Hadrosaur Dorsal Vertebra | Judith River Formation | Montana

Hadrosaur sp. (Brachylophosaurus?)
Late Cretaceous (~74 MYO)
Judith River Formation
Montana, USA

Specimen approx. size: 11" x 5" x 5.75"

The vertebral fractures are a result of geologic processes, which have been remedied through the use of glue for stabilization.

Hadrosaurs, often called "duck-billed dinosaurs," are a family of ornithopod dinosaurs (family Hadrosauridae) that thrived during the Late Cretaceous period. They are among the most well-known and successful herbivorous dinosaurs.

Hadrosaurs are characterized by:

• Broad, flattened rostrums (beak-like snouts) resembling a modern duck’s bill, used for cropping vegetation.

• Hundreds of tightly packed teeth forming a dental battery, ideal for grinding tough, fibrous plant material.

• Large, barrel-shaped torsos and relatively long, muscular tails, likely used for balance.

• Bipedal and quadrupedal locomotion. They could walk both on two legs (especially for faster movement) and on four (likely while grazing).

• Most hadrosaurs ranged from 7–10 meters (23–33 feet) in length, though some, like Shantungosaurus, reached over 15 meters (50 feet).

Hadrosauridae is split into two main subgroups:

• Saurolophines: Generally had solid crests or none at all (e.g., Edmontosaurus, Saurolophus).

• Lambeosaurines: Noted for their elaborate, hollow cranial crests (e.g., Corythosaurus, Parasaurolophus), possibly used for vocalization, display, or species recognition.

Hadrosaurs were highly adaptable and occupied a variety of environments, from coastal plains to inland floodplains. Their complex teeth and jaw structures allowed them to process a wide variety of plants, including conifers, ferns, and flowering plants. Fossil trackways and bonebeds suggest they lived in herds, possibly migrating seasonally.