An article published in the “Canadian Journal of Earth Sciences” describes a research on Ceratopsids, the so called horned dinosaurs that lived in the Late Cretaceous in today’s western areas of North America. A group of researchers led by Dr. Michael Ryan of the Cleveland Museum of Natural History, included some species into two new groups, or clades in technical jargon, called Nasutoceratopsini and Centrosaurini (Centrosaurinae).
Ceratopsids – family Ceratopsidae – were herbivorous dinosaurs recognizable for the head shield in the back area of the skull and for their horns, which could be from one to three. The shields could be used as a defensive weapon against predators or as ornaments, perhaps to attract mates. Among the various species discovered in the course of time, some show strong horns and shields while others show shields that seem too fragile to have a practical use so it’s likely that their use would vary depending on the species.
In the Late Cretaceous, between 99 and 66 million years ago, in today’s North America there were many species of horned dinosaurs. The Triceratops is the most famous but over the years several others have been found. As often it happens in the field of paleontology, in many cases a species is known only through a partial skeleton, with the consequent problems of classification.
Among the elements used for the classification of Ceratopsids there are the size and shape of their shields and horns of the various species. Nasutoceratopsini had wide shields without well developed ornaments, suggesting that they blended into their environment. Instead, Centrosaurini had shields that were very rich from an ornamental point of view.
The clade Centrosaurini includes the genera: Centrosaurus, Coronosaurus, Rubeosaurus, Spinops and Styracosaurus, which lived mostly in today’s state of Alberta, Canada, and in some areas of the today’s USA. The clade Nasutoceratopsini includes the genera Avaceratops and Nasutoceratops, which lived in today’s states of Montana and Utah.
The species included in the two new clades were discovered during more than a century of paleontological research. The Cleveland Museum of Natural History works with the Southern Alberta Dinosaur Project (SADP), which aims to study the Late Cretaceous fauna in the Canadian state of Alberta. The new classification that led to the creation of the two new clades is part of the project and aims to better study these horned dinosaurs’ evolution.
There are other projects that aim to study dinosaurs but also other prehistoric animals in various areas of the world. Research such as this one, focused on the classification of various groups of animals, help to shed light on their relations and their evolution.
