Hadrosaurids

By | September 9, 2016

Also known as “duck-billed” dinosaurs, the hadrosaurids were large plant-eaters with distinctive, ducklike bills that they used to clip leaves from plants. Hadrosaurids may have lived in large herds, and some types seem to have formed nesting colonies in which parents nursed their young after hatching.

FAMILY FACT FILE

Key features
■ Ducklike bills
■ Rear of mouth was packed with thousands of teeth for grinding leaves
■ Forelimbs were half as long as hindlimbs
■ Many hadrosaurids had strangely shaped crests on their heads

When
Hadrosaurids lived in the Cretaceous Period, between 100 and 65 million years ago.

FAMILY LIFE

maiasaura-eggs-and-babies

Maiasaura eggs and babies

Fossilized eggshell pieces and young Maiasaura were discovered in nests in Montana. The presence of young animals suggests that hatchlings stayed in the nest while being looked after, just as many baby birds do, rather than leaving immediately as newly hatched turtles and crocodiles do.

Maiasaura (MY-a-SORE-a)

maiasaura


When: 80–74 million years ago (Late Cretaceous)

Fossil location: USA

Habitat: Coastal plains

Length: 30 ft (9 m)

Diet: Leaves

The name Maiasaura means “good mother lizard.” In Montana, scientists found numerous bowl-shaped Maiasaura nests close together. The site may have been a nesting colony where parents raised their young, like nesting colonies of modern seabirds.

Hadrosaurus (HAD-roh-SORE-uss)

hadrosaurus


When: 80–74 million years ago (Late Cretaceous)

Fossil location: N. America

Habitat: Woodlands

Length: 30 ft (9 m)

Diet: Leaves and twigs

This was one of the first dinosaurs discovered in North America. Hadrosaurus used a toothless beak to tear twigs and leaves from plants before grinding them to a pulp with hundreds of tiny teeth located in the back of its mouth.

Brachylophosaurus (BRACK-ee-LOAF-oh-SORE-uss)

brachylophosaurus


When: 75–65 million years ago (Late Cretaceous)

Fossil location: N. America

Habitat: Woodlands

Length: 30 ft (9 m)

Diet: Ferns, magnolias, and conifers

Brachylophosaurus had a deep snout and a rectangular skull with a flat, paddle-shaped crest on its head. Males had wider crests and were more heavily built than females. In 2000, a near-perfect fossil skeleton was found in Montana. Large areas of its body were covered with an impression of its scaly skin.

Parasaurolophus (PA-ra-SORE-oh-LOAF-uss)

parasaurolophus


When: 76–74 million years ago (Late Cretaceous)

Fossil location: N. America

Habitat: Woodlands

Length: 30 ft (9 m)

Diet: Leaves, seeds, and pine needles

This creature’s head had a long, tubelike crest containing hollow tubes. Perhaps Parasaurolophus tooted air out of the crest to make trumpetlike sounds to communicate with herd members. Its heavy, muscular build and wide shoulders may have helped it push through dense undergrowth in woodlands.

Lambeosaurus (LAMB-ee-oh-SORE-uss)

lambeosaurus


When: 76–74 million years ago (Late Cretaceous)

Fossil location: Canada

Habitat: Woodlands

Length: 30 ft (9 m)

■ Diet Low-growing leaves, fruits, and seeds

Lambeosaurus’s hollow crest was shaped like a hatchet. Perhaps the distinctive shape enabled this dinosaur to recognize others of its species quickly. The crest’s shape varied between the sexes, suggesting that males used theirs to impress females.

Gryposaurus (GRIP-o-SAWR-us)

gryposaurus-skeleton

Gryposaurus skeleton

When: 65–85 million years ago (Late Cretaceous)

Fossil location: N. America

Habitat: Woodlands

Length: 30 ft (9 m)

Diet: Vegetation

Gryposaurus’s large, hooked nose looked like a rounded beak. Rivals may have settled contests by butting noses and shoving each other. Gryposaurus also had very long arms for a hadrosaurid—perhaps they helped it reach higher leaves. Skin impressions suggest the animal had pyramid-shaped scales on its back.

Save

Save

Leave a Reply

Your email address will not be published. Required fields are marked *