Styracosaurus

Styracosaurus ("spiked lizard" ) was a ceratopsian dinosaur from the Late Cretaceous Period. It was distinguished by having a large, horned neck frill and one large horn on its nose.

Description
Styracosaurus was about 5.5 meters long and weighed approximately 2.7 tons. Its most distinctive feature was its head, which was large and had a neck frill adorned with a number of horns, from which the dinosaur gets its name. These spikes can be more than 50 centimeters long. The nose horn was usually even longer. As with most ceratopsians, Styracosaurus had a smaller horn on each cheek.

The limb positions of Styracosaurus and other ceratopsians is uncertain, and both upright and sprawling positions have been proposed. Current research suggests it was somewhere in between these two extremes.

Classification
Styracosaurus was part of the ceratopsian subfamily Centrosaurinae, which is distinguished by prominent nose horns and subordinate brow horns, among others. Because centrosaurine classification is often based solely upon head ornamentation, determining species is difficult, and even differences among skulls could possibly be attributed to sexual dimorphism. In fact, one species of Styracosaurus, S. ovatus, was placed into a new genus, Rubeosaurus, in 2010. Currently, only the type species of Styracosaurus, S. albertensis, is valid.

Below is a 2011 cladogram that shows the position of Styracosaurus within the Centrosaurinae:

Discovery
Styracosaurus was first discovered by the fossil hunter Charles M. Sternberg in what is now Dinosaur Provincial Park in Alberta, Canada. S. albertensis was named by Lawrence Lambe in 1913.

Two years later, the paleontologist Barnum Brown discovered a second skeleton in the same formation. He compared it to the holotype and found it different enough to erect a new species for his find, S. parksi, after the paleontologist William Parks. However, it is now considered to be another specimen of S. albertensis. The skeleton is still on display in the American Museum of Natural History.

Charles Gilmore described another species of Styracosaurus, S. ovatus, in 1930 from the Two Medicine Formation of Montana. The fossil material was incomplete, but it seemed to have shorter horns than S. albertensis. In 2010, Andrew McDonald and Jack Horner reassigned the species to its own genus, Rubeosaurus.

Paleobiology
Styracosaurus is often considered to be a herd animal, which is supported by fossil evidence. A bonebed of the dinosaur exists in the Dinosaur Park Formation, which lies in a river deposit. There are many hypotheses as to how and why the animals gathered here.

Greg Paul and Per Christiansen have suggested that large ceratopsians like Styracosaurus could run faster than an elephant at times, based on evidence from trackways.

Diet
Like its relatives, Styracosaurus was probably herbivorous, although it has been suggested that some ceratopsians were at least partially omnivorous. Its jaws bore a deep, narrow beak that was probably better suited to grabbing or plucking than biting. Unlike those of hadrosaurids, ceratopsid teeth sliced but did not grind.

Ornamentation
The horns and frill of Styracosaurus makes it one of the most distinctive of dinosaurs, and several hypotheses for their purpose have been proposed. In 1908 R. S. Lull proposed that the giant frills of ceratopsians were used to anchor large jaw muscles, a theory that, although once supported, has now been mostly abandoned.

One of the most popular theories was that the horns of Styracosaurus and other ceratopsians were used to defend themselves from predators, while the frill protected the vulnerable area of the neck. The horns could also be used in combat with other members of the species. Scratches and pitting found on ceratopsian skulls seemed to support these ideas. However, in 2006, a study attributed these scratches to bone resorption or disease. Even, there is still valid evidence supporting intra-species combat in at least some types of ceratopsian.

At the current time, the most widely accepted theory for the purpose of ceratopsian ornamentation is for sexual display. This explains the fact that the horns and frill of different species of ceratopsian varied widely in size, shape, and placement. Modern animals that exhibit such adornment also use them for display purposes, strengthening this theory.

In popular culture
Because of its distinctive horns and frill, Styracosaurus is one of the most recognizable dinosaurs, and is one of the more famous ceratopsians after Triceratops. It has appeared in various films such as The Valley of Gwangi, where a Styracosaurus fights the Allosaurus title character; The Land That Time Forgot, and the Disney film Dinosaur. Styracosaurus is also mentioned in the first Jurassic Park novel, although it is never seen. The animal makes several appearances in games and television series.