Dino jaws: Stegosaurs bite strength revealed

The Natural History Museum’s Stegosaurus specimen, ‘Sophie’, has been compared with two plant-eating dinosaurs with similar skulls: Plateosaurus and Erlikosaurus.

All three had a large low snout and a scissor-like jaw action that moved up and down. Using computer modelling a team of scientists from Bristol, London, Manchester and Birmingham has shown these dinosaurs had different biting abilities.

As Prof Paul Barrett, dinosaur researcher at the Natural History Museum explains: 'Far from being feeble, as usually thought, Stegosaurus actually had a bite force within the range of living herbivorous mammals, such as sheep and cows.'

The finding means that scientists need to reconsider how Stegosaurus fitted into its ecological niche. For example it may have had a role in spreading the seeds of woody evergreen cycads.

Stegosaurus lived around 150 million years ago and needed to eat a lot of plants to sustain its large size. As grasses did not exist then, it would have fed on plants such as ferns and horsetails.

As Barrett, leader of the research team, comments: “Our key finding really surprised us: we expected that many of these dinosaur herbivores would have skulls that worked in broadly similar ways. Instead we found that even though the skulls were fairly similar to each other in overall shape, the way they worked during biting was substantially different in each case.”

Lead author Dr Stephan Lautenschlager, a post-doctoral researcher at the University of Bristol’s School of Earth Sciences, employed digital models and computer simulations to analyse the dinosaurs’ bites, using data from 3D scans of the skulls and lower jaws. He used engineering software to give the skulls the material properties that would match as closely as possible to the real thing, for example, using data on crocodile teeth to model those of the dinosaurs.

By attaching muscles to the models, he was able to examine the forces that the jaws could produce and the subsequent stresses on the skulls.

As computer power increases and software becomes more available, Lautenschlager thinks that we will see more modelling used in dinosaur research: 'Using computer modelling techniques, we were able to reconstruct muscle and bite forces very accurately for the different dinosaurs in our study. As a result, these methods give us new and detailed insights into dinosaur biology – something that would not have been possible several years ago.'

The Stegosaurus is part of the Museum’s collection of 80 million specimens, of which eight million are fossils. We are extremely grateful to the 70 generous donors, with particular thanks to Jeremy Herrmann, who made this iconic acquisition possible. Stegosaurs stenops has been named Sophie in honour of Jeremy’s daughter Sophie Herrmann.

Notes for editors

Further images are available at https://nhm.box.com/s/fnaf66vdo8bbrekfilwu3b7di8q327zf
Please note: images are for single use only to illustrate this press release and are not to be archived. All images © Stephan Lautenschlager

Original Publication
Lautenschlager, S., Brassey, C. A., Button, D. J., Barrett, P. M. Decoupled form and function in disparate herbivorous dinosaur clades. Sci. Rep. 6, 26495; doi:10.1038/srep26495 (2016)   http://www.nature.com/articles/srep26495

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