Description and Classification

Priconodon is known almost exclusively from teeth, which makes a complete reconstruction of the dinosaur challenging. However, these teeth are quite distinct and allow paleontologists to classify it as a member of the Nodosauridae family. Nodosaurids were a group of armored dinosaurs, characterized by bodies covered in bony plates called osteoderms, which provided protection from predators. Unlike their relatives, the ankylosaurids (such as Ankylosaurus), nodosaurids like Priconodon did not possess heavy tail clubs. Instead, they often had prominent shoulder spines or large bony plates for defense.

Priconodon was a quadrupedal herbivore, meaning it walked on four legs and ate plants. Based on the size of its teeth, which are among the largest known for any nodosaurid, it is estimated that Priconodon was a relatively large member of its family, possibly reaching lengths of 6 to 8 meters (about 20 to 26 feet). The teeth themselves are cone-shaped with a strong central ridge and numerous smaller ridges, or denticles, running down the sides, giving them a serrated appearance ideal for shredding tough plant material. Priconodon belongs to the group Dinosauria, order Ornithischia, suborder Thyreophora, infraorder Ankylosauria, and family Nodosauridae. Other well-known nodosaurids include Nodosaurus, Sauropelta, and Edmontonia.

Distinguishing Features

Since Priconodon is primarily known from teeth, its most distinguishing features relate to its dental anatomy. It also shared general characteristics with other nodosaurids.

• Teeth are relatively large compared to most other nodosaurids.
• Tooth crowns are conical (cone-shaped).
• Each tooth has a prominent primary ridge (carina) down the center of the crown.
• Multiple smaller ridges (denticles or secondary carinae) run along the sides of the crown, creating serrated, saw-like cutting edges.
• A distinct cingulum, which is a swollen ridge or collar of enamel, is present at the base of the tooth crown.
• As a nodosaurid, Priconodon would have possessed a body covered in bony armor plates (osteoderms) for protection.
• It likely had spikes or large plates on its shoulders, a common defensive feature in nodosaurids.
• Unlike ankylosaurids, Priconodon would not have had a bony club at the end of its tail.

Paleoenvironment and Diet

Fossils of Priconodon have been discovered in the Arundel Clay formation of Maryland, USA. During the Early Cretaceous period, this region was a coastal plain with a warm, humid climate. The environment consisted of extensive river systems, swamps, floodplains, and forests. This lush habitat supported a diverse range of plant life, which would have formed the diet of Priconodon.

As a herbivore, Priconodon used its specialized teeth to process tough vegetation. It likely fed on low-growing plants such as ferns, cycads, and possibly early forms of flowering plants. Priconodon shared its environment with other dinosaurs, including the large sauropod Astrodon, various ornithopod dinosaurs, and large theropod predators whose teeth (sometimes attributed to relatives of Acrocanthosaurus) have also been found in the Arundel Clay.

Significance and Ongoing Research

Priconodon holds significance as one of the dinosaur genera identified from the Early Cretaceous of eastern North America, providing valuable information about the dinosaur fauna of this region and time period. The large size of its teeth suggests it was a robust and substantial herbivore within its ecosystem. Although known from limited fossil material (primarily teeth), the unique characteristics of these teeth have allowed paleontologists, such as Kenneth Carpenter, to argue for its validity as a distinct genus, despite some earlier suggestions that it might be a nomen dubium (a doubtful name).

Ongoing research ideally hopes for the discovery of more complete skeletal remains of Priconodon. Such finds would greatly enhance our understanding of its full anatomy, exact size, and its precise evolutionary relationships within the Nodosauridae family. Studying Priconodon helps paleontologists piece together the diversity of armored dinosaurs and their adaptations, particularly concerning their feeding mechanisms and how they coexisted with other dinosaurs in the Early Cretaceous ecosystems of North America.