Hypracosaurus Dorsal Vertebra
Cretaceous - 75 Million Years Ago
Private Quarry, Two Medicine Formation, Montana
Specimen size: approximately 7" x 4" x 2.5", height in stand is approximately 7.5". Custom metal stand included.
Hypacrosaurus (meaning "near the highest lizard" [Greek υπο-, hypo- = less + ακρος, akros, high], because it was almost but not quite as large as Tyrannosaurus) was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight. It is known from the remains of two species that spanned 75 to 67 million years ago, in the Late Cretaceous of Alberta, Canada, and Montana, USA, and is the latest hollow-crested duckbill known from good remains in North America. It was an obscure genus until the discovery in the 1990s of nests, eggs, and hatchlings belonging to H. stebingeri .
Hypacrosaurus is most easily distinguished from other hollow-crested duckbills (lambeosaurines) by its tall neural spines and the form of its crest. The neural spines, which project from the top of the vertebrae, are 5 to 7 times the height of the body of their respective vertebrae in the back, which would have given it a tall back in profile.
Two Medicine Formation
The Two Medicine Formation was deposited in the Late Cretaceous (approximately 75 million years ago) of central Montana, and is known for its relative abundance of dinosaur eggs, nests, and baby dinosaurs — all of which are generally rare in the fossil record.
During the cretaceous, the Two Medicine was an upland environment with a semi-arid climate. It also sat close to the Western Interior Seaway. Volcanoes were also present due to volcanic ash being found.
The Two Medicine Formation was a mountainous-prairie dotted with various volcanoes: at least one of which was active. A small waterhole is known in the upper-elevations, where it seems to be quite rocky. The lowlands are more flat and smooth. Seismic-activity is frequent, and many geysers have been known to burst from the ground in the uplands.
The lower-areas were populated by Maiasaura and Einiosaurus who trekked through during the seasons. Daspletosaurus were also found here, and frequently liked to stalk the two herbivores whenever they're out in the open. The upland-areas were home to Orodromeus and Troodon. Quetzalcoatlus are found here too, making nests on volcanic-cliffs where predators can't touch them.