Camarillasaurus

Camarillasaurus is an extinct genus of theropod dinosaur that roamed the Earth during the Early Cretaceous period, specifically the Barremian stage. Its fossils were unearthed in the Camarillas Formation of Teruel Province, in what is now northeastern Spain. The genus name, "Camarillasaurus," translates to "Camarillas lizard," referencing the geological formation where its holotype was discovered, combined with the Greek word "sauros" meaning "lizard." The species epithet, "cirugedae," honors Pedro Cirugeda Buj, the individual credited with discovering the holotype specimen.

Taxonomic History and Classification

The classification of Camarillasaurus has undergone significant revision since its initial description. In 2014, palaeontologists Bárbara Sánchez-Hernández and Michael J. Benton described it as a basal ceratosaurian theropod, suggesting it filled a gap in the known diversity of this clade. However, subsequent research has increasingly pointed towards a different taxonomic placement. Studies presented from 2019 onwards, including those by Oliver Rauhut and colleagues, and a 2021 paper by Samathi, Sander & Chanthasit, proposed affinities with the Spinosauridae family. These conclusions were based on analyses of posterior caudal vertebrae and newly excavated materials. Further support for this spinosaurid affiliation came in 2021 when Camarillasaurus was recovered as the basalmost member of the Spinosaurinae in a description of Wessex Formation baryonychines. In 2023, Santos-Cubedo et al. placed it as the basalmost member of Spinosauridae in their phylogenetic analysis. A 2024 review by Mohabey et al. controversially placed it within the ceratosaurian clade Noasauridae, though this analysis did not include any spinosaurids. In contrast, a 2024 description of the Iberian spinosaurid Riojavenatrix by Isasmendi et al. once again placed Camarillasaurus within Spinosauridae. Most recently, in 2025, Rauhut and colleagues found high support for its placement within Spinosaurinae, as the sister taxon to a clade comprising Spinosaurus and a Kem Kem spinosaurid specimen.

Paleontological Significance

Camarillasaurus is notable as one of several spinosaurid taxa identified on the Iberian Peninsula, alongside genera such as Iberospinus, Protathlitis, Baryonyx, Riojavenatrix, and Vallibonavenatrix. Its evolving classification highlights the complex nature of theropod systematics and the ongoing efforts to refine our understanding of dinosaur evolution and distribution during the Cretaceous period.