Hadrosauridae

Trachodon mirabilis

Corythosaurus snorkel

Maiasaurusnest

Figure 6. Hadrosaurs of North America, exemplified by the selection of skulls of valid nominal genera

Eotrachodon maxilla

Hadrosauridae is a family of dinosaurs known as duck-billed dinosaurs, due to their characteristic flat, duck-bill appearance of the skulls. These herbivorous dinosaurs are part of the Ornithischia clade and lived during the Late Cretaceous period, approximately 90 to 66 million years ago. The Hadrosauridae family is divided into two main subfamilies: the Lambeosaurinae, which had hollow cranial crests or tubes, and the Saurolophinae (previously known as Hadrosaurinae), which had solid crests or no crests at all.

Description

Hadrosaurids were large dinosaurs, with some species reaching up to 15 meters (49 feet) in length. They were primarily bipedal but could also walk on all fours, especially while feeding. Their forelimbs were much shorter than their hind limbs, but were strong and capable of supporting their weight. The most distinctive feature of hadrosaurids was their skulls, which were highly modified with a broad, flat beak used for cropping vegetation. Their teeth were arranged in complex batteries with hundreds of teeth at any given time, well-suited for chewing tough, fibrous plant material.

Classification

The classification of Hadrosauridae has evolved over time, with current taxonomy recognizing two main subfamilies:

• Lambeosaurinae: Characterized by their hollow cranial crests, which may have been used for communication, display, or olfactory enhancement. Genera include Lambeosaurus, Corythosaurus, and Parasaurolophus.
• Saurolophinae: This group includes species with solid crests or no crests at all. Notable genera include Saurolophus, Edmontosaurus, and Shantungosaurus.

Distribution and Habitat

Hadrosaurids were widespread across what is now North America, Asia, and Europe. They inhabited a variety of environments, from coastal plains to forested areas, indicating their adaptability and generalist feeding habits.

Paleobiology

The paleobiology of hadrosaurids is well-understood thanks to numerous fossil finds, including well-preserved specimens that offer insights into their diet, social behavior, and growth patterns. Evidence suggests that hadrosaurids lived in large, social groups and had complex behaviors, including potentially migratory patterns. Their teeth and jaw structure indicate a diet of tough, fibrous plants, and their coprolites (fossilized feces) have shown evidence of wood particles, suggesting they could digest a wide range of plant material.

Extinction

Hadrosauridae, along with all other non-avian dinosaurs, went extinct during the Cretaceous-Paleogene extinction event approximately 66 million years ago. This mass extinction event is widely attributed to a combination of volcanic activity, climate change, and the impact of a large asteroid or comet.

In Popular Culture

Hadrosaurids have been featured in various forms of popular culture, including movies, television shows, and literature. Their distinctive appearance and social behavior make them a favorite among dinosaur enthusiasts.