The discovery of the first juvenile dromaeosaurid lower jaw bone on the North Slope of Alaska supports a growing theory that some dinosaurs did not migrate with the seasons but were year-round residents, according to new research by SMU paleontologist Anthony Fiorillo. The findings are based on a “rare” piece of dinosaur jawbone thought to belong to a juvenile dromaeosaurid dinosaur, closely related to birds.
The research published in PLOS ONE said that these dinosaurs "lived all over the world", their bones are fairly delicate and "rarely preserve well in the fossil record", thus hampering researchers' efforts to study how they moved between continents.
"This is the first physical evidence that 70 million years ago, some dromaeosaurid nested in the area...To withstand the rigors of migration, modern caribou need to be at least 80 percent of their adult length. Grown dromaeosaurids ranged from 6 to 9 feet. This baby would have been the size of a small puppy, much too young to migrate," paleontologist Anthony Fiorillo said.
According to phys.org, the bone fragment belonged to a "juvenile" dinosaur from the "dromaeosaurid" family of predatory dinosaurs "closely related to birds", some of whose better-known members include Velociraptors, a breed popularized by the movie "Jurassic Park".
Given its identification & juvenile ontogenetic stage we argue that this fossil is evidence of perennial polar habits in these predatory dinosaurs with broader implication that they were probably all-year-long residents of these high latitudes & not seasonal migratory animals 2/4 pic.twitter.com/Cg0KSQEv04— Alessandro Chiarenza (@AAlechiarenza) July 8, 2020
"If juveniles from these dinosaurs are being found, it means that these animals had to spend a great deal of time mating and nesting in these sites," paleontologist Anthony Fiorillo, chief curator of the Perot Museum of Nature and Science and co-author of the study, was quoted as saying by CNN.
The 14mm long fossil, which was found near the Arctic Ocean, is preserved at the Prince Creek Formation of northern Alaska, which hosts the world’s largest collection of polar dinosaur fossils. It is the first known non-dental dromaeosaurid fossil from the Arctic.