Description and Classification

Concavenator was a medium-sized meat-eating dinosaur, measuring around 6 meters (about 20 feet) in length and likely weighing about 1 ton. Like other theropods, it walked on two strong hind legs and had a long tail to help it balance. Its arms were relatively short but possessed sharp claws. Concavenator belongs to the family Carcharodontosauridae, a group of large carnivorous dinosaurs recognized by their sharp, blade-like teeth, similar to those of sharks. Other well-known members of this family include giant predators such as Carcharodontosaurus and Giganotosaurus, although Concavenator was considerably smaller than these relatives. The discovery of an almost complete skeleton has provided scientists with a wealth of information about Concavenator‘s body structure and its evolutionary relationships, suggesting it was a relatively early member of the carcharodontosaurid lineage.

Distinguishing Features

Concavenator possessed several unique characteristics that set it apart from other known dinosaurs. These include:

• A prominent, narrow, and tall bony crest or “hump” on its lower back, located just in front of its hips. This unusual structure was formed by two vertebrae (backbones), the eleventh and twelfth, which were greatly elongated. Scientists are still debating the exact purpose of this hump. It might have been used for visual display to attract mates or intimidate rivals, for storing fat reserves, or possibly to help regulate its body temperature.
• A series of small, regularly spaced bumps along its ulna (one of the forearm bones). These features have been interpreted by some paleontologists as “quill knobs.” Quill knobs are known in modern birds and some other feathered dinosaurs like Velociraptor, where they serve as attachment points for large, stiff feathers. If this interpretation for Concavenator is correct, it would suggest that it had some form of feather-like structures on its arms, which is very interesting as Concavenator belongs to a group of dinosaurs not previously known to have such complex integument.
• A relatively long and low skull for its body size, housing many sharp, serrated teeth well-suited for slicing the flesh of its prey.

Paleoenvironment and Diet

Concavenator lived in what is now the province of Cuenca in Spain during the Barremian age of the Early Cretaceous period. The specific location where its fossils were found, known as the Las Hoyas fossil site, was a subtropical wetland environment at that time. This ancient ecosystem featured shallow lakes, rivers, and abundant plant life, creating a rich habitat for many different species. Fossils from Las Hoyas reveal a diverse community of animals that lived alongside Concavenator, including various types of fish, amphibians like frogs and salamanders, lizards, turtles, crocodiles, flying reptiles called pterosaurs, early species of birds, and other dinosaurs, such as the plant-eating iguanodontian Mantellisaurus.

As a member of the Carcharodontosauridae family, Concavenator was a carnivore, meaning it primarily ate meat. Its sharp teeth, agile build, and predatory instincts indicate that it hunted other animals within its wetland habitat. Its prey likely included smaller dinosaurs, lizards, and possibly fish or crocodiles, taking advantage of the diverse fauna available in the Las Hoyas ecosystem.

Significance and Ongoing Research

The discovery of Concavenator is highly significant for paleontology for several reasons. The single specimen is exceptionally well-preserved, providing a nearly complete skeleton. This offers invaluable insights into the anatomy and evolution of carcharodontosaurids, a group of dinosaurs for which complete remains are relatively rare. The unique hump on Concavenator‘s back is a feature not seen in quite the same way in any other dinosaur, prompting much discussion and research into its possible function and how such structures evolved over time. Perhaps the most talked-about aspect of Concavenator is the series of bumps on its ulna, interpreted by its describers as potential quill knobs. If confirmed, this finding would substantially broaden our understanding of feather evolution in theropod dinosaurs, suggesting that feather-like structures on the arms might have been present much earlier and in a more diverse range of theropods than previously thought, potentially including ancestors of large theropods like Allosaurus.

Ongoing research continues to focus on these remarkable features. Scientists are conducting further studies on the vertebral hump to better understand its internal structure, possible muscle attachments, and plausible functions. Detailed comparative analyses of the ulnar bumps are crucial to determine definitively whether they are quill knobs or represent another type of bony growth or pathology. Additionally, researchers are working to refine Concavenator‘s precise placement within the Carcharodontosauridae family tree and to build a more complete picture of its ecological role within the unique Las Hoyas wetland environment of the Early Cretaceous.