Two-Pound Patagonian Dinosaur Rewrites Evolutionary History
A near-complete 90-million-year-old skeleton of Alnashetri cerropoliciensis from Patagonia shows that some alvarezsaurs were tiny before developing their characteristic short arms with a single large claw, suggesting body-size reduction preceded extreme specialization. At under two pounds, Alnashetri was an adult—one of the smallest non-avian dinosaurs in South America—and its fossil clarifies the group’s evolution and distribution, with the La Buitrera site continuing to yield insights and the study published in Nature.
