Featured Research

from universities, journals, and other organizations

Mini Dinosaurs Prowled North America

Date:
March 17, 2009
Source:
University of Calgary
Summary:
Massive predators like Albertosaurus and Tyrannosaurus Rex may have been at the top of the food chain, but they were not the only meat-eating dinosaurs to roam North America, according to Canadian researchers who have discovered the smallest dinosaur species on the continent to date. Their work is also helping re-draw the picture of North America's ecosystem at the height of the dinosaur age 75 million years ago.

This is an artists' illustration of Hesperonychus elizabethae by University of Calgary paleontologist Nick Longrich.
Credit: Nick Longrich

Massive predators like Albertosaurus and Tyrannosaurus rex may have been at the top of the food chain, but they were not the only meat-eating dinosaurs to roam North America, according to Canadian researchers who have discovered the smallest dinosaur species on the continent to date. Their work is also helping re-draw the picture of North America's ecosystem at the height of the dinosaur age 75 million years ago.

"Hesperonychus is currently the smallest dinosaur known from North America. But its discovery just emphasizes how little we actually know, and it raises the possibility that there are even smaller ones out there waiting to be found," said Nick Longrich, a paleontology research associate in the University of Calgary's Department of Biological Sciences. "Small carnivorous dinosaurs seemed to be completely absent from the environment, which seemed bizarre because today the small carnivores outnumber the big ones," he said. "It turns out that they were here and they played a more important role in the ecosystem than we realized. So for the past 100 years, we've completely overlooked a major part of North America's dinosaur community."

In a paper published March 16 in the scientific journal Proceedings of the National Academy of Sciences, Longrich and University of Alberta paleontologist Philip Currie describe a new genus of carnivorous dinosaur that was smaller than a modern housecat and likely hunted insects, small mammals and other prey through the swamps and forests of the late Cretaceous period in southeastern Alberta, Canada. Weighing approximately two kilograms and standing about 50 centimetres tall, Hesperonychus elizabethae resembled a miniature version of the famous bipedal predator Velociraptor, to which it was closely related. Hesperonychus ran about on two legs and had razor-like claws and an enlarged sickle-shaped claw on its second toe. It had a slender build and slender head with dagger-like teeth.

"It was half the size of a domestic cat and probably hunted and ate whatever it could for its size – insects, mammals, amphibians and maybe even baby dinosaurs," Longrich said. "It probably spent most of its time close to the ground searching through the marshes and forests that characterized the area at the end of the Cretaceous."

Fossilized remains of Hesperonychus, which means “western claw,” were collected in 1982 from several locations including Dinosaur Provincial Park. The most important specimen, a well-preserved pelvis, was recovered by legendary Alberta paleontologist Elizabeth (Betsy) Nicholls, after which the species is named. Nicholls was the curator of marine reptiles at the Royal Tyrrell Museum in Drumheller and earned her MSc and PhD degrees at U of C. She passed away in 2004. The fossils remained unstudied for 25 years until Longrich came across them in the University of Alberta’s collection in 2007. Longrich and Currie focused on fossilized claws and a well-preserved pelvis for their description.

"The claws were thought to come from juveniles- they were just so small. But when we studied the pelvis, we found the hip bones were fused, which would only have happened once the animal was fully grown", Longrich said. "Until now, the smallest carnivorous dinosaurs we have seen in North America have been about the size of a wolf. Judging by the amount of material that was collected, we believe animals the size of Hesperonychus must have been quite common on the landscape."

Currie and Longrich last year described the previous record-setting small North American dinosaur, a chicken-sized insectivore named Albertonykus borealis.

The discovery of Hesperonychus is the first sign of small carnivorous dinosaurs in North America and also extends the timeframe of small, birdlike dromaeosaurs known as the Microraptorinae in the fossil record by approximately 45 million years. Specimens from China have been found dating to 120 million years ago, while Hesperonychus appeared to have thrived until the end of dinosaur age in the late Cretaceous.


Story Source:

The above story is based on materials provided by University of Calgary. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nicholas R. Longrich and Philip J. Currie. A microraptorine (Dinosauria-Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0811664106

Cite This Page:

University of Calgary. "Mini Dinosaurs Prowled North America." ScienceDaily. ScienceDaily, 17 March 2009. <www.sciencedaily.com/releases/2009/03/090316173218.htm>.
University of Calgary. (2009, March 17). Mini Dinosaurs Prowled North America. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2009/03/090316173218.htm
University of Calgary. "Mini Dinosaurs Prowled North America." ScienceDaily. www.sciencedaily.com/releases/2009/03/090316173218.htm (accessed September 23, 2014).

Share This



More Fossils & Ruins News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Ice Age Wooly Mammoth Remains for Sale

Raw: Ice Age Wooly Mammoth Remains for Sale

AP (Sep. 23, 2014) A rare, well-preserved skeleton of a woolly mammoth is going on sale at Summers Place Auctions hope the 11.5-foot tall, almost intact specimen will fetch between $245,000 to $409,000. (Sept. 23) Video provided by AP
Powered by NewsLook.com
Dinosaur With Mysteriously Large Nose Discovered In Utah

Dinosaur With Mysteriously Large Nose Discovered In Utah

Newsy (Sep. 23, 2014) Rhinorex condrupus had a nose so big it was dubbed "King Nose," but scientists aren't sure what purpose it served. Video provided by Newsy
Powered by NewsLook.com
Iconic 'Easy Rider' Chopper Bike to Go on Auction Block

Iconic 'Easy Rider' Chopper Bike to Go on Auction Block

AFP (Sep. 19, 2014) The iconic Harley-Davidson motorbike ridden by Peter Fonda in the 1969 classic "Easy Rider" is to go under the hammer in California, and auctioneers predict it will make at least $1 million. Duration: 01:09 Video provided by AFP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 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:

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