Birds and theropods in Patagonia during the Late Cretaceous period. (Image credit: Mauricio Alvarez and Gabriel Diaz).
The researchers focused on theropod fossils from the Chilean portion of Patagonia
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- The study provides a better understanding of fossil dinosaurs from South America.
- The findings can help better assess the biodiversity among dinosaurs during the Late Cretaceous.
- The fossils reported are the southernmost finds of theropods outside Antarctica.
Researchers have investigated a number of fossils discovered in Patagonia since 2017, providing a glimpse into the biodiversity of the region during the Late Cretaceous period, between 66 and 78 million years ago. The fossils record a number of theropod groups that are the southernmost regions from where the discoveries have been made, outside of Antarctica. Most of the theropods were carnivorous dinosaurs, often at the top of food webs, although there were species that were herbivorous and omnivorous. Theropods included non-avian dinosaurs as well as birds. The research provides a better understanding of theropod species, especially when it comes to the smaller animals.
The paper describes megaraptors, which were giant dinosaurs with scythe-like claws, that could reach seven and a half metres in length, and were among the largest theropods in Patagonia during the Late Cretaceous. Another group, unenlagiines, close relatives of velociraptors, had members that were between chicken sized and three metres tall, and were covered with feathers. Modern birds descended from a group known as the ornithurines, which had short, fused tails as against the long tails characteristic of non-avian theropods. Then there were the enantiornithines, creatures that looked like birds but had teeth, and clawed feathers on their wings.
Lead author of the study, Sarah Davis says, “The fauna of Patagonia leading up to the mass extinction was really diverse. You’ve got your large theropod carnivores and smaller carnivores as well as these bird groups coexisting alongside other reptiles and small mammals.” Many of the theropods identified are based on fragments of bones, mostly teeth and toes. The enamel on the teeth of the dinosaurs allowed the fossils to be easily spotted, with the region being a particularly suitable place for hunting fossils from the Late Cretaceous. A paper describing the findings has been published in the Journal of South American Earth Sciences.