Scientists writing in the academic journal “Cretaceous Research” have described theropod dinosaur remains from Lower Cretaceous deposits in Spain.  The fossils come from the province of Soria. They represent theropods excavated from the Western Cameros sub-basin.  Ironically, it is the eastern parts of the Cameros sub-basin that have yielded the majority of theropod remains.  In addition to mapping the Early Cretaceous theropod record, the researchers report evidence of a giant spinosaurid from this region.  Known as the Zorralbo I baryonychine, it is the largest Lower Cretaceous theropod described to date from Iberia.

The Zorralbo I baryonychine size estimate. Human figure provides the scale. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Zorralbo I Baryonychine

In the Cameros Basin, theropods have been mostly documented in the Eastern Cameros sub-basin with baryonychine spinosaurids dominating the theropod biota. Theropods are much rarer in the Western Cameros sub-basin.  The authors describe fossils from the Western Cameros sub-basin, recovered in the upper Hauterivian–lower Barremian Golmayo Formation of the Soria province. Specifically, the theropod remains come from the Los Caños and Zorralbo I sites, which are located in the Las Camaretas and the Zorralbo areas, respectively, south-east of the main town of Golmayo.

The theropod record from the Iberian Peninsula is highly fragmentary.  However, in this paper, the authors identified the presence of three early-branching members of the Tetanurae along with three baryonychine dental morphotypes.  In addition, an enormous spinosaurid was identified.  Anatomical and phylogenetic study of the skull, post-cranial and appendicular (limb) bones suggest that this huge spinosaurid is also likely to be a baryonychine.

Whereas the Early Cretaceous theropod record is represented by carcharodontosaurians, coelurosaurians and tetanurans, it is the spinosaurids that are the most prominent.  Spinosaurs seem to be the dominant theropods of these Lower Cretaceous deposits.

Five Spinosauridae Genera

To date, five spinosaurid genera have been described from the Iberian Peninsula.  Although, there are many more genera likely to be present.

The five members of the Spinosauridae described so far:

• Iberospinus natarioi – to read our blog post about this theropod: A New Spinosaurus from Portugal.
• Protathlitis cinctorrensis – our blog post about this new dinosaur: Protathlitis – Member of the Spinosauridae Family.
• Riojavenatrix lacustris – named in 2024 (Isasmendi et al).
• Vallibonavenatrix cani – named in 2019 (Malafaia et al).
• Camarillasaurus cirugedae – named in 2014 (Sánchez-Hernández and Benton).

The Cameros Basin could provide an excellent analogue for the theropod biota of the Iberian Peninsula.

The scientific paper: “A giant spinosaurid from the Iberian Peninsula and new data on the Early Cretaceous Iberian non-avian theropod palaeodiversity” by Erik Isasmendi, Elena Cuesta, Adrián Páramo and Xabier Pereda-Suberbiola published in Cretaceous Research.

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