“Newly Discovered Dinosaur Species Challenges Decline Theory Before Asteroid Impact”

Newly Discovered Dinosaur Species Challenges Decline Theory Before Asteroid Impact

In the world of paleontology, there has long been a debate about whether dinosaurs were already on the decline before the catastrophic asteroid impact that ended the Cretaceous period. For over 40 years, scientists have been trying to unravel this mystery. Recent discoveries, however, are challenging the prevailing theory and shedding new light on the diversity of dinosaurs during this crucial time.

Back in the late 1970s, researchers noticed a peculiar pattern in the fossil record. While dinosaur diversity seemed to have increased during a specific period of the Cretaceous, it appeared to decrease in the last few million years leading up to the asteroid impact. Some scientists interpreted this as evidence that dinosaurs were already in decline before the catastrophic event. However, others argued that this decrease in diversity might be due to biases in fossil preservation and sampling.

To get a clearer picture of what was happening to dinosaur diversity at that critical moment, paleontologists have turned to the discovery of new species. One recent study focused on a set of hindlimb bones unearthed in South Dakota, dating back to the final 2 million years of the Cretaceous. Initially identified as belonging to a known species of birdlike dinosaur called caenagnathids, further examination revealed that they belonged to an entirely new species.

The bones, which were significantly smaller than those of the previously known caenagnathid species, led researchers to believe that they were from a juvenile dinosaur. However, microscopic analysis of the bone structure showed otherwise. The lines of arrested growth within the bones indicated that this dinosaur had reached its adult size and was not a juvenile as initially assumed. This discovery led to the identification of a new species named Eoneophron infernalis.

Eoneophron infernalis possessed unique traits such as ankle bones fused to the tibia and a well-developed ridge on one of its foot bones. These features were not something a young Anzu, a larger cousin of Eoneophron, would outgrow. This finding expanded the caenagnathid family tree and prompted researchers to reexamine other bones previously believed to belong to Anzu. As a result, they discovered evidence for a third caenagnathid species, smaller in size.

Comparisons with older fossil formations revealed that the number of caenagnathid species and their relative sizes remained consistent throughout the late Cretaceous period. This suggests that caenagnathids were not declining in diversity before the asteroid impact. Instead, it indicates that there are still undiscovered species waiting to be found and that the perceived decline in diversity may be due to biases in fossil preservation and sampling.

These new findings challenge the notion that dinosaurs were already on their way out before the asteroid impact. The discovery of Eoneophron infernalis adds to the growing body of evidence that caenagnathids were thriving during this time. While many questions about dinosaur extinction remain unanswered, this study highlights the importance of continued exploration and the potential for exciting discoveries in the field of paleontology.