Dinosaurs weren't declining before the asteroid—our fossil discovery skills are lacking
Dinosaurs thrived before the asteroid, new fossil analysis shows.
A recent study published in 'Current Biology' challenges the long-held belief that dinosaurs were already on the decline before the asteroid impact 66 million years ago. Researchers from the United States, United Kingdom, and China conducted extensive analysis on North American dinosaur fossils, particularly focusing on those dated between 84 and 66 million years ago. Chris Dean, a paleontology research fellow at University College London who led the study, argued that the observation of declining fossil records could be misleading.
The team's research involved analyzing fossils from the Ankylosauridae, Ceratopsidae, Hadrosauridae, and Tyrannosauridae families. They noted that approximately 50% of fossils found from this time period originated from North America, specifically the Western Interior Basin (WIB), an ancient region split by a large body of water. By reconstructing the region's paleoenvironment and using mathematical models similar to modern biodiversity studies, they discovered that population levels among these dinosaur families remained stable rather than experiencing a decline.
In an effort to understand the discrepancy between the fossil record and their findings, researchers examined the change in terrain and fossil discovery patterns. They identified factors that may hinder discovering fossils today, such as exposed rock scarcity, inaccessible areas, and overlooked regions by paleontologists. The results showed that although dinosaurs lived in various habitats, the odds of finding their fossils have diminished significantly.
The implications of these findings urge a reconsideration of previously held beliefs about dinosaur extinction events. It suggests that various dinosaur species may have been flourishing prior to the asteroid impact, but changes in geology and paleontological survey practices have skewed our understanding.
This research not only offers a new perspective on dinosaur extinction but also serves as a guidepost for further exploration. Expanding future fossil hunts to areas previously deemed unpromising, the study invites paleontologists to revisit assumptions and potentially uncover a broader array of dinosaur species that lived towards the end of the Cretaceous period.
Sources: Current Biology, University College London, Western Interior Basin studies