Nav: Home

Chewing versus sex in the duck-billed dinosaurs

May 02, 2019

The duck-billed hadrosaurs walked the Earth over 90-million years ago and were one of the most successful groups of dinosaurs. But why were these 2-3 tonne giants so successful? A new study, published in Paleobiology, shows that their special adaptations in teeth and jaws and in their head crests were crucial, and provides new insights into how these innovations evolved.

Called the 'sheep of the Mesozoic'as they filled the landscape in the Late Cretaceous period, hadrosaurs walked on their hind legs and were known for their powerful jaws with multiple rows of extremely effective teeth. They also had hugely varied head display crests that signalled which species each belonged to and were used to attract mates. Some even trumpeted and tooted their special call, using nasal passages through the head crests.

Researchers from the Universities of Bristol and the Catalan Institute of Paleontology in Barcelona used a large database describing morphological variety in hadrosaur fossils and computational methods that quantify morphological variety and the pace of evolution.

Dr Tom Stubbs, lead author of the study and a researcher from Bristol's School of Earth Sciences, said: "Our study shows that the unique hadrosaur feeding apparatus evolved fast in a single burst, and once established, showed very little change. In comparison, the elaborate display crests kept diversifying in several bursts of evolution, giving rise to the many weird and wonderful shapes."

Professor Mike Benton, the study's co-author from Bristol's School of Earth Sciences, added, "Variation in anatomy can arise in many ways. We wanted to compare the two famous hadrosaur innovations, and by doing so, provide new insights into the evolution of this important dinosaur group. New numerical methods allow us to test these kinds of complex evolutionary hypotheses."

"Our methods allowed us to identify branches on the hadrosaur evolutionary tree that showed rapid evolution in different parts of the skeleton," said co-author Dr Armin Elsler. "When we looked at the jaws and teeth, we only saw fast evolution on a single branch at the base of the group. On the other hand, the bones that form the display crests showed multiple fast rate branches."

Dr Albert Prieto-Márquez, co-author and world-leading expert on hadrosaurs from the Catalan Institute of Paleontology in Barcelona, added: "Our results suggest that evolution can be driven in different ways by natural selection and sexual selection. Hadrosaurs apparently fixed on a feeding apparatus that was successful and did not require massive modification to process their food. On the other hand, sexual selection drove the evolution of more complex crest shapes, and this is reflected by multiple evolutionary bursts."
-end-
Paper

'Morphological innovation and the evolution of hadrosaurid dinosaurs' by Stubbs, T. L, Benton, M.J, Elsler, A, and Prieto-Márquez, A, in Paleobiology

University of Bristol

Related Evolution Articles:

Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
More Evolution News and Evolution Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...