Coronosaurus

Coronosaurus is a genus of centrosaurine ceratopsian dinosaurs that roamed the Earth during the Late Cretaceous period, specifically in the middle Campanian stage. Its fossil remains, consisting of two significant bone beds, were unearthed in the Oldman Formation of Alberta, Canada. The genus and its sole species, Coronosaurus brinkmani, were initially described in 2005 as a new species within the genus Centrosaurus, but later studies led to its establishment as a separate genus in 2012.

Discovery and Naming

The discovery of Coronosaurus is credited to Phillip J. Currie, who excavated the fossil material between 1996 and 2000. The type species, Centrosaurus brinkmani, was formally named and described by Michael J. Ryan and Anthony P. Russell in 2005. However, subsequent phylogenetic analyses questioned its close relationship with the type species of Centrosaurus. Consequently, in 2012, Ryan, David C. Evans, and Kieran M. Shepherd erected the new genus Coronosaurus to accommodate the species. The generic name, Coronosaurus, is derived from the Latin word "corona" meaning "crown" and the Greek word "sauros" meaning "lizard." This name aptly describes the distinctive, crown-like ornamentation on the dinosaur's frill. The species name, brinkmani, honors Donald Brinkman for his contributions to the palaeoecology of Late Cretaceous Alberta. A more informal, humorous nickname used by fellow students was ‘broccoli-ceratops’.

Description and Physical Characteristics

Coronosaurus was a medium-sized ceratopsid, with estimates placing its adult body length at approximately 5 meters (16 ft) and its weight around 2 tonnes (2.2 short tons). Like other ceratopsians, it possessed a prominent frill and horns. It featured a pair of relatively small brow horns above its eyes and a large nasal horn on its snout. Uniquely among ceratopsians, Coronosaurus had irregular, spiky bone masses on the posterior margin of its frill, which fused to the bone and gave it a crown-like appearance. These accessory epiparietal ossifications developed through the individual's growth, starting as short spines that could merge into larger masses. The nasal horn of Coronosaurus closely resembles that of Centrosaurus apertus, with a blunt tip formed by fused nasals and generally recurved anterior and posterior margins.

Classification and Paleoecology

Coronosaurus is classified as a member of the Centrosaurini tribe, a group of derived centrosaurine ceratopsians that also includes genera like Styracosaurus, Spinops, Rubeosaurus, and Centrosaurus. Its classification has been a subject of phylogenetic study, with different analyses placing it in varying relationships within the Centrosaurini. The paleoenvironment indicated by the Oldman Formation, where Coronosaurus fossils were found, was an ancient coastal plain. This ecosystem was shared with a variety of other dinosaurs, including theropods such as Saurornitholestes and Daspletosaurus, other ceratopsids like Albertaceratops and Chasmosaurus, and hadrosaurids such as Parasaurolophus and Corythosaurus.