Reconstruction of Alnashetri cerropoliciensis Gabriel Díaz Yantén, Universidad Nacional de Río Negro. An almost-complete skeleton of a dinosaur that weighed less than a small chicken has provided new insights into the evolution of alvarezsaurs, which are among the smallest dinosaurs that ever lived. The 95-million-year-old fossil of Alnashetri cerropoliciensis was found at the La Buitrera site in northern Patagonia, Argentina, in 2014. The first specimen of Alnashetri, found in 2012, was a set of incomplete hindlimb bones, says Peter Makovicky at the University of Minnesota, who was part of the study on the new fossil. With only fragmentary remains, it was impossible to say more than that it was probably an alvarezsaur. “We were not even sure if it was a juvenile or fully grown,” he says. “With a whole skeleton, we suddenly had all the information to understand how Alnashetri was similar or differed from other species, and a key to understanding how the unusual anatomy of alvarezsaurs evolved,” says Makovicky. The new fossil has very long, slender hind limbs and surprisingly long forelimbs …