For the first time ever, scientists have used "network theory" to create a visual to the movement of dinosaurs during the Mesozoic Era, revealing an unusual journey from Europe. The findings also support previous studies that suggested that dinosaurs continued to migrate around the world after Pangaea split into individual land masses separated by ocean.
"We presume that temporary land bridges formed due to changes in sea levels, temporarily reconnecting the continents," said Alex Dunhill, a researcher from the University of Leeds and first author on the study. "Such massive structures - spanning, for example, from Indo-Madagascar to Australia - may be hard to imagine. But over the timescales that we are talking about, which is in the order of tens of millions of years, it is perfectly feasible that plate tectonic activity gave rise to the right conditions for such land bridges to form."
The team took advantage of the Paleobiology Database, which contains every documented and available dinosaur fossil, and cross-mapped fossil records from the same families but different continents over various periods of time. The end result is a visual that shows how the dinosaurs migrated.
In order to control for the fact that some parts of the world have more robust fossil records than others, the team compensated by applying a filter to the database records in order to only count the first instance of a dinosaur family connection between two continents.
Not only do the findings support the continued migration of dinosaurs after continental splitting, they reveal that all of the connections between Europe and other continents during the Early Cretaceous period were outward, meaning no new dinosaur families were coming into Europe while others were leaving.
"This is a curious result that has no concrete explanation," Dunhill said. "It might be a real migratory pattern or it may be an artifact of the incomplete and sporadic nature of the dinosaur fossil record."
Although network theory is typically used in computer science disciplines to analyze internet data, it has recently made its way into the realm of biology research.
"Network theory has been studied in physics for a number of years, however it is finally permeating into other disciplines," said James Sciberras of the University of Bath and co-author of the study. "This idea that most things can, and should, be considered in the context of the whole system will lead to some exciting new findings in a wide range of fields."
The findings were published in the April 25 issue of the Journal of Biogeography.
