A remarkably complete fossil discovered in northern Patagonia, Argentina, is reshaping our understanding of dinosaur evolution. Researchers have unearthed the remains of a tiny, agile dinosaur that lived at least 95 million years ago, offering unprecedented insight into a previously enigmatic group of creatures.
The dinosaur, named Alnashetri cerropoliciensis, meaning ‘small swift animal of Cerro Policía,’ is the smallest dinosaur yet discovered in South America. This discovery could significantly advance the study of prehistoric animals, according to a recent article in ‘Nature’.
The nearly complete skeleton, weighing less than 2 lbs, was initially discovered in 2014. Following a decade of careful preparation to protect its delicate bones, researchers led by University of Minnesota’s Peter Makovicky and Argentinean colleague Sebastián Apesteguía have now unveiled their findings. The identify provides a crucial reference point for understanding the evolution of alvarezsaurids, a family of bird-like dinosaurs.
Alnashetri belongs to the alvarezsaur family, a group that has long fascinated paleontologists due to their small size and resemblance to early birds. Previously, understanding of these creatures was hampered by the scarcity of well-preserved specimens, particularly in South America. “Going from fragmentary skeletons that are hard to interpret, to having a near complete and articulated animal is like finding a paleontological Rosetta Stone,” said Makovicky.
These dinosaurs were characterized by their small size, robust but short arms, a highly developed thumb, tiny teeth, and a lifestyle centered around digging in the surrounding terrain. The newly discovered specimen measures just over half a meter in length, with long hind legs and a slender torso, and was likely quite agile.
Why This Discovery Matters
The find indicates that South American alvarezsauroids are more diverse than previously thought, and are separated by older lineages. This challenges previous assumptions about the evolutionary history of the group. The recent data suggests these small animals did not travel between South America and Asia during the Cretaceous period.
For decades, well-preserved specimens were primarily found in Asia, leaving the South American fossil record incomplete and difficult to analyze. This discovery, detailed in a recent article in Nature, provides the missing data needed to map the group’s unique anatomy. The find underscores the importance of continued paleontological research in regions like Patagonia, which continue to yield crucial insights into the history of life on Earth, as reported by Phys.org and Interesting Engineering.
