"The moment one lays eyes on this creature, its remarkable smallness is astonishing," remarks Dieudonné. "Yet, it features a highly developed skull with surprising anatomical traits."
Fossils That Challenge Established Beliefs
Found from at least five specimens, the fossils were initially uncovered by Fidel Torcida Fernández-Baldor from the Dinosaur Museum of Salas de los Infantes. Their diminutive size was immediately striking.
"Right from the start, we recognized these bones were extraordinary due to their tiny dimensions. The way this animal's study reshapes global perspectives on ornithopod dinosaur evolution is equally impressive," he notes.
The Meaning Behind the Name Foskeia pelendonum
The term Foskeia is derived from ancient Greek, where 'fos' signifies 'light', a nod to the exceptionally small and lightweight adult forms (Dieudonné et al. 2023). The suffix 'skei' comes from boskein, which means foraging. The species name pelendonum pays tribute to the Pelendones, a Celtiberian tribe that once inhabited the Fuentes del Duero area (located north of Soria, southeast of Burgos, and perhaps in the southeast of La Rioja).
The Significance of This Dinosaur in Evolutionary Research
Experts assert that Foskeia is crucial for a deeper understanding of dinosaur evolution. Marcos Becerra from Universidad Nacional de Córdoba emphasizes that small size does not equate to simplicity: "Miniaturization does not imply evolutionary simplicity--this skull is unique and highly specialized."
Thierry Tortosa from Sainte Victoire Natural Reserve underscores its wider implications: "Foskeia bridges a 70-million-year gap, serving as a small key to unlock a vast missing chapter."
Tábata Zanesco Ferreira from Universidade Federal do Rio de Janeiro adds, "This is not a 'mini Iguanodon'; it represents something fundamentally distinct."
According to Penélope Cruzado-Caballero from Universidad de La Laguna, "Its anatomy is peculiar in a way that fundamentally alters evolutionary trees."
Bone Structure Reveals Adult Size and Rapid Metabolism
Microscopic examination of the bones, led by Dr. Koen Stein from Vrije Universiteit Brussel, indicates that the largest fossil belonged to a fully grown adult. The internal bone structure provides vital insights into growth and metabolism.
"Bone microstructure indicates that at least one specimen was an adult... showing a metabolic profile similar to that of small mammals or birds. Understanding growth and development is crucial for comparing Foskeia's anatomy with other species. Young individuals often exhibit anatomical changes as they mature," Stein explains.
A New Position on the Dinosaur Family Tree
Utilizing updated evolutionary models, the research team found that Foskeia is closely related to the Australian dinosaur Muttaburrasaurus, placing it within the Rhabdodontomorpha group. This discovery also enhances the known diversity of the European clade Rhabdodontia.
The analysis further supports the revival of a long-discussed grouping called Phytodinosauria. "Our findings show that herbivorous dinosaurs form a natural group known as Phytodinosauria," states Dieudonné. "This hypothesis warrants further testing with additional data."
Small Size, Specialized Lifestyle
Despite its diminutive stature, Foskeia was well-suited to its environment. It possessed specialized teeth and seems to have altered its posture as it matured, utilizing short bursts of speed to navigate through dense forest habitats.
"These fossils demonstrate that evolution experimented just as boldly at smaller sizes as it did with larger ones," Dieudonné concludes. "The future of dinosaur research will rely on focusing on the humble, the fragmentary, and the small."
