Pseudozoosia Archosaurians are a group of reptiles defined as all species more closely related to crocodiles than to birds. All living representatives of the Pseudozoa are members Crocodile, a group of semi-aquatic ambush predators found predominantly in freshwater habitats of the tropics. There are fewer than 30 species of crocodiles, and more than 700 pseudozoodian species are known from their 250-million-year-old fossil record. In new research, scientists at the University of York and elsewhere have mapped the family tree of Pseudozoonia. They compared this with data from the fossil record to understand why there are so few species of crocodiles.
Life restructuring Poposaurus; This crocodile was about 4 m (13 ft) long and lived alongside the dinosaurs between 237 and 201.3 million years ago. Image credit: Jack Fang.
„Crocodiles and birds share their heritage with archosaurs, and together with pterosaurs they form a group known as archosaurs, or 'ruling reptiles,’ dating back to the early Triassic era,” said University of York researcher Katie Davies and colleagues.
„Pseudosuchia is a group of archosaurian reptiles defined as all species more closely related to crocodiles than to birds.”
For their study, the authors created a large phylogeny, like a family tree, for all crocodilians and their extinct relatives, allowing them to map how many new species are emerging and how many are becoming extinct.
They then combined this with data on past climate change, particularly in temperature and sea level, to assess whether the emergence and extinction of species is linked to climate change.
The researchers also looked at whether interactions between species, such as competition, might play a role, so they calculated estimates of the number of species at any given time and compared them against new species and extinctions, using a type of mathematics called information theory.
This allowed the researchers to develop an estimate of whether climate change and species interactions have a direct impact on whether new species develop or become extinct.
They found that climate change and competition with other species have shaped the diversity of modern-day crocodilians and their extinct relatives, but the findings reveal ecology — whether species live in the ocean, freshwater or on land — played an unexpectedly important role. Survival.
The published study found that as global temperatures rose, the number of crocodiles’ marine life and land-based relatives increased, while competition for resources increased, perhaps bringing with it sharks, marine reptiles or dinosaurs. their destruction.
In contrast, crocodiles’ freshwater relatives were not affected by temperature but were threatened with extinction by rising sea levels.
With seven species classified as is in critical condition Four more species have been identified VulnerableThe findings provide important insights into conservation efforts for crocodiles and other species as the climate continues to change.
„The fossil record is a rich source of valuable information that allows us to look back through time at how and why species evolved and, importantly, what caused their extinction,” said Dr Davies.
„By examining this record and mapping it against the crocodile family tree, our research reveals how important it is to think about ecology when we try to predict how species will respond to today’s climate change.”
„With a million species of plants and animals dangerously close to extinction, understanding the key factors behind why species are disappearing has never been more important.”
„For crocodiles, many species inhabit low-lying areas, meaning rising sea levels associated with global warming could irreversibly alter the habitats they depend on.”
„Crocodiles and their extinct relatives provide unique insights into climate change and its impact on biodiversity in the past, present and future.”
„Our findings improve our understanding of what factors have shaped and continue to shape Earth.”
The study Published in the magazine Natural Ecology & Evolution.
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ART Payne and many others. 250 million years of both abiotic and biotic drivers of diversification and extinction drive diversity in crocodilian-line archosaurs. Nat Ecole Evol, published online December 4, 2023; doi: 10.1038/s41559-023-02244-0