New research reveals that prehistoric reptiles survived extreme climate conditions and migrated thousands of miles – and that may be why they became dinosaurs
New research suggests that the ancestors of dinosaurs and crocodiles during the Triassic period were able to migrate through vast areas of the ancient Earth that were previously considered uninhabitable.
In a study published in the journal Nature Ecology and EvolutionScientists from the University of Birmingham and the University of Bristol have used a new geographical method to examine how ancient reptiles called archosauromorphs spread around the world after the end-Permian mass extinction – one of the most severe climate events in Earth's history.
Archaeozoomorphs survived the tropical heat
The first archosauromorphs, which resembled modern reptiles and were much smaller than the dinosaurs that came after them, were previously thought to have survived only in limited areas of the world.
Many paleontologists believed that the extreme heat in the tropics created a "dead zone" in the Early Triassic—an area uninhabitable for these animals.
Reconstructing ancient migration routes
Using a new modeling technique that combined landscape reconstructions with evolutionary trees, researchers have uncovered clues about how these reptiles migrated across the planet during the Triassic period, following an extinction event that wiped out more than half of all land animals and 81% of marine species.
The archosauromorphs that survived the extinction became key players in the ecosystems of the Triassic period, a process that eventually led to the emergence of dinosaurs. Researchers now believe that their success was due, in part, to their ability to traverse distances of up to 10,000 miles (about 16,000 km) through the tropical "dead zone" to reach new ecosystems.
Life survived the worst climate disaster
Dr Joseph Flannery-Sutherland from the University of Birmingham, co-author of the paper, said:
"In the midst of the most severe climate event in Earth's history, in which more species than ever before became extinct, life still survived. We know that archaeozoomorphs managed to emerge from this event and during the Triassic period became leading players in the evolution of life on Earth."
"The gaps in their fossil record are starting to tell us about what we haven't seen. Using the modeling system we developed, we were able to build a picture of what happened to archaeozoomorphs in those gaps, and how they migrated across the ancient world. We called our method TARDIS – because it looks at trajectories that are directed through space-time."
"Our findings suggest that these reptiles were much more resistant to the extreme conditions of the tropical 'dead zone' of Pangaea, and were able to survive the hellish conditions to reach the other side of the world. This ability may have given them a crucial advantage that contributed to their prosperity during the Triassic period."
Professor Michael Benton from the University of Bristol, senior author of the paper, added: "The evolution of life has often been influenced by the environment, but it is difficult to combine our limited and uncertain knowledge of the ancient landscape with our partial understanding of the ecology of extinct creatures. By combining fossils with reconstructed maps and evolutionary trees, we have been able to overcome this challenge."
More of the topic in Hayadan:
