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New dinosaur discoveries from Utah and Wyoming

From: Ben Creisler bh480@scn.org

Mention of some new dinosaur discoveries from Utah and 
Wyoming in a 5-7-02 press release from the Geological 
Society of America:

Imagine a one-ton Big Bird à la Sesame Street, but instead 
of friendly ?hands,? he has Freddie Claws. That?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.? 
In 2001, Gillette?s crew found an almost complete 
skeleton, which is a rare find. Some Therizinosaurid 
remains found in China caused quite a stir because they 
were found with feather-like structures on them. The idea 
that these creatures were among the ancestors of birds has 
been gaining increased acceptance. 
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 
He will also report on another uncommon find?skin 
impressions of a duck-billed dinosaur known as a 
Hadrosaur. Gillette?s group found the impressions while 
excavating the dinosaur?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 
?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,? Gillette said. ?I 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 team?s discoveries from 
GSENM at the same May 7 session as Gillette?
?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 
?Given how little is known of the dinosaurs from GSENM, 
chances are high that most of the dinosaur remains 
represent species new to science,? Sampson said. ?Now 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,? Sampson said. ?And GSENM will provide that record.? 
Brent H. Breithaupt, from the University of Wyoming?s 
Geological Museum, will take a look at what he 
calls ?Theropod family values? via a ?live-action? 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,? Breithaupt 
said. ?Trace 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.?