Aucasaurus Archives - The Big Dinosaur Podcast

Episode 113 is all about Aucasaurus, an abelisaurid that lived in the late Cretaceous in what is now Argentina.

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In this episode, we discuss:

The dinosaur of the day: Aucasaurus
A medium-sized carnivorous theropod that live in the late Cretaceous in what is now Argentina

Found in a joint expedition in 1999 with the Museo Municipal Carmen Funes and the Natural History Museum of LA
Named in 2002 by Coria, Chiappe, and Dingus
Type species is Aucasaurus garridoi

Found in Auca Mahuevo, a Patagonian site where many sauropod eggs and embryos have been found
Name “Auca” comes from the Mapuche language, and refers to where it was found
The species name “garridoi” is in honor of Alberto Garrido, who found the holotype

Most complete abelisaurid that has been described so far (only the end of the tail is missing)
Because the specimen found is so complete, it helped clarify the postcranial anatomy of Carnotaurus and other abelisaurs
Related to Carnotaurus, but smaller

About 20 ft (6.1 m) long
Had low ridges above its eyes (not horns, like Carnotaurus)
Had small arms, and only two fingers (second and third digits) but they were short and didn’t have claws

Had a short, deep-snouted skull
Skull found is damaged, may be due to a fight before death
Skull damage probably from another dinosaur, and the damage is limited to the skull, so it probably was attacked

Attack could be by fighting a large herbivore, fighting over food or territory, or even attempted cannibalism (like abelisaurid Majungasaurus may have done)
Probably died from its skull injury
Where the fossils were found used to be a lake, so Aucasaurus either was injured in the lake or walked to the lake with its injury and sank to the bottom (either way, because of that, terrestrial predators couldn’t get to it, which is why it’s so well preserved)

Can see Aucasaurus in Dinosaur Planet, a 2003 documentary series, where a Saltasurus fell on top of Aucasaurus and crushed its skull
Can also see Aucausaurus art on DeviantArt, created by Joschua Knuppe, who created an Aucausaurus mother as part of a concept for Global Dinosaur Monument, a park on a small peninsula on the Australian coast
Carnotaurinae is a subfamily of Abelisauridae

Subfamily includes Aucasaurus, Carnotaurus, and Rajasaurus
Fun fact: There are at least a couple accounts of mammals eating non-avian dinosaurs. The first that was found was Deltatheridium eating an Archaeornithoides in present day Mongolia. The mammal Deltatheridium was weasel-sized at half a foot (15cm) long. The evidence isn’t great though, basically a partial Archaeornithoides skull was found which appeared to have been chewed on (or possibly eaten) by the mammal. The second discovery was of a Repenomamus with a Psittacosaurus found preserved in its stomach. The mammal was about 2 feet long, and likely weighed between 4-6Kg (9-13lb), making it about the size of an opossum. And in both cases the dinosaurs were juveniles. Random other fact… The U.S. President Taft celebrating his election ate a roasted opossum. He was replacing Teddy Roosevelt (who the Teddy Bear was named after) and there was a brief attempt to make a “Billy Possum”. It failed catastrophically. Maybe they should have made a dinosaur stuffed animal instead… Taft rex?

This episode was brought to you by:

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