Description and Classification

Blasisaurus was a large plant-eating dinosaur that could walk on both two legs and four legs, making it a facultative biped. Like other hadrosaurs, it had a characteristic broad, duck-like snout, which was well-suited for cropping vegetation. As a member of the Lambeosaurinae subfamily, Blasisaurus likely possessed a hollow crest on its head, although a complete crest has not yet been discovered for this specific genus. In related dinosaurs, such as Parasaurolophus or Corythosaurus, these crests are thought to have been used for making sounds or for visual display to other members of their species. Scientists estimate that Blasisaurus could have grown to be about 7 to 9 meters (23 to 30 feet) long.

Blasisaurus belongs to the family Hadrosauridae, a diverse group of ornithopod dinosaurs often called “duck-billed dinosaurs.” Within this family, it is classified as a lambeosaurine. Lambeosaurines are distinguished from other hadrosaurs (like saurolophines) by their prominent, often elaborate, hollow cranial crests. Blasisaurus is considered closely related to other European lambeosaurines, such as Arenysaurus, which was found in the same region of Spain, and Pararhabdodon, another Spanish hadrosaur.

Distinguishing Features

Identifying Blasisaurus from other hadrosaurs relies on specific details of its bones, as its remains are currently incomplete. Paleontologists have noted a unique combination of features in its skull and jaw bones that set it apart. Some of these distinguishing characteristics include:

• A maxilla (the main tooth-bearing bone of the upper jaw) that is relatively short from front to back but tall from top to bottom compared to some other hadrosaurs.
• Specific characteristics in the shape and connections of the jugal bone, which forms the cheek area below the eye.
• Particular features on the surangular bone, which is part of the lower jaw located towards the back.
• Details of the dentary, the main tooth-bearing bone in the lower jaw, also contribute to its unique identification.

These subtle anatomical details are crucial for scientists to differentiate Blasisaurus from its close relatives and to understand its specific place within the hadrosaur family tree.

Paleoenvironment and Diet

Blasisaurus lived in what is now northeastern Spain during the late Maastrichtian stage, at the very end of the Cretaceous period, shortly before the mass extinction event that wiped out the non-avian dinosaurs. The Arén Formation, where its fossils were found, represents an environment that was likely near the coast. During this time, Europe was largely an archipelago of islands, and Blasisaurus inhabited one of these landmasses. The climate was probably warm, and the landscape may have included river systems, floodplains, and forests, providing ample food resources.

As a hadrosaur, Blasisaurus was a herbivore. It had powerful jaws equipped with dental batteries – hundreds of teeth packed closely together that formed large grinding surfaces. These teeth were constantly being replaced as they wore down from chewing tough plant material. Blasisaurus would have used its broad, horny “duck bill” to gather leaves, twigs, ferns, and other vegetation, likely browsing on plants at low to medium heights. It shared its ecosystem with other dinosaurs, including predatory theropods (like dromaeosaurids), other plant-eating ornithopods, and possibly titanosaurian sauropods. The environment also supported crocodiles, turtles, and fish.

Significance and Ongoing Research

The discovery of Blasisaurus is significant because it adds to our understanding of dinosaur diversity in Europe during the final stages of the Cretaceous period. It provides evidence that lambeosaurine hadrosaurs were present and fairly diverse in the European archipelago right up until the end of the Mesozoic Era. Fossils like those of Blasisaurus offer valuable insights into the types of animals and ecosystems that existed just before the Cretaceous-Paleogene (K-Pg) extinction event. Its close relationship with other European hadrosaurs, such as Arenysaurus, helps paleontologists trace the evolutionary history and paleobiogeography of these large herbivores.

Ongoing research on Blasisaurus involves the continued detailed study of its known fossil material. Paleontologists are always hopeful that new expeditions to sites like Blasi 1 will yield more complete specimens, which could reveal more about its anatomy, particularly the precise shape and size of its potential cranial crest. Comparative studies with other hadrosaurs from Europe, North America, and Asia are crucial for refining our knowledge of its evolutionary relationships and the functional morphology of lambeosaurine features. This research contributes to a clearer picture of life at the very end of the Age of Dinosaurs in Europe.