Residents at the Rocky Mountain Dinosaur Resource Center

During the Late Cretaceous period, a wide range of dinosaurs, prehistoric creatures and marine animals inhabited the Earth. In this article, you will encounter some of the specimens on display at the Rocky Mountain Dinosaur Resource Center, including the Denversaurus.

Denversaurus (Edmontonia) cf. schlessmani

Nicknamed ‘Tank,’ the Rocky Mountain Dinosaur Resource Center is home to a Denversaurus ”“ a large armored dinosaur that belongs to the Nodosaur family. Discovered in Niobrara County, Wyoming, the specimen first found a place to stay in Okayama, Japan at the Hayashibara Museum of Natural Sciences before coming to the Center. The Denversaurus lived during the Late Cretaceous period, which was 66 million years ago. The species was a herbivore, meaning that it only ate plants as part of its diet.

The dinosaur typically dwelled in subtropical fauna surroundings of the deltas of the Western Interior Seaway. Finding an example of the dinosaur is quite rare so the cast on display was made from the most complete skeleton that researchers have ever found. Visitors will be able to view a nearly complete skull and more than 100 preserved dermal plates.


It was 83 million years ago during the Late Cretaceous period that the Ichthyodectes took to the waters of the Western Interior Seaway in search for prey. The carnivorous, large fish (measuring 6 feet long) ate a diet that consisted of smaller fish. After being discovered in Western Kansas, the specimen was brought to the Rocky Mountain Dinosaur Resource Center. The Ichthyodectes was related to a larger cousin called the Xiphactinus. Medium-sized teeth filled the mouth of the Ichthyodectes, which decorated it throughout the jaw.

The major muscles of the fish were attached to the bony top of the head in what was called the supraoccipital. Early researchers believed that the fish had a spike or horn attached to the head, but it was not the case. Not much is known about the fish, but it was most likely a meal for sharks as seen in previous specimens.

Pachyrhizodus caninus

In 1993, Mike Triebold uncovered the Pachyrhizodus caninus specimen in Lane County, Kansas, where it was first taken to the North American Museum of Ancient Life in Lehi, Utah before making its way to the Center. The giant predatory fish lived about the waters in the North America inland seas during the Late Cretaceous period ”“ dating back 84 million years. The original specimen was nearly complete with a good structure to make a 3-D display. When the skull was reproduced, you will not the intricate details, including gill arches and hyoid apparatus.

This species of fish were predators in the waters, but also fell victim to some of the larger fish of prehistoric times. For example, the first specimen of this type of fish was found inside of a larger fish.