A flat-headed dinosaur lived on an island of dwarf creatures
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A previously unknown dinosaur with an extremely flat head lived about 70 million years ago on an island inhabited by dwarf prehistoric creatures.
Discovered in the area of today’s western Romania, Transylvanosaurus platycephalus (flathead reptile from Transylvania) was 2 meters (6 feet) long – a relatively small size for a dinosaur, according to a new study. The bones of his skull were unearthed in 2007 in the Haţeg basin riverbed.
During the Cretaceous period, this region of Romania was a tropical archipelago. Dinosaurs lived there smaller than their relatives elsewhere; paleontologists think that these dinosaurs were an example of what biologists call “island rule,” where large animals isolated on islands become dwarfed or stunted over time, and small animals become larger.
Sauropods, the largest species of dinosaur that ever lived, reached an average height of just under 6 meters (almost 20 feet) in the archipelago, for example, compared with the 15 to 20 meters (49.2 to 65.6 feet) typical of this group .
However, the mechanism leading to such changes is not fully understood, but could be related to a lack of resources.
Dinosaur bones could survive for tens of millions of years because they were protected by the sediments of the ancient river bed.
“If the dinosaur had died and simply lay on the ground instead of being partially buried, weather and scavengers would have quickly destroyed all of its bones and we would never have known about it,” study co-author Felix Augustin, a paleontologist and Ph.D. student at the University of Tübingen in Germany, according to a press release.
None of the bones the researchers discovered it was more than 12 centimeters (about 5 inches) long, but they revealed a remarkable amount of detail about a small, plant-eating dino that would have walked on two legs and had a powerful, thick tail. It was possible to see the contours of the Transylvanianosaurus brain, the research team said.
“We were able to see the impressions, and thus the proportions, of different parts of the brain—specifically, the olfactory bulbs (the part of the brain responsible for the sense of smell) and the cerebrum, which serves several different functions from sensory processing to memory,” Augustin said via email. .
“The next step would be to compare the proportions of the brain and eye with other related species, as this could provide information about which senses were important to Transylvanianosaurus,” he added.
Haţeg Basin was the hotbed of dinosaur discoveries. Ten species of dinosaurs have already been identified during excavations in the region, and the first dinosaur was discovered in 1900. Transylvanosaurus platycephalus is the first new species of dinosaur to be discovered there in 10 years after a small carnivore and a long-necked herbivore were found in 2010, Augustin said.
Transylvanosaurus 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 far wider than other Rhabdodontidae species, the study says.
Exactly how Transylvanianosaurus ended up in the eastern part of the European archipelago remains unclear.
Researchers believe that this type of dinosaur may have originated in present-day France, where fossils of its closest relatives have been found, and somehow reached the region – perhaps by swimming, or by fluctuations in sea level or tectonic processes that created a land bridge.
“They had powerful legs and a powerful tail,” Augustine said of Transylvanianosaurus. “Most species, especially reptiles, can swim from birth.”
Another possibility is that different lineages of rhabdodontid species evolved in parallel in the East and West Europe.
Regardless of its geographic origin, the newly discovered species helps disprove assumptions that there was little diversity of dinosaurs and other fauna in the Late Cretaceous period, the researchers said. Apart from 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 every land animal on this island was quite small,” Augustin said via email. “The exception was the pterosaurs, some of which reached gigantic body sizes – probably because they could fly and were therefore not as severely affected by the island’s limited resources.”
The research was published on November 23 in Journal of Vertebrate Paleontology.
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