2.1" Maiasaura Hadrosaur Dinosaur Rib Bone Fossil Two Medicine FM Montana COA

Location: Two Medicine Formation, Montana (Private Land Origin)

Weight: 1.4 Ounces 

Dimensions: 2.1 Inches Long, 1.5 Inches Wide, 0.6 Inches Thick 

Comes with a Certificate of Authenticity

The item pictured is the one you will receive.

Cretaceous Age 83-70 Million Years Old.

Name: Maiasaura

Type: Herbivore

Size: 9 meters in length.

Maiasaura was a large herbivorous hadrosaur that lived during the Late Cretaceous period, approximately 65 to 70 million years ago. Known from fossils discovered in the Two Medicine Formation near Choteau, this duck-billed dinosaur has become one of the best-known examples of dinosaur growth and social behavior. Adults reached lengths of around eight meters and weighed close to four metric tons, achieving full size within just seven to eight years.

Its skull featured a short, broad toothless beak used for cropping vegetation, while rows of hundreds of tightly packed teeth allowed efficient grinding of tough plant matter. A small crest between the eyes distinguished its profile, and its long tail helped maintain balance during movement. Maiasaura’s limb proportions suggest flexibility in locomotion, with longer hind limbs allowing both bipedal walking and quadrupedal grazing.

The discovery of extensive nesting sites has suggested that Maiasaura lived in groups and returned to breeding grounds repeatedly, providing important clues about dinosaur social structures and parental behavior during the Late Cretaceous.