Aragosaurus

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Massopoda > Sauropodiformes > Sauropoda > Gravisauria > Eusauropoda > Neosauropoda > Macronaria

Overview: Fossilized remains attributed to Aragosaurus are known from the rock layers of Spain’s Villar del Arzobispo Formation, in the region of Aragón. Described in 1987, the genus’s name was chosen in reference to this locality. Studies of the Villar del Arzobispo have found that it dates to a fairly wide swath of time, spanning the Late Jurassic and Early Cretaceous. Aragosaurus was found within rocks believed to date to quite early in the Cretaceous, or to about one hundred and forty million years ago. The region was a seasonal, coastal plain at that time, hosting a wide variety of dinosaurs including stegosaurs, ornithopods, other sauropods, and some large theropods. When it reached adulthood, Aragosaurus had little to fear from most theropods, excluding the largest, but as a juvenile that was another story. It possibly lived in groups for added protection.

The overall appearance of Aragosaurus was superficially similar to that of Camarasaurus. Both of these dinosaurs were basal macronarian sauropods, though Aragosaurus isn’t typically classified as a camarasaurid specifically. Between the two, Camarasaurus was probably more “primitive”. Most of the fossils we have of Aragosaurus consist of its vertebrae, limb bones, and pelvic material, so its skull remains a mystery. It’s often reconstructed in a manner similar to that of Camarasaurus, with a boxy shape and fairly robust teeth. Length estimates put it at maybe eighteen meters, with a heavy build, so it was decently large as far as sauropods go. It was probably a mid to high-level browsing herbivore, eating from conifers and other trees. Some phylogenetic studies have placed this animal within the clade Titanosauriformes, making it potentially related to Brachiosaurus and its kin.