Scientists have long believed that dinosaurs declined in numbers before the asteroid strike that wiped them out 66 million years ago. However, a new study suggests that this decline may be due to a poor fossil record rather than actual environmental changes.
Researchers analyzed nearly 18 million years of fossil evidence from around 8,000 fossils found in North America and found that dinosaur diversity peaked around 76 million years ago before decreasing until the asteroid strike. However, they couldn’t find any indication of environmental factors that would explain this decline. Instead, they believe that geological conditions during the Maastrichtian age may have hindered fossilization, making it appear as if there were fewer dinosaurs and less diversity.
The study found that Ceratopsians, a group of horned dinosaurs, were the most common due to their preference for plain regions conducive to preservation. Hadrosaurians, or duck-billed dinosaurs, were the least common possibly due to their preference for rivers with reduced sediment deposition.
Lead researcher Chris Dean said, “Dinosaurs weren’t doomed to extinction at the end of the Mesozoic era.” Co-author Alfio Alessandro Chiarenza added, “If it weren’t for that asteroid, they might still share this planet with mammals, lizards, and their surviving descendants: birds.”
The study’s findings have significant implications for our understanding of dinosaur diversity and extinction. They suggest that environmental factors may not be as crucial in determining the fate of these creatures as previously thought.
Source: https://www.yahoo.com/news/dinosaurs-werent-going-extinct-asteroid-150000252.html