Discovery of Tiny Dinosaur Foskeia pelendonum Sheds Light on Ornithopod Evolution

Paleontologists have identified a new species of small ornithopod dinosaur, Foskeia pelendonum, from Early Cretaceous deposits in Vegagete, Burgos, Spain. Measuring approximately half a meter in length, this diminutive herbivore exhibits a highly derived skull, positioning it near the origin of the European Rhabdodontidae lineage. The findings, led by Paul-Emile Dieudonné of the National University of Río Negro, Argentina, are detailed in the journal Papers in Palaeontology.

The fossils, representing at least five individuals, were initially uncovered by Fidel Torcida Fernández-Baldor of the Dinosaur Museum of Salas de los Infantes. He noted the exceptional nature of the bones due to their minute size and the implications for understanding ornithopod evolution.

The genus name Foskeia is derived from ancient Greek, with 'fos' meaning 'light' and 'skei' from 'boskein,' meaning 'foraging.' The species name pelendonum honors the Pelendones, a Celtiberian tribe from the region.

Histological analysis supervised by Dr. Koen Stein of Vrije Universiteit Brussel confirmed that the largest specimen was a sexually mature adult, indicating that the small size was not due to immaturity. The bone microstructure suggests a metabolic rate comparable to small mammals or birds.

Phylogenetic analysis places Foskeia as a sister taxon to the Australian Muttaburrasaurus within Rhabdodontomorpha, expanding the European clade Rhabdodontia. The study also revives the Phytodinosauria hypothesis, grouping plant-eating dinosaurs into a natural clade.

Despite its small stature, Foskeia possessed specialized dentition and evidence of postural changes during growth, suggesting adaptations for rapid movement through dense forests. Dieudonné emphasized that these fossils demonstrate significant evolutionary experimentation at small body sizes, highlighting the importance of studying even the most modest specimens to fully understand dinosaur evolution.