New duck-billed dinosaur gives scientists clues to evolution of head ornamentation and provinciality

Jul 20, 2011

A new genus and species of hadrosaur (duck-billed) dinosaur – the oldest duck-billed dinosaur known from North America – has been named by scientists who expect the discovery to shed new light on dinosaur evolution.

The most striking feature of Acristavus gagslarsoni, the name given to the new dinosaur, is that its head lacked the distinctive ornamentation common to later duck-billed relatives. Acristavus means "non-crested grandfather." The genus name is symbolic of the animal's unadorned skull and the fact that it preceded later hadrosaurs.

All other hadrosaur fossils come with some kind of adornment on their skulls (with one exception from the end of the Cretaceous Period, the time just before the K-T extinction.) Ornamentation varied among hadrosaurs. Some adornments were hollow and part of the creatures' breathing apparatus, whereas others were solid. Scientists speculate the crests played a role in species recognition where one species could tell another apart by unique embellishments.

The new fossil hints that the two different styles of hadrosaur headgear evolved independently from an ancestor that did not possess ornamentation.

Especially exciting is that the two fossils of the 79.3 million-year-old dinosaurs were discovered in different locations, suggesting that earlier species of duck-billed roamed over a much larger region of North America than their successors four million years later.

"To find two specimens 650 miles apart that lived at virtually the same time, and were discovered within one year of one another is extremely rare in dinosaur paleontology," said Terry Gates, a research associate at Chicago's Field Museum, and a member of the team that documents the discovery in the July issue of the Journal of Vertebrate Paleontology.

The first fossil specimen was found in Montana in 1999 by the Old Trail Museum staff and volunteers, including a group of "junior paleontologists" from the University of Chicago and was excavated in 2001 and 2002 by study coauthor Rebecca Hanna for the Museum of the Rockies in Bozeman, Montana, where it now resides.

The Utah specimen was found in the year 2000 in Grand Staircase Escalante National Monument by study coauthor C. Riley Nelson, an entomologist from Brigham Young University, who reported his finding to a local paleontologist. The Utah Museum of Natural History in Salt Lake City excavated the specimen in 2003.

The researchers who described the new dinosaur are grateful to the family owning the Montana land where the first of the two fossils of Acristavus was found. "These private land owners are to be commended for their generosity because the dinosaur found on their property is an exceptionally important piece of the paleontological puzzle," says Hanna.

The Montana specimen was found on land originally owned by Cowboy Hall of Fame Member Russell Ellsworth "Gags" Larson (deceased) and his wife Nora Bush Larson of Choteau, Montana. It was donated to the Museum of the Rockies by their children. To honor the family patriarch, the scientists gave the species the scientific name gagslarsoni.

Explore further: Egypt archaeologists find ancient writer's tomb

Related Stories

New bony-skulled dinosaur species discovered in Texas

Apr 19, 2010

Paleontologists have discovered a new species of dinosaur with a softball-sized lump of solid bone on top of its skull, according to a paper published in the April issue of the journal Cretaceous Research.

Scientists announce new horned dinosaur

May 28, 2010

Michael J. Ryan, Ph.D., a scientist at The Cleveland Museum of Natural History, has announced the discovery of a new horned dinosaur, Medusaceratops lokii. Approximately 20 feet long and weighing more than 2 ...

80-million-year-old fossil found in Japan

Oct 15, 2007

The skull of a platypus-like dinosaur estimated to be more than 80 million years old has been discovered on a Japanese mountaintop near the town of Mifune.

Recommended for you

Egypt archaeologists find ancient writer's tomb

10 hours ago

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Crowd-sourcing Britain's Bronze Age

Apr 17, 2014

A new joint project by the British Museum and the UCL Institute of Archaeology is seeking online contributions from members of the public to enhance a major British Bronze Age archive and artefact collection.

Roman dig 'transforms understanding' of ancient port

Apr 17, 2014

(Phys.org) —Researchers from the universities of Cambridge and Southampton have discovered a new section of the boundary wall of the ancient Roman port of Ostia, proving the city was much larger than previously ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

FrankHerbert
0.9 / 5 (50) Jul 20, 2011
As "In before god did it," is considered spam (and evangelizing isn't), I will elaborate.

A duck billed dinosaur is an obvious evolutionary step between lizards and birds.

There's that fossil record you keep claiming doesn't exist.

More news stories

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.