Description and Classification

Camarillasaurus was a two-legged carnivorous dinosaur. Based on the known fossils, scientists estimate it was a medium-sized theropod, likely measuring around 4 to 5 meters (13 to 16 feet) in length. Its remains include vertebrae from the back and tail, ribs, and parts of the pelvis, including the ilium, pubis, and ischium. No skull bones or teeth have been found yet, which makes understanding its exact appearance and diet more challenging.

When Camarillasaurus was first studied, it was thought to be a type of ceratosaurian dinosaur. However, further research and more detailed comparisons with other theropods have led most paleontologists to classify it as a megalosauroid. More specifically, it is considered to be either a basal (early) member of the Spinosauridae family or very closely related to them. This means Camarillasaurus is an ancient relative of more famous spinosaurids like Baryonyx from England and Africa, and the giant Spinosaurus from North Africa.

Distinguishing Features

Camarillasaurus possesses several features that help paleontologists identify it and understand its place among dinosaurs. While based on incomplete remains, these include:

• A relatively small body size compared to many later spinosaurids.
• Specific characteristics in its vertebrae (backbones), such as relatively tall neural spines on some of its sacral (hip) vertebrae, although not forming a large sail like in Spinosaurus.
• The absence of pleurocoels (hollow openings for air sacs) on the front-most vertebrae of its tail, which is a feature shared with some other megalosauroids.
• Unique combination of features in its pelvic bones that differ from other theropods found in the same region.

Paleoenvironment and Diet

Camarillasaurus lived in what is now the Iberian Peninsula (Spain) during the Barremian age of the Early Cretaceous. The fossils were found in the Camarillas Formation, which represents an ancient environment of rivers, floodplains, and freshwater lakes. The climate was likely warm and relatively humid.

This dinosaur shared its habitat with a variety of other prehistoric life. Other dinosaurs found in or near the Camarillas Formation include plant-eating iguanodontians like Morelladon and Iguanodon, as well as other theropods and possibly sauropods. As a theropod dinosaur, Camarillasaurus was a carnivore. Given its likely relationship to spinosaurids, it might have hunted other dinosaurs or smaller animals. If it shared early spinosaurid traits, it might have also included fish in its diet, a common adaptation in more specialized spinosaurids known for their long snouts and conical teeth, though no skull material of Camarillasaurus has been found to confirm this directly.

Significance and Ongoing Research

The discovery of Camarillasaurus is important because it adds to our knowledge of the diversity of theropod dinosaurs in Europe during the Early Cretaceous period. Its changing classification, from a ceratosaur to a megalosauroid close to spinosaurids, highlights how scientific understanding of dinosaur relationships can evolve as new fossils are found and new analytical methods are used.

Camarillasaurus helps paleontologists understand the early evolution and geographic spread of the spinosaurid group, suggesting that relatives of these impressive predators were present in Europe early in their history. Ongoing research focuses on finding more complete remains of Camarillasaurus, which would help to clarify its exact anatomy, diet, and its precise position within the theropod family tree. Further studies of its fossils continue to provide insights into the ecosystems of ancient Spain.