Description and Classification

Losillasaurus was a large, four-legged dinosaur with a long neck and a long tail, which is typical for sauropods. While it’s hard to know its exact size because its fossils are not complete, scientists believe it could have reached lengths of around 15 to 18 meters (about 50 to 60 feet) and weighed many tons. Like other sauropods, it would have used its long neck to reach high into trees to eat leaves.

In terms of classification, Losillasaurus belongs to a group of sauropods called Turiasauria. This group includes other giant European sauropods like Turiasaurus, which was even larger than Losillasaurus, and Zby. Turiasaurs are considered an older group that represents a distinct branch of sauropod evolution mainly found in Europe. The fossils of Losillasaurus include parts of the backbone (vertebrae), ribs, limb bones, and unique sternal plates (bones from the chest area).

Distinguishing Features

Losillasaurus had several features that help paleontologists identify it and distinguish it from other sauropods. These include:

• A specific combination of traits in its vertebrae (backbones), especially those from the front part of the tail, which had relatively short neural spines (the bony projections extending upwards from the vertebrae).
• Unusually large, heart-shaped sternal plates, which are bones that formed part of the chest and likely supported shoulder muscles.
• The structure of its forelimb bones, such as the humerus (upper arm bone), which show a particular mix of robust and somewhat slender characteristics compared to other large sauropods.
• Its classification as a turiasaur, sharing key characteristics with other members of this European sauropod group. This sets it apart from more well-known sauropods like Brachiosaurus from North America or Diplodocus.

Paleoenvironment and Diet

Losillasaurus lived in what is now Spain during the time when the Late Jurassic period was transitioning into the Early Cretaceous period. The environment at that time, shown by the rocks of the Villar del Arzobispo Formation, was likely a coastal plain with rivers, lakes, and possibly shallow sea inlets or lagoons. The climate was warm and supported a rich variety of plant life.

As a large herbivore (plant-eater), Losillasaurus would have needed to eat huge amounts of plants every day. Its long neck allowed it to browse on leaves and branches from tall trees. Its diet likely included conifers (like pine trees), cycads, and ferns, which were common plants during that era. Losillasaurus shared its habitat with other dinosaurs, including theropods (meat-eating dinosaurs) and other types of herbivores.

Significance and Ongoing Research

The discovery of Losillasaurus has been important for understanding how sauropod dinosaurs evolved and the variety that existed, especially in Europe. It was one of the first large sauropods described from Spain that helped to show the existence of the Turiasauria group. This proved that Europe had its own unique families of giant dinosaurs, different from those found on other continents at the same time.

Ongoing research on Losillasaurus focuses on several areas. Paleontologists continue to study its known fossils to better understand its body structure and how it moved and lived. They are also searching for more complete skeletons, which could tell us more about its true size and appearance. Further research also aims to find its exact place in the sauropod family tree and learn more about the ancient environments of Spain where Losillasaurus lived. Comparing Losillasaurus with other turiasaurs like Turiasaurus helps paint a clearer picture of this group’s evolution and where they lived.