Island species from the past were usually stranger and smaller than close relatives on continental landmasses.
Paleontologists have discovered an unusual carnivorous dinosaur that once lived on a European island.
The finding represents the most complete predatory dinosaur skeleton from the middle to Late Cretaceous Europe.
The meat-eating dinosaur likely ate dwarfed herbivorous dinosaurs, previously found near the site.
Transylvania was Count Dracula's mythical home, but in reality, this historical region of Romania during the Late Cretaceous was home to a strange predatory dinosaur, according to paleontologists who studied its fossilized bones.
Named Balour bondoc, meaning "stocky dragon," the meat-eating dinosaur lived from around 72 to 65 million years ago. Its skeleton represents the most complete predatory dinosaur from this time in Europe, which was mostly underwater. Romania was an island then.
Island species from the past were usually stranger and smaller than close relatives on continental landmasses, exemplifying what scientists call the "island effect."
"Animals tend to do strange things on islands, simply because they are allowed to," project leader Zoltán Csiki told Discovery News. "Selective forces and restraints are more relaxed in island environments than within the more competitive continental environments."
Csiki, a University of Bucharest paleontologist, and his team analyzed the dinosaur's fossils, unearthed near Sebes in Alba County, Romania. The findings are reported in the latest issue of the Proceedings of the National Academy of Sciences.
The scientists determined that Balour bondoc has 20 unique features when compared to its nearest relatives. These include two large sickle claws on both feet, presumably used to slash prey. The dinosaur also possessed short, stocky legs and feet with bones fused together, possibly to stabilize limb posture. Its pelvis has enormous muscle attachment areas, indicating the species was adapted for strength over speed.
"Balaur is a new breed of predatory dinosaur very different from anything we have ever known," said co-author Stephen Brusatte, a Columbia University graduate student who is affiliated with the American Museum of Natural History. "Its anatomy shows that it probably hunted in a different way than its less stocky relatives."
The scientists say Balaur bondoc was a dromaeosaur, a type of bird-like carnivore. It was related to dinosaurs such as Velociraptor, which lived at around the same time in other parts of Europe, Asia and North America.
"Compared to Velociraptor, Balaur was probably more of a kickboxer than a sprinter, and it might have been able to take down larger animals than itself as many carnivores do today," Brusatte said.
The prey of this six to seven-foot-long predator might have included tiny duck-billed dinosaurs and dwarf sauropods that were the size of cows. Remains of these herbivores were previously discovered near the site.
It remains a mystery how dinosaurs first migrated to the European island. Csiki thinks the travel might have been possible via land bridges, by animals accidentally rafting across stretches of water, by chance dispersal during sea level drops, or through some other means.
Michael Benton, director of the Palaeobiology and Biodiversity Research Group at the University of Bristol, has also studied Transylvania's dinosaurs.
Benton told Discovery News that the ecosystem there at the time also included "fish, frogs, albanerpetonids (salamander-like amphibians), turtles, crocodilians, pterosaurs, birds, lizards, snakes and mammals."
Given these earlier findings, scientists suspected that bigger meat eaters were present, but no predatory dinosaurs had been located until now.
American Museum of Natural History paleontologist Mark Norell, who worked on the latest PNAS study, concluded: "While we would expect that there were carnivorous animals in these faunas, finding one as unusual as Balaur is thrilling and is testament to the unusual animals found on islands today and in the past."