Overview

• Researchers formally described Joaquinraptor casali from the Lago Colhué Huapi Formation in Chubut, based on a partially articulated skeleton that includes a partial skull, vertebrae, ribs and limb bones.
• Bone histology identified at least 19 growth lines, and the team estimates the animal was about 7 meters long and weighed more than one tonne.
• Its stratigraphic position very close to the Cretaceous–Paleogene boundary makes it among the latest-known megaraptorans.
• A crocodiliform humerus preserved between the jaws suggests predation or scavenging on crocodilians, though the authors emphasize the evidence is not conclusive.
• Phylogenetic analyses place megaraptorans nearer coelurosaurs—potentially sister to tyrannosaurids in some datasets—and sedimentology indicates a warm, humid, coastal setting where megaraptorids likely served as top predators in southern and central Patagonia.