Thursday, December 4, 2014

Discovery of a Dinosaur


Fig.1. Pentaceratops aquilonius, a newly discovered species and a smaller, five-horned cousin of the Triceratops (Credit: Nick Longrich, University of Bath).

The recent release of the Jurassic World trailer has many fans excited and some scientists up in arms. Although our understanding of paleontology has certainly advanced since the original Jurassic Park in 1993, the new trailer raised a few eyebrows with it’s scaly, oversized dinosaurs and other scientific inaccuracies. Luckily, a new paleontological discovery has brought a more realistic view of the ancient world to the forefront of science. Dr. Nick Longrich, a researcher at the University of Bath, discovered a new dinosaur hidden among the collections at the Canadian Museum of Nature in Ottawa. This specimen dates to the Late Cretaceous epoch -- about 70 million years after the end of the Jurassic period -- and provides an important insight into a very old world.

Old bones, new findings

Longrich’s examination of a skull and other fossilized bones in Canada led to some surprising results. These fossils, which had been stored for more than 75 years, were originally thought to belong to the dinosaur genera Anchiceratops and Chasmosaurus. These relatives of the Triceratops roamed Canada during the Late Cretaceous, about 75 million years ago. Upon closer examination, Longrich found that the skeletons more closely resembled fossils from the southwestern United States and were probably new species.

He believed that one set of fossils was related to the New Mexican Pentaceratops sternbergii, and the other could be related to Kosmoceratops from Utah. Both are members of the Triceratops subfamily Chasmosaurinae. Although the latter needs more identification work, Longrich named the first set of fossilized bones Pentaceratops aquilonius. This five-horned, buffalo-sized herbivore had slight but important morphological variation. The shape of the frill and arrangement of hornlets on the back differed enough for Longrich to classify the remains as part of a new species.

 

Clues in a museum

His research went to further examine the ecosystem in which these ancient animals lived. Unlike modern large mammals with mostly large geographic ranges, Longrich found that these dinosaurs were very regional and remained in specific habitats with distinct north and south divisions. He believed that interspecific competition between the diverse and populous Chasmosaurinae members would prevent dinosaurs species from moving between regions. These patterns, Longrich proposed, may explain why paleontologists continually find more species as they sample different habitats. New collections may ultimately hold the key for understanding the diverse Cretaceous ecosystems and animal movement across the continent.

Although there is still much to find underneath our soil, museums are a unique and rich source of discoveries. The discovery of Pentaceratops aquilonius within museum collections shows the importance of preserving specimens for future study. In addition to maintaining a good specimen for morphological or genetic studies, a good collection record allows researchers to return to a site and analyze for more fossils or study the ancient environment.

Longrich’s research was both a detailed examination of skeletal characteristics and an analysis of the larger ecological pattern. He was able to use fossil collections to create a possible geography for a group of animals 75 million years ago. This biologically diverse period in history is reflected in fossils, from freshwater fish and amphibians to many types of dinosaurs, and even that may be an understatement. 

“We thought we had discovered most of the species,” Longrich said in a statement to the press, “but it seems there are many undiscovered dinosaurs left. There are lots of species out there. We've really only just scratched the surface.”


References:

Longrich, N.R. (2014, September). The horned dinosaurs Pentaceratops and Kosmoceratops from the upper Campanian of Alberta and implications for dinosaur biogeography. Cretaceous Research, 51: 292-308. doi: http://dx.doi.org/10.1016/j.cretres.2014.06.011

University of Bath. (2014). New species of dinosaur discovered lying forgotten in a museum [Press release]. Retrieved from http://www.bath.ac.uk/research/news/2014/11/26/new-dinosaur-discovered?utm_content=buffer4a715&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer.



Glossary

Late Cretaceous epoch
The more recent of two epochs into which the Cretaceous period is divided in the geologic timescale, ranging 100 to 66 million years ago.
Jurassic period
A geologic period that lasted from 201 to 145 million years ago (end of Triassic period to beginning of Cretaceous period)
interspecific competition
A form of competition in ecology in which individuals of different species compete for the same resources in an ecosystem
subfamily
A biological classification of organisms which is smaller than a family but more inclusive than genus.

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