Tiny alvarezsaurid upends the dinosaur miniaturization narrative
A newly described Alnashetri cerropoliciensis from Argentina weighs about 700 g and challenges the idea that Alvarezsaurid miniaturization evolved linearly from ant-eating; it’s a small, early-branching predator with relatively long forelimbs, suggesting tiny body size evolved multiple times and across a broader geographic range than previously thought, implying a Pangaea-wide distribution with later fragmentation shaping their Late Cretaceous distribution. Researchers plan CT scans of the specimen and have found hints of another Alvarezsaur in the region to help illuminate the next evolutionary steps.