Tiny dinosaur shakes up paleontology in Spain

Paleontologists in Spain have identified Foskeia pelendonum, a new dinosaur species about the size of a chicken, that is challenging long-held beliefs about dinosaur evolution.

Researchers first discovered the dinosaur’s bones in the Castrillo de la Reina geological formation in 1998, but struggled to determine if the remains belonged to a juvenile of a larger species.

For decades, paleontologists have classified dinosaurs based on their hip structure, dividing them into two main groups: the Saurischia (including Tyrannosaurus rex) and the Ornithischia (including Stegosaurus and Triceratops). However, a gap existed in the fossil record for a subgroup of Ornithischia called Rhabdodontomorpha, scientists knew of early and later forms, but lacked evidence of what existed during a 70-million-year period. Foskeia fills that gap.

Using computer micro-tomography, a team led by Paul-Emile Dieudonné of the Universidad Nacional de Río Negro determined that at least one of the examined fossils represented a fully grown adult. This small herbivore, measuring about half a meter long, had a specialized diet and likely moved quickly through forests to avoid predators.

The discovery also reignites debate about the "Phytodinosauria" hypothesis, which suggests all herbivorous dinosaurs may share a closer common ancestor than previously thought, potentially requiring a complete re-evaluation of the dinosaur family tree.