Tiny predatory dinosaur weighed less than a chicken
New Scientist
February 25, 2026
AI-Generated Deep Dive Summary
A newly discovered nearly-complete skeleton of a tiny dinosaur, Alnashetri cerropoliciensis, has challenged previous theories about the evolution of alvarezsaurs. These small dinosaurs were once believed to have evolved specialized features like short forelimbs and reduced teeth due to their presumed diet of ants and termites. However, this new fossil, found in Argentina, reveals that Alnashetri had long, slender hind limbs and well-developed forelimbs with three fingers, more resembling typical theropods rather than specialist ant-eaters. Estimated to weigh less than a chicken, this adult dinosaur’s anatomy suggests it may have had a broader diet than previously thought.
The fossil, dating back 95 million years, was uncovered in 2014 at the La Buitrera site in Patagonia. Unlike earlier incomplete remains of Alnashetri, which left much to speculation, this complete skeleton provides critical insights into its biology and evolution. The dinosaur’s adult age and small size—about 700 grams—raise questions about why such tiny predators existed and how they adapted to their environments. Despite resembling birds in some ways, Alnashetri was a non-avian theropod, highlighting the complexity of alvarezsaur evolution.
This discovery complicates the idea that alvarezsaurs’ unique anatomy evolved solely for ant-eating. Alnashetri’s forearms and teeth show no signs of reduction, suggesting it may have hunted a variety of prey. This challenges paleontologists’ understanding of why these dinosaurs became so small and how they fit into ancient ecosystems. The find underscores the need for further research to unravel the ecological roles and evolutionary paths of these enigmatic creatures.
The study of Alnashetri adds depth to our knowledge of dinosaur diversity and adaptation. Its unexpected features remind us that even within specialized groups, there can be surprises in anatomy and behavior. For readers interested in science, this highlights how new fossils can reshaped understanding of ancient life and evolutionary processes. The story also emphasizes the importance of continued exploration
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Originally published on New Scientist on 2/25/2026