Tag Archive for: paleotology

A dino article to contemplate over your lunch break—evidence of paleoenvironments and how they may have existed.


Relationships between non-avian theropod dinosaurs and extant and fossil birds are a major focus of current paleobiological research. Despite extensive phylogenetic and morphological support, behavioural evidence is mostly ambiguous and does not usually fossilize. Thus, inferences that dinosaurs, especially theropods displayed behaviour analogous to modern birds are intriguing but speculative. Here we present extensive and geographically widespread physical evidence of substrate scraping behavior by large theropods considered as compelling evidence of “display arenas” or leks, and consistent with “nest scrape display” behaviour among many extant ground-nesting birds. Large scrapes, up to 2 m in diameter, occur abundantly at several Cretaceous sites in Colorado. They constitute a previously unknown category of large dinosaurian trace fossil, inferred to fill gaps in our understanding of early phases in the breeding cycle of theropods. The trace makers were probably lekking species that were seasonally active at large display arena sites. Such scrapes indicate stereotypical avian behaviour hitherto unknown among Cretaceous theropods, and most likely associated with terrirorial activity in the breeding season. The scrapes most probably occur near nesting colonies, as yet unknown or no longer preserved in the immediate study areas. Thus, they provide clues to paleoenvironments where such nesting sites occurred.



Fossil remains of an athletic sauropod with a potentially mighty kick found in eastern Utah offer a rare bounty of clues into how four-legged herbivores thrived, according to a new study of the discovery.

The results, published this week in the British journal Acta Palaeontologica Polonica, show that an unusually large hip bone compared to other sauropods could mean that the Brontomerus Mcintoshi had powerful hind legs to kick away predators, such as raptors.

“This is a very exciting discovery, because a majority of sauropods were known to have lived during the Jurassic period, but these fossils show us that they lived well into the early Cretacious period,” said Mathew Wedel, an assistant professor of anatomy at the Western University of Health Sciences in Pomona, Calif.

The fossils were excavated by American scientists in the mid-1990s.


*correction: Jim Kirkland is the state paleontologist for the Utah Geological Survey.