A remarkably preserved dinosaur skeleton unearthed in Patagonia is offering new insight into one of prehistory’s most puzzling groups of creatures.
The 90-million-year-old fossil was identified by a team co-led by University of Minnesota Twin Cities researcher Peter Makovicky and Argentine palaeontologist Sebastian Apesteguía.
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Their findings, published in Nature, describe a complete skeleton of
Alnashetri cerropoliciensis, a member of the alvarezsaurs, bird-like dinosaurs known for tiny teeth and short arms tipped with a single large thumb claw.
For decades, alvarezsaurs remained enigmatic because most well-preserved fossils were discovered in Asia, while South American examples were fragmentary and difficult to interpret.
The nearly complete
Alnashetri fossil was found in 2014 in northern Patagonia, Argentina, at the La Buitrera fossil area, a site renowned for its rich Cretaceous discoveries.
Although the species had been named from partial remains, the new specimen allowed researchers to reconstruct its distinctive anatomy after nearly 10 years of careful preparation to protect the fragile bones.
Makovicky described the find as “like finding a palaeontological Rosetta Stone,” saying it provides a reference point for identifying other fragmentary fossils and understanding evolutionary changes in anatomy and body size.
Apesteguía added that more than two decades of work at La Buitrera have revealed rare insights into small dinosaurs and other vertebrates in South America, noting that further alvarezsaurid material from the site is already being prepared in the laboratory.
