Austrocheirus

Austrocheirus is an extinct genus of theropod dinosaur that lived during the Late Cretaceous period, about 76 to 70 million years ago.

It was named and described by Martin Ezcurra, Federico Agnolin and Fernando Novas in 2010.

The generic name means "southern hand" and the specific name honours Marcelo Pablo Isasi, who prepared most of the fossils.

Austrocheirus was originally classified as a member of Abelisauroidea, a group of mostly small-armed carnivorous dinosaurs that were common in the southern continents.

However, Austrocheirus had a relatively large and well-developed hand, unlike most other abelisauroids, which had reduced or atrophied forelimbs.

This suggested that Austrocheirus was a more primitive or basal abelisauroid, or that it evolved its large hand independently.

However, some later studies challenged the assignment of Austrocheirus to Abelisauroidea, arguing that the features used to support this classification were not unique to abelisauroids, but also present in other theropods.

Therefore, Austrocheirus could not be confidently placed in any specific group of theropods, and was considered to have an uncertain phylogenetic position.

Austrocheirus is one of the few known theropods from the Late Cretaceous of Patagonia, and its discovery sheds light on the diversity and evolution of this group of dinosaurs in this region.

Austrocheirus was an extinct genus of theropod dinosaur that belonged to the group of Abelisauroidea.
It lived during the Late Cretaceous period, about 71 to 65 million years ago, on the territory of present-day South America.
Austrocheirus was a medium-sized theropod, measuring 5.5 to 6.5 meters (18 to 21 feet) long.
It was one of the few abelisauroids that did not have reduced forelimbs, as seen in other members of that clade.
The exact phylogenetic position of Austrocheirus within Abelisauroidea is uncertain, as some features of its skeleton are also present in other theropods.
Therefore, it is best to classify this genus as incertae sedis (of uncertain placement) within Averostra, a larger group of theropods that includes Abelisauroidea.