Tiny Dinosaur Roamed Beside Giants in Patagonia

Ninety-five million years ago, Patagonia was home to colossal dinosaurs like Giganotosaurus and Argentinosaurus. However, a recent fossil discovery reveals this ancient landscape also harbored one of the world's smallest dinosaurs, named Alnashetri cerropoliciensis.

This nearly complete skeleton, nicknamed 'Alna,' was unearthed in Rio Negro Province. Alnashetri was roughly the size of a crow, weighing about 0.7 kg, and likely hunted small prey. Its exceptional preservation, due to rapid burial by a sand dune, offers scientists a rare glimpse into the lives of these diminutive creatures.

Alna belonged to the alvarezsaurs, an unusual group of theropods. While some later alvarezsaurs specialized in insectivory with reduced arms, Alnashetri possessed numerous sharp teeth and well-developed forelimbs, suggesting a broader diet. This find demonstrates that significant size reduction occurred multiple times within this dinosaur lineage.

The discovery challenges the common perception of dinosaur-dominated landscapes as solely populated by giants. Alnashetri's existence highlights the immense biodiversity of the Cretaceous Period, revealing a complex ecosystem that included a wide range of animal sizes.