Latest news with #HansLarsson
Time of India
11-05-2025
- Science
- Time of India
Scientists discover new crocodiles on Mexican islands that remained hidden for centuries
Biodiversity is constantly evolving, and as a result, nature surprises us with what is kept hidden in plain sight. While some of the species are becoming extinct and endangered, the discovery of new species not only gives a new ray of hope, but also tells us how much we still have to learn and protect. Tired of too many ads? go ad free now Remote and ecologically rich areas like islands and coastal habitats often house unique species, but they're also among the most vulnerable to human development and environmental change. In this delicate balance between discovery and destruction, science plays a crucial role in identifying species before they vanish, possibly unnoticed. Genetic analysis and modern fieldwork are helping scientists revisit long-held assumptions, bringing to light some unexpected biodiversity. The more we discover, the easier it becomes, as each ecosystem holds details that deserve attention, research, and protection. A recent discovery is a perfect example of the same Scientists have identified two new species of crocodiles living in isolated parts of Mexico, one on the island of Cozumel and the other on the coral atoll of Banco Chinchorro, both situated off the Yucatán Peninsula. This is changing the assumptions, what scientists thought they knew about the American crocodile, which was believed to be a single, widespread species. According to Biology Professor Hans Larsson, the lead investigator of the study, the discovery came after the team analyzed genetic samples from these crocodile populations and compared them to others across the Caribbean, Central America, and Mexico's Pacific coast. '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'. Tired of too many ads? go ad free now Small populations at risk despite stability The two newly identified crocodile species remain unnamed but are genetically distinct, with fewer than 1,000 breeding individuals in each isolated population. While both groups appear stable, their limited numbers and confinement to small habitats make them especially vulnerable. '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,' Larsson added. A wake-up call for conservation The discovery is also a race against time to catalog biodiversity before it's lost. 'Biodiversity is disappearing faster than we can discover what we're losing,' said Larsson. With coastal development and habitat degradation threatening crocodile populations across the globe, this find serves as both a scientific milestone and a conservation alarm bell.
Newsweek
08-05-2025
- Science
- Newsweek
Biologists Reveal Two New Crocodile Species: 'Totally Unexpected'
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. The "totally unexpected" discovery of two new crocodile species off Mexico's Yucatán Peninsula is forcing scientists to reconsider long-held assumptions about the American crocodile—and raising alarms about the fragility of these newly identified populations. "Most species of crocodiles are already endangered, and rapid shoreline development threatens nearly every population," paper author and biologist Hans Larsson of McGill University said in a statement. "Our research aimed to uncover the true diversity of crocodiles on these isolated islands." Working in collaboration with Mexican researchers, Larsson and his team at McGill, identified the new species on the island of Cozumel and the Banco Chinchorro atoll. These isolated groups were long believed to be local populations of the widespread American crocodile, which ranges from Baja California to Venezuela and throughout the Caribbean. A close up image of an American crocodile swimming underwater in an unknown location. A close up image of an American crocodile swimming underwater in an unknown location. Getty Images After sequencing their DNA and comparing their physical features, the researchers concluded that the Cozumel and Banco Chinchorro crocodiles were not simply geographic variants, but genetically distinct species. "These results were totally unexpected," said José Avila-Cervantes, the study's lead author and a former graduate student in Larsson's lab, in a statement. "We assumed [the American crocodile] 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." The findings, based on DNA sequencing and anatomical analysis, challenge previous taxonomies and highlight how little is still known about the biodiversity of remote tropical ecosystems. The study was made possible by a field effort involving the capture and safe release of crocodiles, during which blood and scale samples were collected for genetic analysis. At McGill, Avila-Cervantes performed the genomic sequencing that ultimately revealed big differences between the island populations and mainland counterparts. Additional research on skull morphology was conducted by fellow graduate student Hoai-Nam Bui, further cementing the conclusion that the reptiles represent distinct evolutionary lineages. Although both newly discovered species appear to be stable, their populations are small, with each consisting of fewer than 1,000 breeding individuals. Their restricted habitats and low numbers make them especially vulnerable to environmental disturbances, habitat loss, and the effects of climate change. The discovery underscores the importance of localized conservation efforts, especially in areas that are often overlooked. The scientists are now calling for the crocodiles to be formally recognized as distinct species—a move that could unlock targeted protection in Mexico and internationally. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about crocodiles? Let us know via science@ Reference Avila-Cervantes, J., Charruau, P., Cedeño-Vázquez, J. R., Bui, H.-N., Venegas-Anaya, M., Vargas, M., López-Luna, M. A., González-Cortés, H., Macías-Díaz, D. A., Pérez-Flores, J. S., Barrios-Quiroz, G., Salazar, J. M., McMillan, W. O., & Larsson, H. C. E. (2025). Novel island species elucidate a species complex of Neotropical crocodiles. Molecular Phylogenetics and Evolution, 207.
India Today
08-05-2025
- Science
- India Today
Two new crocodile species discovered. They are different from others
Scientists are stunned to discover two previously unknown species of crocodiles living on the island of Cozumel and the other on the atoll of Banco Chinchorro, both off the Yucatan two new species are yet to be officially discovery challenges previous assumptions about the American crocodile and highlights the urgent need for conservation efforts, the researchers say that even as the population of the species is stable, it's still just a The team analysed the genetic sequences of crocodile populations from Cozumel and Banco Chinchorro and compared them to sequences of crocodiles across the Caribbean, Central America and Mexico's Pacific coast. The newly identified species live in small, isolated populations. (Photo: Getty) They discovered striking levels of genetic differentiation that led the researchers to conclude that these populations were not simply variants of Crocodylus acutus. "Biodiversity is disappearing faster than we can discover what we're losing. 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," Biology Professor Hans Larsson, the principal investigator added that these results were unexpected. "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," Larsson said. The newly identified species live in small, isolated populations, each numbering fewer than 1,000 breeding individuals. While both populations appear stable, their limited numbers and habitat restrictions make them vulnerable."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," Larsson said.
Yahoo
05-05-2025
- Science
- Yahoo
Scientists Found 2 New Crocodile Species Hiding in Plain Sight
Scientists know of four New World crocodile species, but a new study highlights potential fifth and sixth additions to the reptilian family. The two new crocodile species are each endemic to an island off the coast of the Yucatán—the tourist hotspot Cozumel and the atoll Banco Chinchorro. Although stable, the populations are small and are immensely vulnerable to habitat destruction. Of the estimated 8.7 million animal species on Earth, only 1.2 million of them have been officially described, with around 18,000 new species being discovered every year. Many of those are new kinds of jumping spiders, worms, insects, and other wriggling arthropods—the most abundant phylum in the animal kingdom. Huge reptiles don't typically make the list. However, a team of scientists from Canada, Mexico, and Panama claims they've discovered two previously unknown crocodile species off the Yucatán coast in a new study. With the four known species of New World crocodiles—the American, Morelet's, Cuban, and Orinoco—the addition of these two crocodile species discovered on Cozumel and the atoll Banco Chinchorro brings that number up to six. The details of these new species can be found in a new article published in the journal Molecular Phylogenetics and Evolution. 'Biodiversity is disappearing faster than we can discover what we're losing,' McGill biologist Hans Larsson, the senior author of the study, said in a press statement. '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.' One of the oldest-living species of reptile on Earth—sharing (along with birds) some of its genetic lineage with the long-extinct dinosaur—crocodiles migrated to the Americas roughly seven million years ago during the tail end of the Miocene epoch. It's likely that a descendent of New World crocodiles, Crocodylus checchiai, traversed the Atlantic aided in part by westward ocean currents. Although well-known for its perplexingly slow rate of evolution, the crocodile eventually diversified into the four—now six—species we know today in the Americas. The discovery of these new crocs was completely unexpected, according to the study's lead author José Avila-Cervantes. Avila-Cervantes and his team compared the genetic sequences of the crocodile populations found on Cozumel and Banco Chinchorro to other known populations of New World crocodiles, and found enough genetic differentiation to necessitate a new species distinction—not just a variant of the American crocodile, the most widespread of the New World crocodiles. Scientific names have yet to be assigned to these new species, though a hat-tip to their respective island habitats seems like a good bet. Although it's always thrilling to discover a new species—especially one as large as these crocs—the study also adds a dash of concern. Although both populations are stable, they're small, in both ecosystem size and breeding population. The study estimates that each species contain fewer than 1,000 breeding individuals. 'Now that we recognize these crocodiles as distinct species, it's crucial to protect their habitats,' Larsson said in a press statement. 'Limiting land development and implementing careful conservation strategies on Cozumel and Banco Chinchorro will be key to ensuring their survival.' That could prove difficult, as both islands are popular tourist destinations. Cozumel has already seen more than 1.5 million cruise ship tourists in the first three months of 2025, which puts a strain not only on endemic species like crocodiles, but on natural wonders like the island's coral reef system. If the Cozumel and Banco Chinchorro crocodiles have any hope of survival, it'll be because the people of those islands recognize their undeniable worth to the surrounding ecosystem—the natural resource that brings millions flocking to these islands in the first place. You Might Also Like Can Apple Cider Vinegar Lead to Weight Loss? Bobbi Brown Shares Her Top Face-Transforming Makeup Tips for Women Over 50
Express Tribune
02-05-2025
- Science
- Express Tribune
Two new crocodile species discovered, scientists say
Listen to article Scientists have identified two previously unknown crocodile species off Mexico's Yucatán Peninsula, both of which may already be at risk of extinction due to small population sizes and habitat pressures. The new species were found on Cozumel Island and Banco Chinchorro, a coral atoll, and are genetically distinct from the American crocodile (Crocodylus acutus), according to a study published in the journal Molecular Phylogenetics and Evolution. The discovery brings the total number of known New World crocodile species to six. Until now, scientists recognised only the American, Morelet's, Cuban, and Orinoco crocodiles in the region. Researchers from Canada's McGill University, along with partners in Mexico and Panama, conducted genetic and anatomical analyses that revealed enough variation to classify the Cozumel and Banco Chinchorro populations as separate species. 'These results were totally unexpected,' said lead author José Avila-Cervantes. 'We assumed Crocodylus acutus was a single species ranging from Baja California to Venezuela and across the Caribbean.' The research involved collecting DNA and skull measurements from crocodiles in both locations. Notable differences included skull shape, with Banco Chinchorro crocodiles displaying longer and broader snouts. The study estimates that each new species has fewer than 1,000 breeding individuals, and effective population sizes may be as low as 500. While current numbers appear stable, scientists warned that limited habitat and increasing tourism-related development could pose serious risks. 'Biodiversity is disappearing faster than we can discover what we're losing,' said senior author Hans Larsson of McGill. 'Most crocodile species are already endangered. Protecting these habitats is critical.' Cozumel, a major cruise destination, received over 1.5 million visitors in the first three months of 2025 alone. Banco Chinchorro, part of the Mesoamerican Barrier Reef System, is also under ecological strain. The researchers urged governments and conservation groups to implement stricter land-use policies and establish habitat protections to preserve the newly identified species. Although the reptiles are yet to be formally named, researchers hinted that references to their geographic isolation—such as Crocodylus cozumelus or chinchorri—may be used in their taxonomic classification. The study highlights how natural barriers such as ocean currents in the Yucatán region have helped shape biodiversity by isolating species and allowing unique evolution to occur. 'These crocodiles are evolutionary survivors,' said Larsson. 'Now that we know they exist, we must ensure they don't disappear before they are even named.'
