8) Recent Dinosaur Discoveries In Utah And Wyoming
Geological Society of America
Imagine a one-ton Big Bird Ã la Sesame Street, but instead of friendly "hands",he has Freddie Claws. Thatâ€™s basically what the Therizinosaurid dinosaur looks like that geologist David Gillette's team from the Museum of Northern Arizona (MNA) found in Kane County, Utah.
"This is a one ton plant-eating carnivore with really bizarre claws",said Gillette. "It had slender arms and really long bones in the hand with bladed claws that look like sickles. With the sheath, the claws are about 15 inches long."
Gillette will present a preliminary report on their discovery May 7 at the Geological Society of America Rocky Mountain Section Meeting at the Southern Utah University campus.
He will also report on another uncommon findâ€”skin impressions of a duck-billed dinosaur known as a Hadrosaur. Gilletteâ€™s group found the impressions while excavating the dinosaurâ€™s tail in the new Grand Staircase-Escalante National Monument (GSENM) in Kane County.
"This is the second reported discovery of skin impressions in Utah",Gillette said. "On the global scale, however, this is a rare occurrence. This was a great discovery, especially in the context of the Hadrosaur with an articulated tail--that means the bones were still connected--that extended from the base of the tail (at the hips) to near the tip, about 13 feet long. In addition, the tendons that in life held the tail rigid were still preserved in life position."
The Grand Staircase-Escalante National Monument is about two million acres large and much of it is exposed and eroded rock, so fossils are usually only found in unrecognizable bits and pieces. But the MNA discovery was different.
"The rear half of the body was in beautiful state of preservation and in articulation. The discovery of the skin impressions came during the excavation, to our great delight and surprise,â€ Gillette said. â€œI would describe the skin as pebbled, with radiating grooves in each bump. The bumps were polygonal, nearly equilateral diamonds, pentagons, and hexagons. This texture surely added strength and toughness to the skin, which in turn would resist decay following death and burial. The carcass did not decay much prior to burial, but had to be desiccated to resist decomposition by bacteria--that is, the local environment must have been very dry."
Scott Sampson from the Utah Museum of Natural History will provide updates on his and his teamâ€™s discoveries from GSENM at the same May 7 session as Gilletteâ€”"Paleontological Research in Grand-Staircase Escalante National Monument and Surrounding Area."
Their findings include two previously unknown horned dinosaurs (ceratopsians), a partial skull of a dome-headed dinosaur (pachycephalosaur), a partial skeleton of a large-bodied tyrannosaur that is the first tyrannosaur from this time period in Utah, and the remains of two previously unknown giant crocodiles. Research for this project was funded by GSENM as part of a collaborative paleontological survey.
"Given how little is known of the dinosaurs from GSENM, chances are high that most of the dinosaur remains represent species new to science,â€ Sampson said. â€œNow the goal is to find enough of each of these ancient beasts to establish that they do represent new species. Our efforts and those of others over the past several years suggest that GSENM has perhaps greater potential to yield new and interesting kinds of dinosaurs than any other region in North America."
Based on different types of Late Cretaceous plants and animal discoveries in Montana and Alberta versus those found in New Mexico and Texas, Sampson and others speculate that Utah may be an important boundary area between two major "biozones".
"To really understand this paleoecological story, however, will require a good record from the Late Cretaceous of Utah,â€ Sampson said. â€œAnd GSENM will provide that record."
Brent H. Breithaupt, from the University of Wyomingâ€™s Geological Museum, will take a look at what he calls "Theropod family values" via a â€œlive-actionâ€ glimpse of their lives through intensive study of over 1,000 dinosaur tracks at the Red Gulch Dinosaur Tracksite in northern Wyoming. He will present his report May 8 at the Stratigraphy, Paleontology, Paleobotany, Archaeological Geology, and History of Geology session at the meeting.
"We have evidence of gregarious carnivorous dinosaurs. These are groups of animals moving together,â€ Breithaupt said. â€œTrace fossils such as tracks are unique in that they actually preserve the activities of ancient animals. In addition, as we have a very large and statistically valid database we can make some unique interpretations. This is important as evidence for gregarious carnivorous dinosaurs is relatively rare."
Using data from a variety of resources including aerial photography of the entire tracksite and close-range photogrammetric images of a single track, Breithaupt and his co-authors speculate there were family groups, ranging from yearlings to adults, interacting near their nesting area by a shore.
"The data also suggest a certain level of parental care and the level of dependence of the young dinosaurs, as we have juveniles traveling with adults" he said. "From what we know about dinosaur growth, it appears that they grew at the same rates as some modern ground birds such as ostriches and emus. If our dinosaurs represent animals of different ages of the same species then the smallest ones can't be very old--a year or perhaps less. Little animals of this sort probably aren't going to travel long distances during the first year. Thus, they were probably relatively near a large ground nesting area. If we accept the paradigm of theropod dinosaurs being similar to modern birds, then some of the behaviors and family structures may be similar as well."
The Dinosaur that Fooled the World
First shown: BBC Two 9.00pm Thursday 21 February 2002
In the mid 1800s, when Charles Darwin published his theory of evolution, one species of animal remained a mystery; where did birds fit on his evolutionary tree? Several years later his friend and colleague, Thomas Henry Huxley, came up with an answer. Huxley had recently examined a new fossil from southern Germany called Archaeopteryx which was causing considerable excitement in palaeontological circles. There were clear signs of feathers and it was obvious this was the earliest fossil evidence of a bird ever found. Huxley noticed something else as well. To him it looked as though the skeleton bore a striking similarity to that of a family of meat eating dinosaurs known as therapods.
In the 1860s, on the basis of this observation, he announced a new theory; birds must have evolved from dinosaurs. The theory ignited what was to become one of the biggest controversies in palaeontology. Could Huxley possibly be right; how could a large, land-bound creature like a dinosaur have ever evolved into something as light and sleek as a bird? Many questioned the accuracy of Huxley's observations and ever since there has been a search for further fossil evidence to confirm the theory; a transitional animal which would incontrovertibly show how, in one creature, birds had evolved from dinosaurs. It has become one of the big missing links in palaeontology.
In Spring 1999, at the Tucson Gem and Fossil Fair in Arizona, an American collector came across a new Chinese fossil which seemed to be just this transitional animal. It had the head and upper body of a bird but the tail of a dinosaur. It was called Archaeoraptor or 'ancient hunter'.
Throughout the 1990s a number of important fossils emerged from China showing an apparent relationship between dinosaurs and birds. Practically all come from a region in the north of the country called Liaoning, one of the richest fossil areas in the world. Here, 130 million years ago, volcanic eruptions buried a wetland once teeming in wildlife. Many of the fossils have been magnificently preserved in the fine silt; some even have the remains of soft tissue attached to them.
It was here, in 1996, that Chinese scientists found a creature they called Sinosauropteryx, an animal which bore many similarities to a dinosaur but appeared to have been covered in a feathery like coat. Two years later a joint Chinese/American team found an even more striking creature; a dinosaur like animal with very clear feathers which they called Caudipteryx. Other similar feathered dinosaurs followed, including in 1999, an important specimen called Sinornithosurus. Yet to those who questioned the relationship between dinosaurs and birds, these fabulous finds raised as many questions as they answered. Were the feather-like markings really signs of feathers, or were they something else? And were the skeletons really those of dinosaurs or were they, in fact, the skeletons of new, as yet unidentified, birds? What was still missing was the piece of evidence which would satisfy everybody.
The best of both worlds
The new Archaeoraptor fossil, also from the Liaoning region of China, seemed to be just that. Here, in one animal, was a unique range of dinosaur and bird features. It had the skull and upper body of a bird, but the teeth and hands of a dinosaur. It also had the legs of a bird but the tail of a dinosaur. It was the most complete set of transitional features ever found in one creature. In November 1999 National Geographic Magazine gave it a special mention in an article about the origins of birds, calling it, "a true missing link.". The debate, started by Thomas Huxley in the 1860s, seemed to have been resolved.
Yet within months, new finds in China showed Archaeoraptor to be an extremely clever fake. The head and upper body of a hitherto unidentified bird had been glued onto the tail of a previously unknown dinosaur. It was a journalistic disaster for National Geographic Magazine. The fossil, however, was anything but a disaster for palaeontology. By an extraordinary stroke of good luck, as scientists in China and America examined the head and tail separately, they found that both were, in their own right, unique and extremely valuable specimens. Both, in their different ways, contained powerful evidence that birds had evolved from dinosaurs