Scientists discover possible origin of first ‘warm-blooded’ dinosaurs

A new study by researchers from University College London and the University of Vigo suggests that the ability to regulate body temperature, a property shared by all modern mammals and birds, may have first evolved among some dinosaurs in the early Paleolithic. Jurassic A period approximately 180 million years ago.

A new study by researchers from University College London and the University of Vigo suggests that the ability to regulate body temperature, a characteristic shared by all mammals and birds, may have first evolved in some dinosaurs during the Early Jurassic period, about 180 million years ago.

In the early twentieth^y In the 20th century, dinosaurs were considered slow-moving, cold-blooded animals like modern reptiles, relying on the heat of the sun to regulate their temperature. More recent discoveries indicate that some species of dinosaur were likely able to generate their own body heat but when this adaptation occurred is unknown.

Research methods and results

The new study published in the journal Current biologylooked at the spread of dinosaurs across different climates on land around the world Mesozoic Era (the Age of Dinosaurs, which lasted from 230 to 66 million years ago), based on 1,000 fossils, climate and geographic models of the period, and dinosaur evolutionary trees.

The research team found that two of the three main groups of dinosaurs, theropods (e.g T-Rex And Velociraptor) and ornithischians (including plant-eating relatives Stegosaurus And Triceratops), they moved to cooler climates during the Early Jurassic, suggesting that they may have developed endothermy (the ability to generate heat internally) at this time. In contrast, sauropods, the other major group that includes… Brontosaurus And the Diplodocusare kept in warmer regions of the planet.

Previous research has found traits associated with warm blood among ornithischians and theropods, some of which are known to have had primitive feathers or feathers, which insulated internal heat.

Evolutionary implications

First author Dr Alfio Alessandro Chiarenza, from UCL Earth Sciences, said: “Our analyzes show that different climate preferences emerged among major dinosaur groups around the time of the Jenkins Event 183 million years ago, when intense volcanic activity led to global warming and climate change. the climate”. Extinction of plant populations.

“At this time, many new groups of dinosaurs appeared. The adoption of endothermy, as a result of this environmental crisis, may have enabled theropods and ornithischians to thrive in cold environments, allowing them to be very active and maintain activity over longer periods.” To develop and grow faster and produce more offspring.

Co-author Dr Sara Varela, from the University of Vigo, Spain, said: “Theropods also include birds, and our study suggests that unique avian temperature regulation may have had an origin in this early Jurassic period. Sauropods, on the other hand, that survived in warmer climates grew , reached gigantic size around this time – another possible adaptation due to environmental pressure. Their smaller surface area to volume ratio meant that these larger creatures would lose heat less frequently, allowing them to remain active for longer.

Wider implications of the research

In this paper, the researchers also investigated whether sauropods remained at lower latitudes to eat rich foliage not available in cold polar regions. Instead, they found that sauropods seemed to thrive in arid, savannah-like environments, supporting the idea that their restriction to warmer climates was more related to warming then to cold-blooded physiology. During that period, the polar regions were warmer, with an abundance of plants.

The Jenkins Event occurred after lava and volcanic gases erupted from long fissures in the Earth’s surface, covering large areas of the planet.

Co-author Dr. Juan L. Cantalapiedra, from the National Museum of Natural Sciences, Madrid, Spain: “This research suggests a close link between climate and how dinosaurs evolved. It sheds new light on how birds may have inherited a unique biological trait from their dinosaur ancestors and the different ways in which they adapted.” Dinosaurs with complex and long-term environmental changes.

Reference: “The Early Jurassic Origin of Avian Endothermy and Thermal Physiological Diversity in Dinosaurs” by Alfio Alessandro Chiarenza, Juan L. Cantalapiedra, and Luis A. Jones, Sarah Gamboa, Sofia Galván, and Alexander J. Farnsworth, and Paul J. Varela, May 15, 2024, Current biology.
DOI: 10.1016/j.cub.2024.04.051

The study was funded by the European Research Council, the Royal Society, the Natural Environment Research Council, and the Spanish Ministry of Research.

The study included researchers from the University of California, Los Angeles, the University of Vigo, and… University of Bristoland the National Museum of Natural Sciences in Madrid, and has received funding from the European Research Council, the Spanish Ministry of Research, the Natural Environment Research Council, and the Royal Society.