When Pittsburgh paleontologist Matt Lamanna jokingly promised his fellow scientists that he would eat a duck foot if they unearthed a rare bird fossil, he never expected that they would discover a large group of them in northwest China. This discovery, the most significant in the past 25 years, was made in the Changma Basin, a desert located more than 1,000 miles away from the famed Liaoning fossil quarries.
"The dinosaur-bird transition is the hottest topic in dinosaur paleontology," says Lamanna.
Some evolutionary biologists think that birds and dinosaurs are too different to be directly related even though they shared a common ancestor. However, most paleontologists agree that birds descended directly from theropods --- meat-eating dinosaurs that include Tyrannosaurus rex, said Peter Dodson, an expert in dinosaur paleobiology at University of Pennsylvania, and Lamanna's doctoral advisor.
Most of the primitive birds from Liaoning belong to an unusual group of so-called "opposite birds" (the Enantiornithes), a group that vanished completely by the end of the "Age of Dinosaurs." However, the origins and early evolutionary history of the modern avian lineage (the Ornithuromorpha) remain poorly understood: no one knows how, when, or why this critical group rose to dominance.
Lamanna, now associate curator in vertebrate paleontology at the Carnegie Museum of Natural History, first became interested in avian evolution after fellow UPenn graduate, You Hailu of the Chinese Academy of Geological Sciences, showed him a picture of a bird fossil he discovered in the Changma Basin in northwest China.
"It was pretty exciting to see pictures of the stuff they found," Lamanna said. "I realized this was an incredible place, and knew we needed to try to get there."
Much of Lamanna's research focuses on Late Cretaceous dinosaurs and terrestrial vertebrates on continents that were once been part of a southern supercontinent known as Gondwana. This landmass included what is now Africa, India, Australia, Antarctica and South America.
You's bird fossil was only the second such find at Changma. The first, several bones comprising a fossilized lower left leg and foot, was discovered in 1981 by Chinese scientists, who realized it was a new species that they later named Gansus yumenensis [Historical Biology 17(1-4):7-14. doi: 10.1080/08912960500284851].
Lamanna is not new to fossil digs: he also pursues field work in the Bahariya Oasis in Egypt and in Patagonia, which is near the southern end of Argentina, South America. Some of his significant co-discoveries include the long-necked plant-eating dinosaur, Paralititan Stromeri, which is the second most massive dinosaur ever found, and Buitreraptor gonzalezorum, the oldest dromaeosaur ever found. Both fossils were found in South America.
To help Lamanna, You and paleontologist Jerry Harris get to China, Discovery and Science television channels agreed to co-sponsor expeditions in the summers of 2004 and 2005, and sent camera crews with them. Lamanna, who also is involved in public education and outreach for the museum, hosts the new television documentary, "Rise of the Feathered Dragon", that follows this fossil dig. This program debutes at tonight at 9pm on the Science Channel.
"I want to make a sound contribution to the study of dinosaurs. I'd like to be known as someone who can fill in our knowledge about dinosaurs from the Southern Hemisphere," Lamanna said.
Read more about it.
Note: A breaking story about Gansus was published in Science on 15 June 2006, and was written about here, The Rise of Feathered Dinosaurs, thanks to the authors, who sent me the manuscript and other background materials.
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I have been interested in the dinosaur-bird connection (as a non-scientist) ever since I first learned about it in grade school. I hope to see it sorted out one day.
It's neither here nor there, but Canada Geese always look very dinosaur-like to me when I see them foraging in large flocks. There is something about the way they walk with their heads bowed over and their necks stretched out. Other birds, not so much.
When I first heard about the dino-bird connection it made a lot of sense to me. Now that I have a parrot, there's something in how he looks at me that reminds me of the velociraptors in Jurassic Park. Thankfully he prefers fresh fruits and veggies to people!
How many times did dinosaurs develop flight? Put another way, do avians and pterodactyls descend from the same clade of dinosaurs, or are/were they both fliers due to convergent evolution?
Alon,
I remember some blogger (don't remember who) saying recently that wings had evolved 4 separate times--birds, insects, pterodactyls, and bats. This page illustrates it briefly, and this page goes into more depth.
Oops, don't think second link worked in previous post. Try here.
Alon,
The pterosaurs are a distinct lineage from the dinosaurs. The wing morphologies of pterosaurs and birds are also very different: in pterosaurs, the fourth finger is elongated to form the leading edge of the wing. There's a cladogram here.
the fun part is thinking of sparrows as dinosaurs! everytime i watch these crazy english sparrows hopping and fluttering and chirping around here, i think of em as tiny dinosaurs!
thanks for the links, everyone.
Barry; i also like thinking of my parrots as dinosaurs. it is easier to think of them this way on some days than others, especially after one of my feathery dinosaurs have bitten me.
Actually, _we_ didn't name the bird _Gansus yumenensis_ -- that name was given to the first specimen, consisting of just an isolated left foot, recovered in the early 1980's, by Hou Lian-hai and Liu Zhi-cheng in 1984. Our expedition only recovered many new, and much more complete (everything except the head and neck thus far!), specimens that provide a LOT more info on this bird. The specimen described in _Historical Biology_ isn't of _Gansus_; it's of an enantiornithean bird (one of the "opposite birds" that were the dominant terrestrial, perching birds of the Cretaceous); more specimens of those are also in press. Stay tuned to the literature for more news on these and _Gansus_...