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A previously unknown dinosaur with a remarkably flattened head lived about 70 million years ago on an island home to dwarf prehistoric animals.
Now discovered in western Romania, Transylvanianosaurus platycephalus (flat-headed reptile from Transylvania) was 2 meters (6 ft) long – a relatively small size for a dinosaur, According to a new study. Its skull bones were found in 2007 at the bottom of a river in the Hageg Basin.
During the Cretaceous period, this area of Romania was a tropical archipelago. Dinosaurs lived there smaller than their relatives elsewhere; Paleontologists think these were dinosaurs An example of what biologists call “island rule,” where large animals isolated on islands become dwarfed or stunted in growth over time, and smaller animals grow larger.
Sauropods, the largest type of dinosaur that ever lived, reached an average height of 6 meters (about 20 feet) in the archipelago, for example, compared to 15 to 20 meters (49.2 to 65.6 feet) typical for the group.
However, the mechanism giving rise to such changes is not fully understood but may be linked to resource scarcity.
Dinosaur bones were able to survive for millions of years because the sediments of an ancient river bed protected them.
“If the dinosaur had died and 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 Félix Augustin, a paleontologist and Ph.D. the student at the University of Tübingen in Germany, according to a news release.
Researchers did not uncover any bones It was longer than 12 centimeters (about 5 inches), but they revealed a remarkable amount of detail about the small plant-eating dino that walked on two legs and had a strong, thick tail. It was possible to outline the brain of Transylvanianosaurus, the research team said.
“We were able to see the impressions, and thus the ratio, of different parts of the brain – more specifically, the olfactory bulb (the part of the brain responsible for the sense of smell) and the cerebrum, which do a variety of tasks from sensory processing. memory,” Augustine said via email.
“The next step will be to compare brain and eye proportions with other related species, as this may provide information about which senses were important for Transylvanianosaurus,” he added.
The Haţeg Basin has been a hotbed for dinosaur discoveries. Ten dinosaur species have already been identified during excavations in the area, with the first dinosaur discovered in 1900. Transylvanianosaurus platycephalus It is the first new dinosaur species discovered there in 10 years since a small carnivore and long-necked plant eater was discovered in 2010, Augustine said.
Transylvanianosaurus was a plant eater and part of a family of dinosaurs known as the Rhabdodontidae. Cretaceous period. Its head was much wider than that of other Rhabdodontidae species, the study said.
It is still unclear how Transylvanianosaurus ended up in the eastern part of the European archipelago.
Researchers believe that this type of dinosaur may have originated in present-day France, where its closest relatives have been found fossilized, and somehow made it to the region – perhaps by swimming, or due to sea-level fluctuations or tectonic processes. Built a land bridge.
“They had strong legs and a strong tail,” Augustine said of Transylvanianosaurus. “Most species, especially reptiles, can swim from birth.”
Another possibility is that different lines of rhabdodontid species evolved in parallel in the east and west Europe.
Regardless of its geographic origin, the newly discovered species helps refute assumptions that dinosaurs and other fauna were less diverse during the late Cretaceous period, the researchers said. Along with dwarf dinosaurs, the Hageg Basin was 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 pretty small,” Augustine said via email. “The one exception was the pterosaurs, some of which reached enormous body sizes—probably because they could fly and thus weren’t so severely affected by the island’s limited resources.”
The study was published on November 23 Journal of Vertebrate Paleontology.
