research focused on the Yucatán Peninsula, a striking area that forms part of the Mesoamerican Barrier Reef — the largest reef system in the Atlantic. It’s also a region where ocean currents can limit the movement of animals, creating natural barriers that isolate populations and drive genetic change.
With the help of local volunteers, scientists captured crocodiles, took blood and scale samples, and released them back into their native habitats around Cozumel and Banco Chinchorro. By analyzing their DNA and comparing physical features like skull shape, the team found surprising differences from the known American crocodile (Crocodylus acutus). These distinctions suggested they were looking at two entirely new species.
"These results were totally unexpected," said lead author José Avila-Cervantes in a news release. "We assumed Crocodylus acutus was a single species ranging from Baja California to Venezuela and across the Caribbean. Our study is the first to extensively explore genomic and anatomical variation in these animals."
Read More: How Crocodiles Have Survived Over 230 Million Years and Two Mass Extinction Events
Why Conservation Matters
Understanding how different populations are related helps conservationists decide where to focus their efforts. This new discovery could dramatically shift priorities, especially because the two newfound species each have fewer than 1,000 individuals — making them especially vulnerable to changes in their environments.
While current populations appear stable, their limited numbers mean any disturbance — like development or climate shifts — could have serious consequences.
"The rapid loss of biodiversity can only be slowed if we know what species are most at risk," added Larsson. "Now that we recognize these crocodiles as distinct species, it’s crucial to protect their habitats. Limiting land development and implementing careful conservation strategies on Cozumel and Banco Chinchorro will be key to ensuring their survival."
Naming the New Crocodiles
The two crocodile species haven’t been formally named yet. That process requires other experts to verify the discovery by agreeing on how genetically distinct and reproductively isolated these populations are from their closest relatives. Once confirmed, each species will be given a scientific name, usually reflecting a unique trait or honoring someone involved in the research.
Maybe we’ll soon see names like Crocodylus larssoni, cervanti, cozumelus, or chinchorri join the roster of neotropical crocodile species.
Read More: These Extinct Giant Crocs May Have Hunted Out Ancient Ancestors
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Molecular Phylogenetics and Evolution: Novel island species elucidate a species complex of Neotropical crocodiles
University of Rochester: What makes a species different?
Having worked as a biomedical research assistant in labs across three countries, Jenny excels at translating complex scientific concepts – ranging from medical breakthroughs and pharmacological discoveries to the latest in nutrition – into engaging, accessible content. Her interests extend to topics such as human evolution, psychology, and quirky animal stories. When she’s not immersed in a popular science book, you’ll find her catching waves or cruising around Vancouver Island on her longboard.
