Dinosaur that lived on island of dwarf creatures had a flattened head

A previously unknown dinosaur with an unusually flat head lived around 70 million years ago on an island that was home to prehistoric dwarf creatures.

Discovered in what is now western Romania, Transylvanosaurus platycephalus (a flat-headed reptile from Transylvania) was two meters long — a relatively small size for a dinosaur, according to a new study.

His skull bones were unearthed in 2007 in a riverbed in the Haţeg Basin.

In the Cretaceous period, this region of Romania was a tropical archipelago.

The dinosaurs that lived there were smaller than their relatives elsewhere; paleontologists think these dinosaurs were an example of what biologists call “island rule,” where large animals isolated on islands become dwarfed or stunted in their growth over time and small animals become larger.

Sauropods, the largest type of dinosaur that ever lived, reached average heights of a paltry 6 meters in the archipelago, for example, compared to the typical 15 to 20 meters for the group.

However, the mechanism that gives rise to these changes is not fully understood, but it may be linked to resource scarcity.

Dinosaur bones managed to survive for tens of millions of years because sediment from an ancient riverbed protected them.

“If the dinosaur had died and simply stayed in the ground instead of being partially buried, the weather and scavengers would soon have destroyed all of its bones and we would never have found out about it,” said Felix Augustin, study co-author, paleontologist and student of doctorate at the University of Tübingen, Germany, said in a press release.

None of the bones the researchers uncovered were longer than 12 centimeters, but they revealed a remarkable amount of detail about the small plant-eating dinosaur that walked on two legs and had a thick, powerful tail.

It was possible to discern the contours of the Transylvanosaurus brain, the research team said.

“We were able to see the impressions, and therefore the proportions, of different sections of the brain – more specifically, the olfactory bulbs (the section of the brain responsible for the sense of smell) and the brain, which serves many different functions, from sensory processing to memory,” Augustin said via email.

“The next step would be to compare brain and eye proportions with other related species, as this may provide insight into which senses were important for Transylvanosaurus,” he added.

The Haţeg Basin has been a hotbed of dinosaur discoveries. Ten species of dinosaurs have been identified during excavations in the region, with the first dinosaur discovered in 1900.

Transylvanosaurus platycephalus is the first new dinosaur species to be discovered there in 10 years after a small carnivore and long-necked herbivore was found in 2010, Augustin said.

It was a plant eater and part of a family of dinosaurs known as the Rhabdodontidae that were common during the Late Cretaceous period. Its head was much wider than other Rhabdodontidae species, the study said.

Precisely how Transylvanosaurus ended up in the eastern part of what was the European archipelago remains unclear.

Researchers believe this type of dinosaur may have originated in what is now France, where fossils of its closest relatives have been found, and somehow arrived in the region – perhaps by swimming or due to fluctuations in sea level or tectonic processes. who created a bridge earth.

“They had powerful legs and a powerful tail,” Augustin said of Transylvanosaurus. “Most species, reptiles in particular, can swim from birth.”

Another possibility is that several lineages of rhabdodontid species evolved in parallel in Eastern and Western Europe.

Regardless of their geographic origins, the newly discovered species help refute assumptions that there was low diversity of dinosaurs and other fauna at the end of the Creaceous period, the researchers said.

In addition to dwarf dinosaurs, the Haţeg Basin was also home to crocodiles, giant pterosaurs (flying reptiles) and turtles – before the dinosaurs went extinct 66 million years ago.

“Almost all of the land animals on this island were very small,” Augustin said via email. “One exception were pterosaurs, some of which reached gigantic body sizes – the reason for this is likely that they could fly and therefore were not as severely affected by the island’s limited resources.”