evolutionary lineage that eventually developed into Stellasaurus, Achelousaurus, and Pachyrhinosaurus. Paleobiology Styracosaurus and other horned dinosaurs are often depicted in popular culture as herd animals. A bonebed composed of Styracosaurus remains is known from the Dinosaur Park Formation of Alberta, about halfway up the formation. This bonebed is associated with different types of river deposits. The mass deaths may have been a result of otherwise non-herding animals congregating around a waterhole in a period of drought, with evidence suggesting the environment may have been seasonal and semi-arid. Paleontologists Gregory Paul and Per Christiansen proposed that large ceratopsians such as Styracosaurus were able to run faster than an elephant, based on possible ceratopsian trackways which did not exhibit signs of sprawling forelimbs. Dentition and diet Styracosaurs were herbivorous dinosaurs; they probably fed mostly on low growth because of the position of the head. They may, however, have been able to knock down taller plants with their horns, beak, and bulk. The jaws were tipped with a deep, narrow beak, believed to have been better at grasping and plucking than biting. Ceratopsid teeth, including those of Styracosaurus, were arranged in groups called batteries. Older teeth on top were continually replaced by the teeth underneath them. Unlike hadrosaurids, which also had dental batteries, ceratopsid teeth sliced but did not grind. Some scientists have suggested that ceratopsids like Styracosaurus ate palms and cycads, while others have suggested ferns. Dodson has proposed that Late Cretaceous ceratopsians may have knocked down angiosperm trees and then sheared off leaves and twigs. Horns and frill The large nasal horns and frills of Styracosaurus are among the most distinctive facial adornments of all dinosaurs. Their function has been the subject of debate since the first horned dinosaurs were discovered. Early in the 20th century, paleontologist R. S. Lull proposed that the frills of ceratopsian dinosaurs acted as anchor points for their jaw muscles. He later noted that for Styracosaurus, the spikes would have given it a formidable appearance. In 1996, Dodson supported the idea of muscle attachments in part and created detailed diagrams of possible muscle attachments in the frills of Styracosaurus and Chasmosaurus, but did not subscribe to the idea that they completely filled in the fenestrae. C. A. Forster, however, found no evidence of large muscle attachments on the frill bones. It was long believed that ceratopsians like Styracosaurus used their frills and horns in defence against