Pioneering reconstruction of prehistoric landscape reveals first dinosaurs lived on tropical islands

A new study using cutting edge technology has shed surprising light on the ancient habitat where some of the first dinosaurs roamed in the UK around 200 million years ago.

The research, conducted by the University of Bristol, examined hundreds of data old and new, including historical literature vividly describing the landscape as a “landscape of limestone islands like the Florida Everglades” swept by trees. storms powerful enough to “scatter pebbles, roll up fragments of marl, break bones and teeth.” ”

The evidence has been carefully compiled and digitized so that it can be used to generate for the first time a 3D map showing the evolution of a Caribbean-style environment, which has hosted small dinosaurs, lizard-like animals and some of the first mammals.

“No one has ever gathered all of this data before. These tiny dinosaurs and lizard-like animals were often thought to live in a desert landscape, but this provides the first standardized evidence to support the theory that they did live. side by side on flooded tropical islands, ”said Jack Lovegrove, lead author of the study published today in Journal of the Geological Society.

The study gathered all the data on geological succession measured all around Bristol over the past 200 years, from quarries, stretches of road, cliffs and boreholes, and generated a 3D topographic model of the area to show the landscape before the Rhaetian Flood, and over the next 5 million years, with sea level rise.

By the end of the Triassic Period, the UK was close to the equator and enjoyed a warm Mediterranean climate. The sea level was high because a large sea, the Rhaetian Ocean, flooded most of the land. The Atlantic Ocean began to open up between Europe and North America, causing land levels to drop. In the Bristol Channel area, the sea level was 100 meters higher than today.

Elevated areas, such as the Mendip Hills, a ridge across the Clifton Downs in Bristol, and the hills of South Wales weaved through the water, forming an archipelago of 20 to 30 islands. The islands were made of limestone which cracked and cracked with the rain, forming cave systems.

“The process was more complicated than just drawing the old coastlines around the current 100-meter contour line, because as the sea level rose there were all kinds of small-scale faults. says Jack, who studies paleontology and evolution.

The results provided insight into the type of environment inhabited by the Thecodontosaurus, a small dinosaur about the size of a medium-sized, long-tailed dog, also known as the Bristol dinosaur.

Co-author Professor Michael Benton, Professor of Vertebrate Paleontology at the University of Bristol, said: “I was looking forward to doing this work to try and figure out exactly what the ancient Triassic landscape looked like. superior. The thecodontosaurus lived on several of these. islands including the one that crosses the Clifton Downs, and we wanted to understand the world it occupied and why the dinosaurs on the different islands differ. Maybe they couldn’t swim too well. “

“We also wanted to see if these early islanders exhibited any of the effects of island living,” said co-author Dr David Whiteside, research associate at the University of Bristol.

“On the islands today, medium-sized animals are often dwarf because there are fewer resources, and we’ve found that in the case of the Bristol Archipelago. We also found evidence that the smaller islands were occupied by a small number of species, while the larger islands, like Mendip Island, could support many more. “

The study, carried out with the British Geological Survey, demonstrates the level of detail that can be derived from geological information using modern analytical tools. The new map even shows how Mendip Island was flooded step by step, with the sea level rising a few meters every million years, until it was almost completely inundated 100 million years ago. years later, in the Cretaceous.

Co-author Dr Andy Newell, British Geological Survey, said: “It was great working on this project because 3D models of the earth’s crust can help us understand so much about the history of the landscape, and also where to find water resources. In the UK we have this rich resource of historical data from mining and other development activities, and now we have the computational tools to create complex models. but precise. “

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Paper

“ Testing the relationship between marine transgression and evolving island paleogeography using 3D GIS: an example from the Late Triassic of southwest England ” by Lovegrove, J., Newell, AJ, Whiteside, DI, and Benton, MJ in Journal of the Geological Society