Featured Research

from universities, journals, and other organizations

Duck-bill dinosaurs had plant-pulverizing teeth more advanced than horses

Date:
October 4, 2012
Source:
American Museum of Natural History
Summary:
A team of paleontologists and engineers has found that duck-billed dinosaurs had an amazing capacity to chew tough and abrasive plants with grinding teeth more complex than those of cows, horses, and other well-known modern grazers. Their study is the first to recover material properties from fossilized teeth.

This cross-section of a duck-billed dinosaur tooth (Edmontosaurus) shows the remarkably complex architecture. Six main tissues compose the tooth, where most reptiles only have two (enamel and orthodentine). Like horse, bison, and elephant teeth, the myriad of tissues--each with their own unique wear attributes--allowed the teeth to self-wear with use to form complex grinding surfaces. These dinosaurs possessed among the most sophisticated teeth known.
Credit: G. M. Erickson/Florida State University

A team of paleontologists and engineers has found that duck-billed dinosaurs had an amazing capacity to chew tough and abrasive plants with grinding teeth more complex than those of cows, horses, and other well-known modern grazers. Their study, which is published October 4 in the journal Science, is the first to recover material properties from fossilized teeth.

Related Articles


Duck-bill dinosaurs, also known as hadrosaurids, were the dominant plant-eaters in what are now Europe, North America, and Asia during the Late Cretaceous about 85 million years ago. With broad jaws bearing as many as 1,400 teeth, hadrosaurids were previously thought to have chewing surfaces similar to other reptiles, which have teeth composed of just two tissues -- enamel, a hard hypermineralized material, and orthodentine, a soft bonelike tissue. But paleontologists who study the fossilized teeth of these animals in detail suspected that they were not that simple.

"We thought for a long time that there was more going on because you could just look at the surface of the tooth and see advanced topography, which suggests that there are many different tissues present," said Mark Norell, chair of the American Museum of Natural History's Division of Paleontology and an author on the paper.

To investigate the dinosaurs' dental structure and properties in depth, Norell worked with lead author Gregory Erickson, a biology professor at Florida State University, and a team of engineers on a series of novel experiments. Erickson sectioned the fossilized teeth and made microscope slides from them. These revealed that hadrosaurids actually had six different types of dental tissues -- four more than reptiles and two more than expert mammal grinders like horses, cows, and elephants. Using a technique called nanoindentation, in which a diamond-tipped probe is indented and/or drawn across the fossilized teeth to mimic the grinding of abrasive food, the researchers determined the differential hardness and wear rates of the dental tissues.

Erickson, who describes hadrosaurid dinosaurs as "walking pulp mills," said, "We were stunned to find that the mechanical properties of the teeth were preserved after 70 million years of fossilization." He went on to comment that "if you put these teeth back into a living dinosaur they would function perfectly."

In addition to the four dental tissues found in mammals -- enamel, orthodentine, secondary dentine that helps prevent cavities, and coronal cementum that supports the teeth's crests -- the hadrosaurid teeth include giant tubules and a thick mantle dentine. These extra tissues are thought to provide additional prevention against abscesses. Also unlike mammalian teeth, the dental tissue distribution in hadrosaurids greatly varied in each tooth.

Together, these characteristics suggest that hadrosaurids evolved the most advanced grinding capacity known in vertebrate animals, which might have led to their extensive diversification.

"Duck-bills' advanced tissue modification appears to have allowed them to radiate into specialized ecological niches where they ate extremely tough plants like fern, horsetail, and ground cover that were not as easy for dinosaurs with shearing teeth to eat," Norell said. "Their complex dentition could have played a major role in keeping them on the planet for nearly 35 million years."

In addition, the findings provide strong evidence that dental wear properties are preserved in fossil teeth -- an idea that was once questioned and overruled in this study with comparative tests on teeth from modern and fossilized horses and bison. This opens the door for studies on the dental biomechanics of fossils from wide-ranging groups of animals to better understand evolutionary modifications in diets.


Story Source:

The above story is based on materials provided by American Museum of Natural History. Note: Materials may be edited for content and length.


Journal Reference:

  1. G. M. Erickson, B. A. Krick, M. Hamilton, G. R. Bourne, M. A. Norell, E. Lilleodden, W. G. Sawyer. Complex Dental Structure and Wear Biomechanics in Hadrosaurid Dinosaurs. Science, 2012; 338 (6103): 98 DOI: 10.1126/science.1224495

Cite This Page:

American Museum of Natural History. "Duck-bill dinosaurs had plant-pulverizing teeth more advanced than horses." ScienceDaily. ScienceDaily, 4 October 2012. <www.sciencedaily.com/releases/2012/10/121004141753.htm>.
American Museum of Natural History. (2012, October 4). Duck-bill dinosaurs had plant-pulverizing teeth more advanced than horses. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2012/10/121004141753.htm
American Museum of Natural History. "Duck-bill dinosaurs had plant-pulverizing teeth more advanced than horses." ScienceDaily. www.sciencedaily.com/releases/2012/10/121004141753.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Fossils & Ruins News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Ruins Thought To Be Port Actually Buried Greek City

Ruins Thought To Be Port Actually Buried Greek City

Newsy (Nov. 24, 2014) Media is calling it an "underwater Pompeii." Researchers have found ruins off the coast of Delos. Video provided by Newsy
Powered by NewsLook.com
Amphipolis Tomb Architraves Reveal Faces

Amphipolis Tomb Architraves Reveal Faces

AFP (Nov. 22, 2014) Faces in an area of mosaics is the latest find by archaeologists at a recently discovered tomb dating back to fourth century BC and the time of Alexander the Great in Greece. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Uncovering Information About Hadrosaur Teeth

Oct. 11, 2012 An unusual collaboration between researchers in two disparate fields resulted in a new discovery about the teeth of 65-million-year-old ... read more

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins