Agujaceratops (ah-GOO-hah-SEH-rah-tops; “Agua horn-face”) is a genus of chasmosaurine ceratopsid dinosaur that lived during the Late Cretaceous period, approximately 77 million years ago. Its fossils were discovered in the Aguja Formation in Texas, USA, which is how it got its name. Agujaceratops was first identified as a distinct genus in 2006 by paleontologists Spencer G. Lucas, Robert M. Sullivan, and Adrian Hunt. Before that, its remains were often thought to belong to another horned dinosaur, Chasmosaurus.
Description and Classification
Agujaceratops was a four-legged, plant-eating dinosaur, typical of the ceratopsian group. It was a medium-sized horned dinosaur, estimated to be about 4.5 to 5 meters (15 to 16 feet) long and weighing around 1.5 to 2 metric tons (1.7 to 2.2 short tons). Like its relatives, Agujaceratops had a prominent bony frill at the back of its skull and horns. It featured two long brow horns above its eyes and possibly a smaller horn or a bony bump on its nose. The frill of Agujaceratops was relatively short and broad for a chasmosaurine, and it had large openings in it, called parietal fenestrae, which helped to reduce the skull’s overall weight.
Agujaceratops belongs to the family Ceratopsidae, which includes other well-known horned dinosaurs like Triceratops. Within this family, it is classified under the subfamily Chasmosaurinae. Chasmosaurines are generally known for having longer frills and more prominent brow horns compared to another group called Centrosaurinae. The existence of Agujaceratops shows how diverse horned dinosaurs were in the southern part of ancient North America.
Distinguishing Features
Agujaceratops can be recognized by several key characteristics that set it apart from other ceratopsid dinosaurs:
- It had long brow horns that typically curved forward or slightly backward over its eyes.
- The neck frill was relatively short but wide for a chasmosaurine, characterized by large openings (fenestrae).
- A noticeable notch or indentation was present at the top-middle edge of its frill.
- The edge of the frill was adorned with a series of small, bony bumps called epoccipitals, giving it a somewhat scalloped look.
- While not always clearly preserved, it likely had a small, low nose horn or a roughened bony area on its snout.
Paleoenvironment and Diet
Fossils of Agujaceratops have been found in the Aguja Formation, located in what is now Big Bend National Park, Texas. During the Late Cretaceous period, this region was a warm and humid coastal plain. It featured extensive river systems, swamps, and deltas close to the edge of the Western Interior Seaway, an ancient sea that once divided North America. This environment supported a rich array of plant life, which formed the primary food source for Agujaceratops. As an herbivore, it likely fed on low-growing plants such as ferns, cycads, and early types of flowering plants. It would have used its strong, beak-like mouth to snip off vegetation and its batteries of teeth to grind the tough plant material.
Agujaceratops shared its habitat with a variety of other prehistoric animals. These included other dinosaurs like the hadrosaur Kritosaurus, other ceratopsians, armored ankylosaurs, and predatory theropods such as tyrannosaurids. The ecosystem was also home to crocodiles, turtles, and various types of fish, indicating a vibrant and complex food web.
Significance and Ongoing Research
The study of Agujaceratops is important for understanding the diversity and evolution of horned dinosaurs, especially those that lived in the southern part of Laramidia (the western landmass of North America during the Late Cretaceous). It helps paleontologists trace how different groups of chasmosaurines spread out and developed. For some time, paleontologists debated whether Agujaceratops was truly its own genus or just a species of Chasmosaurus. However, most researchers now agree that Agujaceratops is a distinct and valid type of horned dinosaur.
Ongoing research aims to further understand the anatomy of Agujaceratops, its precise position within the Ceratopsidae family tree, and the specific role it played in its ancient ecosystem. Future fossil discoveries in the Aguja Formation could reveal more complete skeletons, offering more insights into its growth, behavior, and any variations within the species. By comparing Agujaceratops with other chasmosaurine dinosaurs from different areas, scientists can build a more complete picture of dinosaur life and evolution during this fascinating period in Earth’s history.