Mark Purnell
Encyclopedia
Dr Mark Andrew Purnell is a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 palaeontologist, Reader of Geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 at the University of Leicester
University of Leicester
The University of Leicester is a research-led university based in Leicester, England. The main campus is a mile south of the city centre, adjacent to Victoria Park and Wyggeston and Queen Elizabeth I College....

.

Purnell is an expert in conodont
Conodont
Conodonts are extinct chordates resembling eels, classified in the class Conodonta. For many years, they were known only from tooth-like microfossils now called conodont elements, found in isolation. Knowledge about soft tissues remains relatively sparse to this day...

 biostratigraphy
Biostratigraphy
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period...

 (principally Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

) and conodont palaeobiology
Paleobiology
Paleobiology is a growing and comparatively new discipline which combines the methods and findings of the natural science biology with the methods and findings of the earth science paleontology...

, focussing especially on attempts to uncover the function of conodont
Conodont
Conodonts are extinct chordates resembling eels, classified in the class Conodonta. For many years, they were known only from tooth-like microfossils now called conodont elements, found in isolation. Knowledge about soft tissues remains relatively sparse to this day...

 elements. Using conventional functional morphology, physical modelling and microwear  analysis, Purnell uncovered unequivocal evidence that conodont elements had performed a mechanical tooth function in life, resolving a palaeobiological debate that had run for more than a century. His work has expanded in recent years to analysing feeding mechanisms of extinct vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

s more generally, exploiting microwear, including validation studies based on extant stickleback
Stickleback
The Gasterosteidae are a family of fish including the sticklebacks. FishBase currently recognises sixteen species in the family, grouped in five genera. However several of the species have a number of recognised subspecies, and the taxonomy of the family is thought to be in need of revision...

 fish.

Purnell was awarded the Hinde Medal of the Pander society
Pander society
The Pander Society is an informal organisation based in the founded in 1967 for the promotion of the study of conodont palaeontology. It publishes an annual newsletter...

 in 2006 and served as Vice-President of the Palaeontological Association
Palaeontological Association
The Palaeontological Association is a charitable organisation based in the UK founded in 1957 for the promotion of the study of palaeontology.-Functions:...

 from 2003-2005.

In 2009, Purnell conducted a study into the chewing methods and diet of hadrosaurid
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...

s, a herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 species of duck-billed dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s from the Late Cretaceous period
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

. The study, which Purnell co-authored with paleontologist Paul Barrett and graduate student Vince Williams, was published on June 30, 2009 in the journal, The Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences
The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences...

. By analyzing hundreds of microscopic scratches on the teeth of a fossilized Edmontosaurus
Edmontosaurus
Edmontosaurus is a genus of crestless hadrosaurid dinosaur. It contains two species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian stage of the Cretaceous Period 73 million years ago,...

jaw, the team determined hadrosaurs had a unique way of eating unlike any creature living today. In contrast to a flexible lower jaw joint prevalent in today's mammals, hadrosaurs had a unique hinge between the upper jaws and the rest of its skull. The team found the dinosaur's upper jaws pushed outwards and sideways while chewing, as the lower jaw slid against the upper teeth. The study also found that hadrosaurs likely grazed on horsetails and vegetation close to the ground, rather than browsing higher-growing leaves and twigs. However, Purnell said these conclusions were less secure than the more conclusive evidence regarding the motion of teeth while chewing.
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