A team of scientists at the University of York has conducted a comprehensive study to trace the evolutionary trajectory of crocodiles. This research highlights the influences of climate shifts, interspecies competition, and ecological variables on the crocodiles’ present-day limited diversity. These insights are pivotal for conservation strategies. Acknowledgement: Jagged Fang Designs.
The team specifically focused on constructing a phylogenetic map for crocodiles and their extinct kin, aiming to elucidate the reasons behind the limited variety of extant crocodile species.
Led by the University of York, the researchers meticulously mapped the phylogenetic tree of these formidable ambush predators and their extinct kin, the Pseudosuchia. By integrating this map with fossil data, they aimed to understand the scarcity of living crocodile species compared to the 11,000 bird species, their closest living relatives.
The study found that changes in climate and competition with other species have been crucial in shaping the diversity of present-day crocodiles and their extinct relatives. However, a surprising revelation was the significant role of ecology – the environment in which species thrive (sea, freshwater, land) – in their survival.
Published in Nature Ecology & Evolution on December 4, the research reveals that rising global temperatures increased the diversity of sea-dwelling and land-based crocodilian relatives, while competition for resources, potentially with sharks, marine reptiles, or dinosaurs, may have led to their extinction. In contrast, crocodiles living in freshwater environments were less affected by temperature changes but more vulnerable to rising sea levels.
The study spotlights Poposaurus, a member of the extinct Poposauroidea group, a four-meter-long crocodilian that lived alongside dinosaurs from 237 to 201.3 million years ago. Credit: Jagged Fang Designs
With seven crocodile species listed as Critically Endangered and four as vulnerable, this research is crucial for the conservation of crocodiles and other species, especially in the context of ongoing climate change.
Dr. Katie Davis, the study’s senior author from the University of York’s Department of Biology, emphasized the value of the fossil record in understanding species origination and extinction. She noted that this research underscores the importance of considering ecology in predicting species’ responses to current climate changes.
She highlighted the urgency of understanding the factors behind species extinction, especially as a million plant and animal species face extinction. The study points out that many crocodile species inhabit low-lying areas, which are at risk due to rising sea levels and global warming, potentially causing irreversible habitat changes.
The study also touches upon the shared lineage of crocodiles, birds, and dinosaurs, along with pterosaurs, under the archosaur group (“ruling reptiles”), dating back to the Early Triassic. The Pseudosuchia, a group of archosaurian reptiles, is defined by their closer relation to crocodiles than to birds.
The researchers constructed an extensive phylogeny for all crocodiles and their extinct relatives. This family tree helped in understanding the rates of new species formation and extinction. They coupled this data with historical climate change information, focusing on temperature and sea level changes, to assess the link between species emergence/extinction and climate change.
The team also investigated interspecies interactions, like competition, using Information Theory mathematics. This approach enabled them to estimate the direct impact of climate change and species interactions on species emergence and extinction.
Dr. Davis concluded by emphasizing the unique insights provided by crocodiles and their extinct relatives into the effects of climate change on biodiversity across different eras, enhancing our understanding of the forces shaping life on Earth.
Reference: “Decoupling speciation and extinction reveals both abiotic and biotic drivers shaped 250 million years of diversity in crocodile-line archosaurs” 4 December 2023, Nature Ecology & Evolution.
DOI: 10.1038/s41559-023-02244-0
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Frequently Asked Questions (FAQs) about Crocodile Evolution Study
What does the University of York study reveal about crocodile evolution?
The study by the University of York researchers maps the evolutionary history of crocodiles, showing how climate change, competition, and ecological factors have influenced their current limited diversity. It provides crucial insights for conservation efforts, highlighting the importance of ecology in the survival of crocodile species.
How did climate change and competition affect crocodile diversity?
The research found that climate change and competition with other species significantly shaped the diversity of modern-day crocodiles and their extinct relatives. Rising global temperatures influenced the diversity of sea-dwelling and land-based crocodilian relatives, while competition for resources, possibly with sharks, marine reptiles, or dinosaurs, likely led to their extinction.
What role does ecology play in crocodile evolution according to the study?
Ecology, or the environment in which species live (sea, freshwater, or land), played a key role in the survival of crocodile species. The study reveals that crocodiles in freshwater environments were less affected by temperature changes but more vulnerable to rising sea levels.
What are the conservation implications of the study on crocodiles?
With seven crocodile species classified as Critically Endangered and four as vulnerable, the study provides important insights for the conservation of these species. It underscores the need to consider ecological factors and the impact of climate change, especially in low-lying habitats, for effective conservation strategies.
How does the study contribute to our understanding of species extinction and climate change?
The research offers insights into how species, particularly crocodiles, have responded to past climate changes and ecological pressures. It emphasizes the importance of understanding these factors to predict and mitigate the impacts of current and future climate change on biodiversity, especially for species close to extinction.
More about Crocodile Evolution Study
- Nature Ecology & Evolution Study
- University of York Biology Department
- Crocodile Conservation Efforts
- Climate Change and Biodiversity Impact
- Archosaur Evolution Research
4 comments
gotta say, reading this makes me think more about how we need to protect these animals, especially with the climate changing so fast. conservation is key, folks
Surprised to read how ecology plays such a big part in crocodile evolution. Thought it was all about climate, but it’s way more complex. great article!
Wow, this study really puts into perspective how climate change affects species like crocs. Didn’t realize how competition played a role too, pretty interesting stuff
its amazing to see how much we can learn from fossils, like the whole history of these incredible animals laid out from their past to now