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2009-05-10 – Utah, USA: ritrovata una tartaruga fossile incinta (fossil pregnant turtle)

Rare prehistoric pregnant turtle found in Utah

At least three eggs are visible from the outside of the fossil, and Montana State University researchers this week have been studying images taken from a CT scan in search of others inside.

Montana State graduate student Michael Knell says the turtle was probably about a week from laying her eggs when she died and became entombed for millions of years in sandstone.

The fossil was found in 2006 in a remote part of Grand Staircase-Escalante National Monument. The eggs weren’t discovered until after it sat in storage for two years and was being re-examined by a volunteer.

This image provided Montana State University shows CT technician, Tanya Spence preparing to run a 75 million-year-old turtle fossil through a CT scanner at Deaconess Hospital in Bozeman, Mont. (AP Photo/Montana State University, Kelly Gorham)

This image provided Montana State University shows CT technician, Tanya Spence preparing to run a 75 million-year-old turtle fossil through a CT scanner at Deaconess Hospital in Bozeman, Mont. (AP Photo/Montana State University, Kelly Gorham)


maggio 10, 2009 Posted by | - Rettili, 1 Cretaceo, America Northern, An. Vertebrates, Articolo sc. di riferimento, Mesozoic, P - Preservazione eccezionale, P - Ritrovamenti fossili, Paleontology / Paleontologia, X - Nature | , , , , , , , , , | Lascia un commento

2008-11-09 – Utah, USA: Nessuna “pista da ballo” per i dinosauri (no “dinosaur dance floor”)

Un sopralluogo di altri ricercatori (i paleontologi Brent Breithaupt, Alan Titus e Andrew Milner, e il geologo Rody Cox) afferma che le persunte impronte di dinosauri recentemente descritte (in Vermilion Cliffs National Monumen) non sono altro che forme di erosione. Intanto gli autori dello studio Marjorie Chan and Winston Seiler, sembrano convincersi delle critiche; e in particolare Marjorie Chan si difende affermando che se le tracce sono effettivamente forme di erosione sono diverse da quelle che si ritrovano all’interno della stessa formzione rocciosa.

precedente post: 2008-10-20 – USA: nuovo ritrovamento di impronte di dinosauri, la “sala da ballo”! (dinosaur tracks,”dinosaur dance floor”)


Paleontologists Doubt ‘Dinosaur Dance Floor’

Potholes or Tracks? Both Sides Team for Follow-up Study

Media Contacts

Nov. 7, 2008 – A group of paleontologists visited the northern Arizona wilderness site nicknamed a “dinosaur dance floor” and concluded there were no dinosaur tracks there, only a dense collection of unusual potholes eroded in the sandstone.

So the scientist who leads the University of Utah’s geology department says she will team up with the skeptics for a follow-up study.

“Science is an evolving process where we seek the truth,” says Marjorie Chan, professor and chair of geology and geophysics, and co-author of a recent study that concluded the pockmarked, three-quarter-acre site in Vermilion Cliffs National Monument was a 190-million-year-old dinosaur “trample surface”.

“We went through the proper scientific process of careful study, comparisons with other published works and peer review” of the study by independent scientists, Chan adds. “We gave the project considerable critical thought and came up with a different interpretation than the paleontologists, but we are open to dialogue and look forward to collaborating to resolve the controversy.”

On Oct. 30 – more than a week after the Utah study was publicized worldwide – four scientists hiked to the remote wilderness-area site: paleontologist Brent Breithaupt, director and curator of the University of Wyoming’s Geological Museum; U.S. Bureau of Land Management paleontologist Alan Titus and geologist Rody Cox; and paleontologist Andrew Milner of the St. George (Utah) Dinosaur Discovery Site at Johnson Farm.

They saw dinosaur tracks en route, but none in the pockmarked “dance floor.”

“There simply are no tracks or real track-like features at this site,” Breithaupt says. “We will be investigating the formation of these features in the upcoming study. Science works best when scientists work together.”

Chan and Winston Seiler, who conducted the research as part of his master’s thesis, say they are not retracting their study, which was published in the October issue of Palaios, an international paleontology journal. But they acknowledge there are strong arguments for the features being potholes rather than dinosaur tracks. The original study cited the possibility that the features were potholes and outlined arguments against it.

Chan says if the features are potholes, they are extremely unusual compared with typical potholes on the Colorado Plateau – and their formation still needs to be explained fully. She will work with Breithaupt and the others to examine the site in greater detail.

“A reinterpretation could emerge, but those conclusions have not yet been written as a scientific paper and need to be submitted to a journal for publication after peer review by other scientists,” she says.

Nevertheless, the University of Utah geologists feel obligated to inform the public of the difference of opinion because of wide publicity about the “dinosaur dance floor.”

“The public interest has been tremendous, and fortunately there are many other fantastic, accessible, documented dinosaur track sites than can be visited in the area,” Breithaput says.

Seiler spent considerable time at the unusual site. He acknowledges that the dinosaur track interpretation is controversial, further study is warranted, and if the paleontologists turn out to be correct, “that’s part of science.”

Chan adds: “This is how science works, and we’ll have to see how it shakes out in the end.”

The original Oct. 20 “dinosaur dance floor” news release and high-resolution photos are at:



previous post: 2008-10-20 – USA: nuovo ritrovamento di impronte di dinosauri, la “sala da ballo”! (dinosaur tracks,”dinosaur dance floor”)


Other links:

Paleontologists Doubt ‘Dinosaur Dance Floor’
Science Daily (press release) – 7 nov 2008
7, 2008) – A group of paleontologists visited the northern Arizona wilderness site nicknamed a “dinosaur dance floor” and concluded there were no dinosaur tracks there, only a dense collection of unusual potholes eroded in the sandstone.
Dinosaur experts bust up prehistoric party theory The Associated Press
Dancing with the dino stars: Dispute boils Salt Lake Tribune
Newspost Online – United Press International – – Salt Lake Tribune
e altri 110 articoli simili »

novembre 9, 2008 Posted by | - R. Dinosauri, 2 Jurassic / Giurassico, America Northern, Italiano (riassunto), P - Impronte, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | Lascia un commento

2008-10-29 – Utah, USA: Ritrovati resti di piante fossili durante scavi (Plant fossils)

 Durante la costruzione di un parco industriale è stato trovato un sito con resti di Conifere risalente a 198 milioni di anni fa. L’area è tra l’altro vicina al Dinosaur Discovery Site dove otto anni fa sono stati scoperte migliaia di impronte di dinosauri. I riceracatori si stanno preparando a raccogliere i reperti che saranno donati a vari musei statali.

vedi pure: 2008-10-26 – Utah, USA: uno dei posti migliori per i dinosauri (world’s best spots for dinosaurs)


Plant fossils found near construction site in S. Utah

They are the only flora fossils ever found from the early Jurassic Period in the Western U.S.

ST. GEORGE – Stone fossils of plants that once fueled dinosaurs as they roamed around southern Utah some 198 million years ago were unveiled Tuesday at a ceremony.
    They were discovered Friday during construction work on a new industrial park.
    The fossils of the prehistoric flora, mainly conifers, are the only ones ever found from the early Jurassic Period in the Western United States.
    The site sits next to the Dinosaur Discovery Site at Johnson Farm, where eight years ago thousands of dinosaur tracks were discovered; they are now protected as a city-owned museum.
    Now developers will work with scientists to preserve the site.
    “This plant site is extremely important to help us examine further the vegetation recovery of plant life during the mass extinction at the end of the Triassic Period,” said Utah State Paleontologist Jim Kirkland.
    Kirkland said the area where the plant fossils and tracks are found was once on a vast lake’s northern shore that attracted dinosaurs.
    Andrew Milner, paleontologist for St. George, said one of the plant species, Saintgeorgeia jensenii is named after the city and another has been named after him, Milnerites planus.
    Trapped in the sedimentary stone, brown juniperlike leaves can be recognized sprouting from stems. Fossilized pine cones also were found.
“They [developers] have been very cooperative,” Kirkland said. “Because it is on private property, they could have told us to get lost and sold everything on eBay.”
    Don DeBlieux, a paleontologist with Utah Geological Survey, said several scientists descended on the site Sunday and have been splitting open stones since.
    “It’s neat,” DeBlieux said. “We’re finding a lot of things we haven’t seen before.
    Scientific museums around the country are interested in the find and have requested some of the fossils.
    Kirkland said samples will be shipped to the Smithsonian Institution, the Museum of Natural History in New York City, the University of California Berkeley, the University of Utah and Brigham Young University, among others.


see also: 2008-10-26 – Utah, USA: uno dei posti migliori per i dinosauri (world’s best spots for dinosaurs)


Other links:

Washington Post

Paleontologists sift Utah soil for plant fossils
The Associated Press – 1 ora fa
The spot is in a bare lot near the Virgin River, not far from the city’s Dinosaur Discovery Site at Johnson Farm, where dinosaur tracks were found eight years ago. Andrew Milner, the city’s paleontologist, said the property’s developers have agreed to
Plant fossils found near construction site in S. Utah Salt Lake Tribune
Crews sift St. George soil for plant fossils
e altri 52 articoli simili »

ottobre 29, 2008 Posted by | 2 Jurassic / Giurassico, America Northern, Curiosità, Italiano (riassunto), P - Paleobotanica, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , | Lascia un commento

2008-10-26 – Utah, USA: uno dei posti migliori per i dinosauri (world’s best spots for dinosaurs)

Nello Utah vi sono numerosi siti e musei che ospitano resti di dinosauri, vedi il seguente articolo:

Utah one of world’s best spots for dinosaurs

Sunday, October 26, 2008

(10-26) 04:00 PDT Moab, Utah — The bluffs and hills of this mountain biking hub were as red as a sunburn and barren, save for a few juniper trees and clumps of rabbit brush.

As I hiked to a flat stretch of sandstone, I saw them – bigger and more clearly defined than I had expected: Dinosaur tracks.

I ran my fingers along the curve of the claw and pressed my palm inside the hubcap-size impression. It was a creepy feeling occupying the same spot as an SUV-sized lizard.

When the giant meat-eater, probably an allosaurus, walked across this spot about 150 million years ago, the landscape was a tropical environment on the shores of an inland sea, lush with ferns, cycads, conifers and ginkgo trees.

Here, the beast’s feet sank into a sandbar. Over time, seismic forces buried, solidified and then pushed that sandbar to the surface, retaining in astonishing detail the prints of that long-extinct monster.

A happy geological fluke has made Utah one of the world’s best spots to hunt for dinosaurs. Throughout the rest of the United States, this fossil-rich layer of sedimentary rock is buried under prairies and forests. But in the badlands of Utah, the stratum rests near the surface, even along hiking trails like this one.

I consulted Utah’s top paleontologists on the best way to make a four-day road trip to see the state’s dinosaur exhibits. They told me the best time to visit is now, during an era of astounding discoveries. Thanks to improved technology and exploding interest in the field, paleontologists are digging up new dinosaur species around the world at a rate of 10 to 20 each year.

Utah’s quarries have been at the forefront, producing such discoveries as a strange duck-billed herbivore, a new horned quadruped, plus evidence that some dinosaurs fished.

In September, I drove the length and breadth of Utah – 978 miles. Here are my favorite stops.


St. George

St. George Dinosaur Discovery Center, Johnson Farm: Eight years ago, Sheldon Johnson, a retired optometrist, was prepping land for resale when he spotted something in the soil. He uncovered thick mudstone slabs imprinted with thousands of dinosaur prints, including skin impressions and tracks from what paleontologists believe was the lanky, fast-moving coelophysis of the early Jurassic period.

Johnson notified paleontologists and city officials, who later built a museum around the 200-million-year-old impressions. Among the exhibits is the world’s largest slab of stone containing dinosaur prints, weighing more than 26 tons.

From bones, paleontologists learn about the size, anatomy and diet of dinosaurs. From track prints, experts get clues on how they sat, ran, turned and hunted. Andrew C. Milner, the city’s paleontologist, believes scratch marks on several slabs suggest some dinosaurs swam in the shallows pursuing fish.

The drive: From Las Vegas, drive two hours along Interstate 15 to St. George in the southwest corner of Utah.

The vitals: Open 10 a.m. to 6 p.m. Monday through Saturday. Admission: $5 for adults, $2 for children. 2180 E. Riverside Drive, St. George; (435) 574-3466 or


Mill Canyon Dinosaur Trail and Copper Ridge Dinosaur Trackway: I drove 13 miles north of Moab to a hiking trail on U.S. Bureau of Land Management territory in Mill Canyon.

There, exposed to the elements were dozens of dinosaur bones, black, gray and grainy, like wood. The disjointed bones jutting out of a sandstone shelf were the vertebrae of a 20-ton camasaurus. A diamond-shape bone embedded in rock was the femur of an allosaurus, a smaller cousin of Tyrannosaurus rex.

The BLM installs interpretive markers on sites but doesn’t post road signs for fear that too many visitors will “love the fossils to death,” according to BLM officials. Damaging or removing a dinosaur or other vertebrate fossil from state or federal land without a permit is illegal.

The nearby Copper Ridge Dinosaur Trackway was slightly easier to find. After hiking from a parking lot, I came to several 150-million-year-old prints on a flat rock path, as clear as if they had been made that week. The three-toed allosaurus prints cross the path diagonally, but the bigger prints, probably made by a apatosaurus, seem to make a sharp right turn, a move that paleontologists say is unusual.

The drive: Drive Interstate 70 across Utah from St. George to Moab. Don’t rush past chocolate hoodoos, sherbet-colored mesas and the spectacular vista of Castle Valley at a rest area near mile marker 104.

The vitals: Both track sites are open year-round. For Mill Canyon, take U.S. Highway 191 north from Moab for 13 miles, turn left on Mill Canyon Road after mile marker 141. After reaching a “T” in the dirt road, turn left and look for a gravel parking lot and interpretive sign. For Copper Ridge, drive past mile marker 148, along U.S. 191, about 23 miles north of Moab, turn right on the next dirt road and follow the signs for 2 miles to a gravel parking lot. For information, contact the BLM’s Moab Field Office, 82 E. Dogwood, Moab; (435) 259-2100.


Cleveland-Lloyd Dinosaur Quarry: In the 1930s, near Cleveland, about 30 miles south of Price, paleontologists uncovered the densest collection of fossils in the world – more than 12,000 bones in one-quarter of an acre.

More surprising was the mystery of why there were so many bones in one spot, most from juvenile and adolescent carnivores such as the allosaurus. Fewer than 30 percent were herbivores, and paleontologists have been unable to find an intact skull.

Some suggest the land was a bog that trapped herbivores and attracted predators. But that doesn’t explain a preponderance of predator bones.

It looked like a mass grave, except for the fossilized dinosaur egg found in 1987.

The drive: To reach the quarry from Cleveland, drive 12 miles along unpaved roads. A four-wheel drive vehicle is recommended.

The vitals: Open 10 a.m. to 5 p.m. Monday through Saturday and noon to 5 p.m. Sunday from Memorial Day to Labor Day. Open Friday through Sunday in fall and spring. From November to mid-March, the quarry is closed. Admission: $5 for adults. Children under 16 are free. Take Utah Highway 10 south to the Cleveland/Elmo turnoff and follow the signs. For information, call the BLM office at Price, (435) 636-3600 or


Utah Field House of Natural History: In northeastern Utah, the visitors’ center at Dinosaur National Monument in Jensen is one of the state’s premier fossil viewing sites. Unfortunately, the center was closed indefinitely in 2006. I headed instead to nearby Vernal to see the Utah Field House of Natural History.

The star of the museum is a 90-foot-long diplodocus skeleton. The field house was designed as an educational center, with hands-on exhibits for kids. A 15-minute movie explained the Morrison Formation – the fossil-rich sedimentary layer that stretches 600,000 square miles from Canada to the American West.

The drive: Drive about seven miles outside Vernal along U.S. 191 to Red Fleet State Park and dinosaur tracks on the northern shore of the lake. These prints, at the end of a 1.5-mile hike, are not as distinct as the impressions on Copper Ridge but are impressive.

The vitals: Open 9 a.m. to 5 p.m. daily, except holidays. Admission: $6 for adults, $3 for seniors and children. 496 E. Main St., Vernal; (435) 789-3799 or


BYU Earth Science Museum: Brigham Young University Earth Science Museum is a research center – students behind a glass partition clean bones, and the dinosaur displays are magnificent.

Highlights include the skeleton of a torvosaurus, a predator with teeth that hang like stalactites. Bones of museum skeletons are reproductions because fossils are too fragile to mount. One fossil under glass is the 4-foot-tall leg bone of a Utahraptor, the nasty larger cousin of the turkey-sized velociraptor.

The drive: Through Manti-La Sal National Forest along U.S. Highway 6.

The vitals: Open 9 a.m. to 5 p.m. Monday through Friday. Admission is free, but donations are accepted. 1683 N. Canyon Road, Provo; (801) 422-3680 or go to



North American Museum of Ancient Life, Thanksgiving Point: This place brings the dinosaur era to life, complete with spooky lighting and eerie sound effects. The 86,000-square-foot museum – the world’s largest collection of life-size dinosaur skeleton casts – is part of a 700-acre commercial development that includes gardens, golf greens, shops, animal park, farmers market and more.

Thanksgiving Point museum has benefited from the backing of Alan Ashton, co-founder of WordPerfect, one of Forbes magazine’s 400 wealthiest Americans in 1995. The $20-million museum was built in 2000. A two-story-tall torvosaurus is the museum’s doorman. It’s just the opening act.

Home to more than 60 complete dinosaur skeletons, the museum is divided into four sections, each representing a period of Earth’s history: the Precambrian age, when Earth was a bubbling caldron of single-cell critters, and the Triassic, Jurassic and Cretaceous periods. The sounds of prehistoric birds echo from hidden speakers.

The supersaurus, one of the world’s largest dinosaurs, stretches 110 feet from head to tail. The neck of the supersaurus is so long it extends into the next exhibit hall.

The drive: From Provo to Lehi, follow Interstate 15 past industrial warehouses and strip malls.

The vitals: Open 10 a.m. to 8 p.m. Monday through Saturday, except Thanksgiving and Christmas. Admission: $10 for adults; $8 for children. Admission plus a 3-D dinosaur battle movie: $15 for adults; $12 for children. 3003 N. Thanksgiving Way, Lehi. (888) 672-6040 or go to

To comment, visit and follow the links.

This article appeared on page E – 6 of the San Francisco Chronicle



ottobre 28, 2008 Posted by | - R. Dinosauri, America Northern, Italiano (riassunto), Musei, Paleontology / Paleontologia | , , , , | 2 commenti

2008-10-20 – USA: nuovo ritrovamento di impronte di dinosauri, la “sala da ballo”! (dinosaur tracks,”dinosaur dance floor”)

Pubblicato sul numeo di Ottobre della rivista Palaios, dai ricercatori dell’università dello Utah Winston M. Seiler e Marjorie A. Chan, uno studio preliminare su un nuovo sito contenente tracce di dinosauri.

L’area è situata al confine tra Arizona e Utah e gli strati contenenti le tracce appartengono alla Navajo Sandstone Formation e risalgono a 190 milioni di anni fa (Giurassico inferiore).

Le tracce sia di piedi che di code presentano un’elevata densità di frequenza, sono state attribuite ad almeno tre ichnogeneri cf. Eubrontes, cf. Anchisauripus, cf. Grallator, e curiosamente fino ad ora erano state ritenute forme di erosione superficiale.

Il rinvenimento di tali impronte è significativo anche perche le aree della Navajo Sandstone Formation erano ritenute un unico immenso deserto, ma il fatto che vi fossero animali con elevate necessità fa ritenere invece dovevano essere presenti anche aree on risorse sufficienti al loro fabbisogno.


Public release date: 20-Oct-2008
Contact: Lee Siegel
University of Utah

‘A dinosaur dance floor’

Numerous tracks at Jurassic oasis on Arizona-Utah border

Geologist Winston Seiler with some of the dinosaur tracks he identified for his thesis as a University of Utah master’s degree student. The impressions once were thought to be potholes…
Click here for more information.

SALT LAKE CITY – University of Utah geologists identified an amazing concentration of dinosaur footprints that they call “a dinosaur dance floor,” located in a wilderness on the Arizona-Utah border where there was a sandy desert oasis 190 million years ago.

The three-quarter-acre site – which includes rare dinosaur tail-drag marks – provides more evidence there were wet intervals during the Early Jurassic Period, when the U.S. Southwest was covered with a field of sand dunes larger than the Sahara Desert.

Located within the Vermilion Cliffs National Monument, the “trample surface” (or “trampled surface”) has more than 1,000 and perhaps thousands of dinosaur tracks, averaging a dozen per square yard in places. The tracks once were thought to be potholes formed by erosion. The site is so dense with dinosaur tracks that it reminds geologists of a popular arcade game in which participants dance on illuminated, moving footprints.

“Get out there and try stepping in their footsteps, and you feel like you are playing the game ‘Dance Dance Revolution’ that teenagers dance on,” says Marjorie Chan, professor and chair of geology and geophysics at the University of Utah. “This kind of reminded me of that – a dinosaur dance floor – because there are so many tracks and a variety of different tracks.”

“There must have been more than one kind of dinosaur there,” she adds. “It was a place that attracted a crowd, kind of like a dance floor.”

A study identifying the dinosaur track site was published in the October issue of the international paleontology journal Palaios. Chan is senior author of the study, which was conducted for a master’s degree thesis by former graduate student Winston Seiler, who now works at Chevron Inc., in Bakersfield, Calif.

University of Utah geologist Winston Seiler walks among hundreds of dinosaur footprints in a “trample surface ” that likely was a watering hole amid desert sand dunes during the Jurassic Period…
Click here for more information.

Seiler says the range of track shapes and sizes reveals at least four dinosaur species gathered at the watering hole, with the animals ranging from adults to youngsters.

“The different size tracks [1 inch to 20 inches long] may tell us that we are seeing mothers walking around with babies,” he says.

The site – a 6-mile roundtrip hike from the nearest road – is in Arizona in the Coyote Buttes North area of the Paria Canyon-Vermilion Cliffs Wilderness, which is part of the U.S. Bureau of Land Management’s (BLM) Vermilion Cliffs National Monument. The track site – about halfway between Kanab, Utah, and Page, Ariz. – is near a popular wind-sculpted sandstone attraction known as the Wave.

A Dense Collection of Dinosaur Footprints – and a Few Tail Drags
 Chan says the new study is the first scientific publication to identify the impressions as dinosaur footprints on a trample surface.

As part of the study, Seiler marked off 10 random plots, each of 4 square meters, or roughly 2 yards by 2 yards. He counted 473 tracks within those plots – an average of 12 per square meter. He conservatively estimates the 3,000-square-meter site (about 0.75 acres) has more than 1,000 tracks, but he and Chan believe there perhaps are thousands.

Numerous dinosaur track sites have been found in the western United States, including more than 60 in Navajo Sandstone, where actual dinosaur bones are rare.

“Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000,” Seiler and Chan wrote. And they say the density of tracks is much greater than it is at even larger track sites, such as the one at Coral Pink Sand Dunes State Park in Utah.

The dinosaur tracks and tail marks near the Wave were preserved in the vast Navajo Sandstone Formation. But unlike the dunes that make up much of the Navajo Sandstone, the tracks are within what was a wet, low watering hole between the dunes.

“We’re looking at an area much like the Sahara Desert with blowing sand dunes,” Seiler says. “Areas between these sand dunes could have had ponds – oases.”

The 2.4-inch-wide tail-drag marks – which are up to 24 feet long – are a special discovery because there are fewer than a dozen dinosaur tail-drag sites worldwide, Seiler says. Four tail drags were within the 10 plots he surveyed, and there are others nearby.

“Dinosaurs usually weren’t walking around with their tails dragging,” he says.

This Eubrontes dinosaur footprint — including three toes and a heel — measures roughly 16 inches long. Dinosaur footprints are named by their shape because the species and genus of…
Click here for more information.

Potholes – or Prints from Four Kinds of Dinosaurs?
 Chan first visited the site of the dinosaur tracks in 2005 with a BLM ranger who was puzzled by them. Chan initially called them potholes, which are erosion features common in desert sandstone, “but I knew that wasn’t the whole story because of the high concentration and because they weren’t anywhere else nearby but along that one surface.”

Seiler first saw the site in 2006. “At first glance, they look like weathering pits – a field of odd potholes,” he says. “But within about five minutes of wandering around, I realized these were dinosaur footprints.”

One anonymous reviewer of the Palaios study still believes the holes are erosion features. The study argues the impressions are from dinosaurs because:


  • They are the correct size for tracks made by big animals, and are limited to a single rock bed.  
  • Four different kinds of footprint shapes are seen repeatedly in 14 percent of the impressions, and they include obvious claw, toe and heel marks. The other impressions “are clearly similar.”  
  • One-third of the prints are surrounded by small ridges or mounds. Such features would be expected when animals stepped in wet sand.  
  • The tracks “are rarely flat and are typically oriented at an angle into the sediment … and indicate a clear direction of travel” to the west-southwest. Seiler says the direction the dinosaurs walked “either was dictated by the large dunes that bounded this wet area, or it could be communal behavior, like walking together as a pack.”  
  • About one-eighth of the tracks show “overprinting,” in which a dinosaur stepped in the footprint of another or even in its own prints. 

“While these impressions may be mistaken for potholes caused by weathering, close examination reveals many footprint features,” Seiler says.

Dinosaur footprints are named by their shape because the animals that made them haven’t been identified. Four kinds of footprints were found on the trample surface:


  • Eubrontes footprints measure 10 inches to 16 inches long and have three toes and a heel. Eubrontes tracks are believed to have been made by upright-walking dinosaurs 16 to 20 feet long, or smaller than Tyrannosaurus rex.  
  • Grallator tracks are about 4 inches to 7 inches long, are three-toed and were left by small dinosaurs only a few feet tall.  
  • Sauropodomorph dinosaur tracks, which are more circular than the other types, were left by creatures that walked on four legs and were the largest dinosaurs at the site. Their tracks range from 6 inches to 11 inches long. Seiler says the tail-drag marks are associated with these circular footprints, so they likely were made by sauropods.  
  • Anchisauripus tracks measure 7 inches to 10 inches long and were made by dinosaurs that ranged from 6 feet to 13 feet in length. 
An Oasis for Dinosaurs in a Vast Desert of Dunes
 When the footprints were made 190 million years ago, “the continents were arranged so this area was in the tropics” and was part of the supercontinent named Pangaea, says Seiler. “It was a desert, like the Sahara but much larger than the Sahara is today,” covering much of Utah, Wyoming, Colorado, New Mexico, Arizona and Nevada.

“Some studies indicate winds probably were much stronger than normal because all the continents were together,” says Chan. “That’s why you had monster dunes.”

“To support large dinosaurs, there probably wasn’t just one watering hole for them to go to, but many,” Seiler says. “They wandered between a network of watering holes for food and water.”

In that sense, the trample surface is not “just a wet pond,” but “it’s possibly a record of global climate change” – a shift from drier to wetter conditions, Chan says.

She says the traditional view is that the Navajo Sandstone represents “a vast, dry uninhabitable desert. But now we are seeing there are a lot of variations, and there were periods when dinosaurs were living there.”

Seiler envisions the dinosaurs were “happy to be at this place, having wandered up and down many a sand dune, exhausted from the heat and the blowing sand, relieved and happy to come to a place where there was water.”

The trample surface “helps paint a picture of what it was like to live back then,” he says. “Tracks tell us what the dinosaurs were doing, what their behavior was, what life was like for them, what they did on a day-to-day basis.”

After the dinosaurs left their prints, the trample surface was covered by shifting dunes, which eventually became Navajo Sandstone. Then, the rock slowly eroded away, exposing the tracks. The tracks eventually will erode too, Seiler says.


 Seven additional images relevant to this press release are available:

Dinosaur Footprints and Tail-drag Marks
Grallator Dinosaur Track
Sauropodomorph Dinosaur Track
Dinosaur Trackway
Extent of the ‘Dinosaur Dance Floor’
Dinosaur Dance Floor Locator Map
Geologist Winston Seiler

Note: Access to Area is Limited, Permits Required

The dinosaur trample surface and a nearby feature known as the Wave are in the Coyote Buttes North Special Permit Area of the Paria Canyon-Vermilion Cliffs Wilderness Area. A permit and $7 per person fee are required to enter the area.

There is now a four-month wait for the 10 permits issued daily by phone or online. For permits by phone, call the U.S. Bureau of Land Management in St. George, Utah, at (435) 688-3246. For information and permits online, go to , and then click on “Coyote Buttes.” (If Coyote Buttes page doesn’t open, follow instructions to enable TLS security.)

An additional 10 permits are issued daily – one day in advance of the hike – during a 9 a.m. walk-in lottery March 15-Nov. 14 at the Paria Contact Station, and Nov. 15-March 14 at the BLM’s Kanab (Utah) Field Office.

News media interested in accessing the area should contact Linda Price, Vermilion Cliffs National Monument manager, at (435) 688-3241.

University of Utah Public Relations
201 Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: (801) 585-3350



In German:

Dancefloor für Dinos
Spiegel Online – 1 ora fa
Hunderte Fußabdrücke von Sauriern glauben Paläontologen im Westen der USA gefunden zu haben. Die Spuren liegen so dicht beieinander, dass die Forscher den
190 Millionen Jahre alt: Forscher entdecken Dinosaurier-Treffpunkt
Hannoversche Allgemeine (Abonnement) – 1 ora fa
Auf einen 190 Millionen Jahre alten Versammlungsplatz von Dinosauriern sind US-Forscher gestoßen. Bisher haben die Wissenschaftler mehr als 1000 Spuren
Dinosaurier-“Tanzboden” entdeckt
scinexx | Das Wissensmagazin mit Science-News aus – 5 ore fa
Eine erstaunliche Konzentration von Dinosaurierfußspuren haben Geologen an der Grenze zwischen Arizona und Utah entdeckt. Vor rund 190 Millionen Jahren eine


Other links: (update on 2008-10-21 11:27 Italy)

CBS News

Geologists discover `dinosaur dance floor’
The Associated Press – 1 ora fa
SALT LAKE CITY (AP) – Geologists say they have discovered prehistoric animal tracks so densely packed on a 3/4-acre site that they’re calling it a “dinosaur dance floor.” The site along the Arizona-Utah state line offers a rich new set of clues about
U. geologists discover dinosaur stomping ground Salt Lake Tribune
Dinosaur Dance Floor’ FOXNews
Discovery Channel – Science Daily (press release) – Discover Magazine
e altri 215 articoli simili »

Rock records dino ‘dance floor’
BBC News – 17 ore fa
Scientists have identified an amazing collection of dinosaur footprints on the Arizona-Utah border in the US. There are so many prints – more than 1000
Geologists discover ‘dinosaur dancefloor’ in remote American
Daily Mail – 39 minuti fa
By Claire Bates Scientists have likened the wealth of tracks and tail-drag marks on the three-quarter acre site to a crowded ‘dinosaur dance floor.


Other links in Italiano: (update on 2008-10-21 18:05 Italy)

La Repubblica
ASCA – Agenzia Stampa Quotidiana Nazionale – 22 minuti fa
(ASCA) – Roma, 21 ott – Un gruppo di geologi dell’Utah ha scoperto un’area a densissima concentrazione di impronte di 190 milioni di anni fa lasciate sulle
“Sembra una pista da ballo” La Repubblica
e altri 2 articoli simili »
La Repubblica – 17 ott 2008
I dinosauri utilizzavano le lunghe creste ossee sulla testa per produrre suoni musicali con cui comunicavano tra di loro: e’ la nuova teoria degli


Original Article:


Volume 23, Issue 10 (October 2008), pag 700

A Wet Interdune Dinosaur Trampled Surface in the Jurassic Navajo Sandstone, Coyote Buttes, Arizona: Rare Preservation of Multiple Track Types and Tail Traces

Winston M. Seiler and Marjorie A. Chan

ottobre 20, 2008 Posted by | - R. Dinosauri, 2 Jurassic / Giurassico, America Northern, Articolo sc. di riferimento, Italiano (riassunto), Lang. - German, Lang. - Italiano, P - Impronte, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 commento

2008-10-17 – Utah, Usa: Nuovo “cimitero di dinosauri” (“Dinosaur graveyard”, tracks, “Gnatalie”, Deltapodus)

Nel nuovo cimitero dei dinosauri nello Utah meridionale, studiato da Luis Chiappe, sorprendentemente vi sono impronte e resti fossili sia del Giurassico che del Cretaceo.

Tra i primi, datati intorno a 145 milioni di anni fa, vanno annoverati un nuovo sauropode chiamato informalmente “Gnatalie”, e impronte di Stegosauro finora rinvenute solo in Europa (Deltapodus).

Tra i resti del Cretaceo vi sono invece impronte di Sauropodi, Teropodi e Ornitopodi.


‘Dinosaur graveyard’ found in southeast Utah

A 150-million-year-old sauropod skeleton is the centerpiece of the finds from the Jurassic and Cretaceous periods, discovered by a Los Angeles team.
By Thomas H. Maugh II, Los Angeles Times Staff Writer
9:25 AM PDT, October 17, 2008
Los Angeles researchers have discovered a “dinosaur graveyard” in southeastern Utah that is yielding a wealth of fossilized animals and footprints from the Jurassic and Cretaceous periods.

The centerpiece of the new finds is the well-preserved skeleton of a 150-million-year-old sauropod — a long-necked herbivore — that researchers have named “Gnatalie” because the scientists were “eaten alive” by gnats while they were excavating it earlier this year.

The team has so far excavated only part of the fossilized skeleton, which they estimate to be about 50 feet long. “It’s big and takes a lot of time,” said paleontologist Luis Chiappe, director of the Dinosaur Institute and the Natural History Museum of Los Angeles County.

Gnatalie was found in the remains of what was once a big riverbed and is now a light-colored stratum on the face of an exposed cliff. Nearby in the bed were the disarticulated remains of other sauropods and meat-eating dinosaurs, including the five-foot-long femur of a brachiosaur.

On the ridgeline of the cliff, the team found a large number of footprints preserved in sandstone. Surprisingly, one set of prints from the Jurassic era, which ended about 145 million years ago, prints of a sauropod were found near tracks of carnivorous theropods and herbivorous ornithopods from the early Cretaceous period, which ended about 65 million years ago.

Most stunning of all, to Chiappe, were the three-toed prints of a European stegosaur, named  “Deltapodus tracks have never been found in North America,” he said.

Chiappe and his staff, led by Doug Goudreau and Aisling Farrell, expect to spend at least another decade excavating the site.

The finds will be the centerpiece of an exhibit at the Natural History Museum of Los Angeles County that will open in 2011, he said.

A renovation of the dinosaur exhibit is part of the museum’s $84-million project to restore and seismically strengthen its original 1913 Beaux-Arts-inspired building.



other links (updated on 2008-10-18 11:48 Italy):

‘Dinosaur graveyard’ found in southeast Utah
Los Angeles Times – 44 minuti fa
A 150-million-year-old sauropod skeleton is the centerpiece of the finds from the Jurassic and Cretaceous periods, discovered by a Los Angeles team.
No visas required for six countries
Boston Globe – 3 ore fa
President Bush, trying to eliminate a major source of contention with allied nations, announced yesterday that the United States is rescinding visa
UPI NewsTrack Health and Science News
United Press International – 6 ore fa
LOS ANGELES, Oct. 17 (UPI) — Researchers said a dinosaur graveyard discovered in Utah holds a wealth of fossils from the Jurassic and Cretaceous periods.
Sauropod found in dinosaur graveyard
United Press International – 8 ore fa
LOS ANGELES, Oct. 17 (UPI) — Researchers said a dinosaur graveyard discovered in Utah holds a wealth of fossils from the Jurassic and Cretaceous periods.
Willow Plants Cleaning Up Contamination (press release) – 6 ore fa
(Source: United Press International)Researchers said 23000 willow plants are helping clean up a 164000-gallon underground fuel leak at a US Army base.

ottobre 17, 2008 Posted by | - Ornitopodi, - R. Dinosauri, - Sauropodi, - Teropodi, 1 Cretaceo, 2 Jurassic / Giurassico, America Northern, Italiano (riassunto), Musei, P - Impronte, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , , , , , , , , , | Lascia un commento

Un nuovo “giacimento” di dinosauri scoperto nello Utah

Dal sito del National geographic (link)

“Amazing” Dinosaur Trove Discovered in Utah

Brian Handwerk
for National Geographic News

June 17, 2008


Crowded with dinosaurs, petrified trees, and other prehistoric treasures, an ancient riverbed in Utah is surprising scientists.

The discovery sheds new light on a Jurassic landscape dominated by dinosaur giants that lived 145 to 150 million years ago (prehistoric time line).

In just three weeks of work on federal land near Hanksville, Utah, paleontologists say they unearthed at least two meat-eating dinosaurs, a probable Stegosaurus, and four sauropods—long necked, long-tailed plant-eaters that could reach 130 feet (40 meters) long, making them the largest animals ever to have walked the Earth.

“So far [the paleontologists] have found not only scattered bones but partial and complete skeletons. It’s really amazing,” said Scott Foss, a paleontologist in the Bureau of Land Management’s (BLM’s) Salt Lake City office.

Big Sexy Dinosaurs

Some BLM employees and many locals had known that there were dinosaur bones to be found near Hanksville. But the recent dig led by scientists from the Burpee Museum of Natural History in Rockford, Illinois, was still a shocker.

“Nobody anticipated the scale or the scope of what was there. Once they started excavating, they realized that the magnitude was far more than they had expected,” Foss said.

“About two weeks ago they notified us that this was pretty big and we’d better come and take a look.”

The site, now known as the Hanksville-Burpee Quarry, is part of the Morrison formation. “[The formation is] where all the big sexy dinosaurs that we grew up learning about are most commonly found,” Foss said.

Matthew Bonnan, of Western Illinois University, said, “In the late Jurassic you had the largest animals that ever walked the Earth.

“The sauropods sort of reached their zenith of size at this point,” added Bonnan, who had just returned from the dig site.

(Related: “Giant Duck-Billed Dino Unearthed in Utah” [October 3, 2007].)

Riverbed Graveyard Uncovered

Though the Hanksville-Burpee Quarry today is high and dry, it appears to have once been at a bend in a large, long-gone river.

A bar or other river feature likely collected the corpses of dinosaurs and other animals that died upstream and were washed down during high-water events over several centuries. The result is a logjam of fossilized bones.

The site’s sandstone also encases freshwater clams, petrified trees, and other preserved matter. “There is potential that there could be burrows that contain fossil mammals. We have petrified logs—a whole group of things that I think are going to tell us something very detailed about this environment,” Bonnan said.

(Related: “Ancient Mammal Relative Dug Burrows in Antarctica?” [June 9, 2008].)

The late Jurassic has been studied intensively for more than a century, yet some key questions linger.

“The big open question that remains is the environment in which the Morrison fauna and flora existed,” said Hans-Dieter Sues, associate director for research and collections at the Smithsonian’s National Museum of Natural History in Washington, D.C.

Sues has received funding from the National Geographic Society’s Committee for Research and Exploration.

Early geologists imagined the Morrison-formation region as a vast swamp, the imagined prime real estate for all those sauropods.

“But later geologists argued that the Morrison was deposited in a dry environment with just some large bodies of water,” said Sues, who is not involved with the Hanksville-Burpee dig.

New Look at Familiar Dinos?

Whatever mysteries the new site may hold, it is unlikely to produce any new dinosaur species, Sues said.

“Except for some really small dinosaurs—including possible bird relatives/precursors—or a good skeleton of the giant Brachiosaurus, there is going to be little that is newsworthy regarding Morrison dinosaurs,” he said.

“The big discoveries to be made lie with other groups of Morrison animals, such as flying reptiles and mammals, which are still mostly known from very fragmentary remains.”

But team member Bonnan hopes the Hanksville-Burpee will eventually rival Utah’s other major Jurassic fossil troves—Dinosaur National Monument and the Cleveland-Lloyd Dinosaur Quarry.

“Even if we don’t find anything new in terms of species, we’re looking at old bones with new eyes and new technologies,” he said.

“In the old days it was more about finding the ‘biggest, baddest, bestest’ dinosaurs, and a museum might have just cherry-picked those best specimens.

“Now there is more interest in the fossil assemblage—what does it tell you about the environment?”

The site will close for the season on Friday. But scientists are already anxiously awaiting the resumption of excavations next summer.

“It will take years to understand the real potential, or how big this site really is,” BLM’s Foss said. “But there is something there worth taking a really good look at.”

giugno 18, 2008 Posted by | - R. Dinosauri, - Sauropodi b, 2 Jurassic / Giurassico, America Northern, P - Ritrovamenti fossili, Paleontology / Paleontologia | , , , , , , , , | Lascia un commento