Giant Clawed Dinosaur Unearthed in Utah Desert
July 14, 2009 — A multi-institutional team of scientists this week reports the discovery of a giant new dinosaur in Utah, Nothronychus graffami, which stood 13 feet tall and had nine-inch-long hand claws that looked like scythes.
Its skeleton, described in the current issue of Proceedings of the Royal Society B, represents the most complete remains ever excavated of a therizinosaur, meaning “reaper lizard.” It is one of only three such dinosaurs ever found in North America.
Lead author Lindsay Zanno told Discovery News that therizinosaurs, including the new Utah species, “are unusual in that they have small heads with a keratinous beak at the front of the mouth — the same material as the beak of modern birds — and small leaf-shaped teeth.”
“Their bellies are proportionally enormous, supporting large guts,” added Zanno, who is a researcher in the Department of Geology at The Field Museum. “They have greatly enlarged claws on their hands, short legs and tails, and four-toed feet.”
Therizinosaurs are theropod predatory dinosaurs, a group that includes the legendary Tyrannosaurus rex. The newly discovered 92.5-million-year-old Utah dinosaur was no lightweight either. As Zanno said, “You wouldn’t want to run into this guy in a dark alley.” But its teeth, beak, gut and other anatomical characteristics suggest it was an omnivore that mostly feasted on plants.
Co-author David Gillette, curator of paleontology at the Museum of Northern Arizona, told Discovery News the formidable-looking claws on Nothronychus graffami probably weren’t used to kill other large animals, but instead might have tackled “digging into termite mounds, mucking on the bottom of a lake or pond like a goose or moose, and raking leaves into its mouth from a mangrove forest like a ground sloth.”
To better understand the dietary evolution of theropods, the researchers studied information on 75 other species within this group. They determined therizinosaurs experienced an early evolutionary split from the Maniraptora, which includes modern birds and their closest extinct relatives. One such relative was Velociraptor, a carnivore that probably kicked prey to death with its large hind foot claws.
The new Utah dinosaur therefore suggests that “iconic predators like Velociraptor, one of the dinosaurian villains in the movie Jurassic Park — may have evolved from less fearsome plant-eating ancestors,” according to the scientists.
Since the very meat-loving Velociraptor emerged some 20 million years after plant-chomping Nothronychus graffami, it’s now thought that some dinosaurs might have first been carnivores that evolved into omnivores or herbivores, which re-evolved back into meat-eaters.
Paleontologists aren’t sure why some dinosaur lineages may have see-sawed back and forth with their diets.
“Our current thoughts are that in gaining the ability to eat more than just meat, maniraptorans may have been able to invade new niches in the ecosystem that were unavailable to them before,” Zanno said. “In other words, they may have been able to find a new way of living in the ecosystem and new resources to exploit that gave them an advantage and allowed them to diversify into new forms.”
Aside from what it reveals about dinosaur diets, the new Utah species is significant because of where it was found: in marine sediments that would have been between 60 and 100 miles away from the closest shoreline. The ancient sea is now part of a desert. Merle Graffam, a member of the excavation team, found the dinosaur while searching for sea-dwelling animals. The dinosaur was named after him.
“A big mystery is how this animal — either alive or as a carcass — could get so far out to sea without being torn apart by predators and scavengers,” Gillette said. “This ecosystem had at least five species of plesiosaurs and many sharks and predatory, scavenging fish.”
He added, “Maybe (the dinosaur) was stranded at sea and struggled for a few days before drowning and sinking to the bottom.”
Paul Heinrich, a research associate at the Louisiana Geological Survey, offers another explanation. He thinks such complete dinosaur skeletons recovered in seaways may have rafted out to open water on “floating islands” after storms.
The recovered Utah dinosaur’s remains are now on public display at the Museum of Northern Arizona. The exhibit, Therizinosaur: Mystery of the Sickle-Claw Dinosaur, will close in September before moving to the Arizona Museum of Natural History in Mesa.
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World’s Oldest Dinosaur Burrow Discovered In Australia
Posted on: Friday, 10 July 2009, 16:20 CDT | Related Video
Paleontologists have discovered the world’s oldest dinosaur burrows in Australia. The 106-million-year-old burrows are the first to be found outside of North America, and were much closer to the South Pole when they were created.
In total, three separate burrows have been discovered, the largest of which was about 6ft. long. Each burrow had a similar design and was just large enough to contain the body of a small dinosaur.
The discovery supports the theory that dinosaurs living in harsh, cold climates burrowed underground to survive.
The only other known dinosaur burrow was discovered in 2005 in Montana, and contained the bones of an adult and two young dinosaurs of a small new species called Oryctodromeus cubicularis. Two years after its discovery, scientists dated the burrow from 95 million years ago.
The older burrows in Australia were found by one of the researchers who made the original Montana discovery.
“Like many discoveries in paleontology, it happened by a combination of serendipity and previous knowledge,” said Anthony Martin of Emory University in Atlanta.
“In May 2006, I hiked into the field site with a group of graduate students with the intention of looking for dinosaur tracks. We did indeed find a few dinosaur tracks that day, but while there I also noted a few intriguing structures,” he told BBC News.
Martin returned to the site, known as Knowledge Creek about 150 miles from Melbourne, to study the structures in July 2007 and again in May of 2009.
He was astonished at what he found.
“I was scanning the outcrop for trace fossils, and was very surprised to see the same type of structure I had seen in Cretaceous rocks of Montana the previous year,” said Martin.
That original structure was the burrow of O. cubicularis.
“So to walk up to the outcrop and see such a strikingly similar structure, in rocks only slightly older, but in another hemisphere, was rather eerie,” Martin said.
Within the rock, which is part of the Otway group of rocks that have produced a large diversity of vertebrate fossils, Martin discovered three separate burrows less than 10 feet apart, two of which formed a semi-helix twisting down into the rock.
The largest and best-preserved burrow turns twice before ending in a larger chamber. Dubbed tunnel A, it is more than 6 feet in length. Martin calculates that an animal weighing around 22 pounds would have created each burrow. Twisting burrows can help keep predators at bay and provide a steady temperature and humidity environment.
Alligators, aardwolves, coyotes, gopher tortoises and striped hyenas are among the modern animals that make such burrows.
Although Martin isn’t sure which species of dinosaur made the burrows, he noted how similar their designs are to the burrow created by O. cubicularis.
A number of small ornithopod dinosaurs, which stood upright on their hind legs and were about the size of a large iguana, were believed to have lived in the area during the same time in the Cretaceous period.
Martin has ruled out a number of other sources that could have created the burrows.
The fact dinosaurs created them makes sense, he said.
Australian researchers first proposed two decades ago that some dinosaurs might have created burrows to survive harsh climates they couldn’t escape from by migrating.
“It gives us yet another example of how dinosaurs evolved certain adaptive behaviors in accordance with their ecosystems,” Martin said.
“Polar dinosaurs in particular must have possessed special adaptations to deal with polar winters, and one of their behavioral options was burrowing. It provides an alternative explanation for how small dinosaurs might have overwintered in polar environments.”
Martin hopes that paleontologists will be on the look out for dinosaur burrows, and for dinosaurs that are physically adapted to burrowing into soil.
The findings were published in the journal Cretaceous Research.
Image 1: Drawing by James Hays, Fernbank Museum
Image 2: Following his Montana discovery of the first trace fossil of a dinosaur burrow, Emory University paleontologist Anthony Martin has found evidence of older, polar dinosaur burrows in Victoria, Australia.
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Source: redOrbit Staff & Wire Reports
Lo studio al microscopio elettronico delle tracce sui denti di alcuni Adrosauri ne rivelano la complessa tipologia di masticazione.
Dino tooth sheds new light on ancient riddle
Scientists discover major group of dinosaurs had unique way of eating unlike anything alive today
|IMAGE: These are teeth from the lower jaw of a hadrosaur, Edmontosaurus, showing its multiple rows of leaf-shaped teeth. The worn, chewing surface of the teeth is towards the top.Click here for more information.|
Microscopic analysis of scratches on dinosaur teeth has helped scientists unravel an ancient riddle of what a major group of dinosaurs ate- and exactly how they did it!
Now for the first time, a study led by the University of Leicester, has found evidence that the duck-billed dinosaurs- the Hadrosaurs- in fact had a unique way of eating, unlike any living creature today.
Working with researchers from the Natural History Museum, the study uses a new approach to analyse the feeding mechanisms of dinosaurs and understand their place in the ecosystems of tens of millions of years ago. The results are published today in the Proceedings of the National Academy of Sciences.
Palaeontologist Mark Purnell of the University of Leicester Department of Geology, who led the research, said: “For millions of years, until their extinction at the end of the Cretaceous, duck-billed dinosaurs – or hadrosaurs – were the World’s dominant herbivores. They must have been able to break down their food somehow, but without the complex jaw joint of mammals they would not have been able to chew in the same way, and it is difficult to work out how they ate. It is also unclear what they ate: they might have been grazers, cropping vegetation close to the ground – like today’s cows and sheep – or browsers, eating leaves and twigs – more like deer or giraffes. Not knowing the answers to these questions makes it difficult to understand Late Cretaceous ecosystems and how they were affected during the major extinction event 65 million years ago.
|IMAGE: These are teeth from the upper jaw of a hadrosaur, Edmontosaurus. The specimen was molded and coated with gold for examination using a Scanning Electron Microscope to give high power…Click here for more information.|
“Our study uses a new approach based on analysis of the microscopic scratches that formed on hadrosaur’s teeth as they fed, tens of millions of years ago. The scratches have been preserved intact since the animals died. They can tell us precisely how hadrosaur jaws moved, and the kind of food these huge herbivores ate, but nobody has tried to analyse them before.”
The researchers say that the scratches reveal that the movements of hadrosaur teeth were complex and involved up and down, sideways and front to back motion. According to Paul Barrett palaeontologist at the Natural History Museum “this shows that hadrosaurs did chew, but in a completely different way to anything alive today. Rather than a flexible lower jaw joint, they had a hinge between the upper jaws and the rest of the skull. As they bit down on their food the upper jaws were forced outwards, flexing along this hinge so that the tooth surfaces slid sideways across each other, grinding and shredding food in the process”.
The scratch patterns provide confirmation of a theory of hadrosaur chewing first proposed 25 years ago, and provides new insights into their ecology, say the researchers.
The research also sheds light on what the dinosaurs ate. Vince Williams of the University of Leicester said: “Although the first grasses had evolved by the Late Cretaceous they were not common and it is most unlikely that grasses formed a major component of hadrosaur diets. We can tell from the scratches that the hadrosaur’s food either contained small particles of grit, normal for vegetation cropped close to the ground, or, like grass, contained microscopic granules of silica. We know that horsetails were a common plant at the time and have this characteristic; they may well have been an important food for hadrosaurs”.
|IMAGE: This is a highly magnified Scanning Electron Microscope view of the surface of one of the hadrosaur teeth, showing the scratches created about 67 million years ago by tooth movements…Click here for more information.|
One of the big surprises of this study is that so much information about such large animals can be gleaned from such a tiny patch of tooth. “By looking at the pattern of scratches in an area that is only about as wide as a couple of human hairs we can work out how and what these huge herbivores were eating” notes Williams. “And because we can analyse single teeth, rather than whole skeletons, the technique has the potential to tell us a lot more about dinosaur feeding and the ecosystems in which they lived.”
For interviews contact:
Dr Mark A. Purnell
Reader in Geology
Department of Geology
University of Leicester
Leicester LE1 7RH
Tel +44 116 252 3645
Fax +44 116 252 3918
1. The erroneous idea that all dinosaurs could chew is so widely accepted that the memorable ‘Chewits’ advertising campaigns of the 1980s were based on the idea. Note that the dinosaur shown in the adverts is not a hadrosaur:
2. The paper “Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding” by Vincent S. Williams, Paul M. Barrett and Mark A. Purnell is published in the Proceedings of the National Academy of Sciences (online Early Edition).
3. Vince Williams and Mark Purnell are at the University of Leicester, UK; Paul Barrett is at the Natural History Museum, London, UK. A pdf of the paper is available from Mark Purnell: firstname.lastname@example.org
4. Winner of Visit London’s 2008 Kids Love London Best Family Fun Award, the Natural History Museum is also a world-leading science research centre. Through its collections and scientific expertise, the Museum is helping to conserve the extraordinary richness and diversity of the natural world with groundbreaking projects in 68 countries
5. To arrange an interview with Paul Barrett please contact: Claire Gilby, Senior Press Officer, Natural History Museum, Tel: 020 7942 5106 Email: email@example.com (not for publication)
6. Following images can be obtained from University of Leicester firstname.lastname@example.org
- Teeth from the lower jaw of a hadrosaur, Edmontosaurus, showing its multiple rows of leaf-shaped teeth. The worn, chewing surface of the teeth is towards the top. Credit: Vince Williams, University of Leicester.
- Teeth from the upper jaw of a hadrosaur, Edmontosaurus. The specimen was moulded and coated with gold for examination using a Scanning Electron Microscope to give high power magnification of the microscopic scratches. Credit: Vince Williams, University of Leicester.
- Highly magnified Scanning Electron Microscope view of the surface of one of the hadrosaur teeth, showing the scratches created about 67 million years ago by tooth movements and feeding. The small black boxes show the areas, each less than half a millimetre wide, in which scratches were analysed. Credit: Vince Williams, University of Leicester.
- Artists reconstruction of a hadrosaur eating; analysis of tooth wear indicates grazing low growing silica rich plants, like horsetails, was more likely than browsing on bushes. Contact email@example.com for image.
Hadrosaur fact file
This study is based on Edmontosaurus: Lived USA and Canada 65-68 million years ago; Length up to 13 m, weight up to 3 tonnes; One of the most abundant dinosaurs of its time; Known from many complete skeletons, including several mummies with skin impressions and gut contents preserved.
Notes for editors:
Fossili di 3 grandi dinosauri scoperti in Australia
SYDNEY (Reuters) – Fossili di tre nuove specie di dinosauri sono stati scoperti in Australia, di cui quello di un carnivoro più grande del Velociraptor dei film di Jurassic Park, lasciando intendere che l’Australia potrebbe avere un passato preistorico più complesso di quanto si pensi.
I tre fossili, due di erbivori e uno di un carnivoro — i primi resti di grandi dinosauri rinvenuti dal 1981 — sono stati trovati nel Queensland e risalgono al Cretaceo, 98 milioni di anni fa.
“Questa scoperta ci fa conoscere non solo due affascinanti giganti dal collo lungo del continente australiano antico, ma anche il nostro primo grande predatore” ha detto oggi il paleontologo John Long, del Museo Victoria.
Il paleontologo Ben Kear dell’Università La Trobe di Melbourne ha detto che la scoperta apre la strada a nuovi studi sui dinosauri australiani e il loro habitat.
“L’Australia è una delle grandi risorse poco sfruttate per la comprensione della vita nel periodo dei dinosauri”, ha detto Kear. “Questo … farà sicuramente crescere l’interesse nelle finora incomplete ma rilevanti scoperte in questo continente”.
Triple Fossil Find Puts Australia Back On The Dinosaur Map
ScienceDaily (July 3, 2009) — Scientists have discovered three new species of Australian dinosaur discovered in a prehistoric billabong in Western Queensland.
Reporting on July 3 in the open-access, peer-reviewed journal, PLoS ONE, Scott Hocknull and colleagues at the Queensland Museum and the Australian Age of Dinosaurs Museum of Natural History describe the fossils of three new mid-Cretaceous dinosaurs from the Winton Formation in eastern Australia: two giant, herbivorous sauropods and one carnivorous theropod, all of which are to be unveiled in Queensland on July 3. The three fossils add to our knowledge of the Australian dinosaurian record, which is crucial for the understanding of the global paleobiogeography of dinosaurian groups.
Australia’s dinosaurian fossil record is extremely poor, compared with that of other similar-sized continents, such as South America and Africa. However, the mid-Cretaceous Winton Formation in central western Queensland has, in recent years, yielded numerous fossil sites with huge potential for the discovery of new dinosaurian taxa. Between 2006 and 2009, extensive excavations have yielded many well-preserved dinosaur fossils, as well as the remains of other contemporaneous fauna.
In a single, comprehensive, publication, Hocknull and colleagues describe the remains of three individual dinosaur skeletons, found during joint Australian Age of Dinosaurs Museum and Queensland Museum digs in two different sites in the Winton Formation. They represent three new genera and species of dinosaur: two giant herbivorous sauropods and a carnivorous theropod.
The carnivore, named by the authors on the paper Australovenator wintonensis (nicknamed “Banjo”) is the most complete meat-eating dinosaur found in Australia, to date and sheds light on the ancestry of the largest-ever meat-eating dinosaurs, the carcharodontosaurs, a group of dinosaurs that became gigantic, like Giganotosaurus.
“The cheetah of his time, Banjo was light and agile,” said lead author Scott Hocknull. “He could run down most prey with ease over open ground. His most distinguishing feature was three large slashing claws on each hand. Unlike some theropods that have small arms (think T. rex), Banjo was different; his arms were a primary weapon.
“He’s Australia’s answer to Velociraptor, but many times bigger and more terrifying.”
The skeleton of Australovenator solves a 28-year-old mystery surrounding an ankle bone found in Victoria, which was originally classified as a dwarf Allosaurus, although this classification remained controversial until the discovery of Australovenator—the researchers are now able to confirm that the ankle bone belonged to the lineage that led to Australovenator.
The two plant-eating theropods, named Witonotitan wattsi (“Clancy”) and Diamantinasaurus matildae (“Matilda”), are different kinds of titanosaur (the largest type of dinosaur ever to have lived). While Witonotitan represents a tall, gracile animal, which might have fitted into a giraffe-like niche, the stocky, solid Diamantinasaurus represents a more hippo-like species.
All three dinosaurs are nicknamed after characters from a world-famous, Australian poet. Banjo Patterson composed Waltzing Matilda in 1885 in Winton, where the song was also first performed (and where the fossils were discovered). Waltzing Matilda is now considered to be Australia’s national song.
In a quirky twist of fate, the song Waltzing Matilda describes the unfortunate demise of a swag-man, who steals a jumbuck (sheep) but is driven to leap into a billabong (an Australian word for a small oxbow lake) to avoid being captured by the police. He ends up drowning in the billabong alongside the stolen sheep.
Banjo and Matilda were found buried together in what turns out to be a 98-million-year-old billabong. Whether they died together or got stuck in the mud together remains a mystery; however, echoing the song, both predator and possible prey met their end at the bottom of a billabong, 98 million years ago. This shows that processes that were working in the area over the last 98 million years are still there today. “Billabongs are a built-in part of the Australian mind,” said Hocknull, “because we associate them with mystery, ghosts and monsters.”
The finding and documentation of the fossils was a 100% Australian effort. Both Matilda and Banjo were prepared by Australian Age of Dinosaurs Museum thanks to thousands of hours of volunteer work and philanthropy.
“This is the only place in Australia where you can come off the street and be taught to be a palaeontologist and find, excavate and prepare your own part of Australian natural history,” said Hocknull. The dinosaurs will now be part of a museum collection and this effort will enable future generations of scientists to be involved in a new wave of dinosaur discoveries and to bring the general public in touch with their own natural heritage.”
This collaborative effort links closely with PLoS ONE’s philosophy of making science freely accessible to the general public. “One of my major motivations for submitting to PLoS ONE was the fact that my research will reach a much wider community, including the hundreds of volunteers and public who gave their time and money to the development of natural history collections,” said Hocknull. “They are the backbone of our work (excuse the pun) and they usually never get to see their final product because they rarely subscribe to scientific journals.”
All three new taxa, along with some fragmentary remains from other taxa, indicate a diverse Early Cretaceous sauropod and theropod fauna in Australia, and the finds will help provide a better understanding of the Australian dinosaurian record, which is, in turn, crucial for the understanding of the global palaeobiogeography of dinosaurian groups.
The authors agree that even though hundreds of bones have already been found at the site, these fossils are just the tip of the iceberg. “Many hundreds more fossils from this dig await preparation and there is much more material left to excavate,” they said. Australian Age of Dinosaurs Museum and Queensland Museum staff and volunteers will continue to dig at this and other sites in 2010.
The fossils will be unveiled at the Australian Age of Dinosaurs Museum of Natural History in Queensland, Australia, July 3 by Anna Bligh, the Premier of Queensland. Stage 1 of the museum, a non-profit, volunteer-driven, science initiative that aims to bring Australian dinosaurs to the world, will also be opened by Ms Bligh on July 3.
- Scott A. Hocknull, Matt A. White, Travis R. Tischler, Alex G. Cook, Naomi D. Calleja, Trish Sloan, David A. Elliott. New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton, Queensland, Australia. PLoS ONE, 2009; 4 (7): e6190 DOI: 10.1371/journal.pone.0006190
2009-06-20 – Spagna, Teruel: trovato nuovo ornitopode (Spain, new Ornithopod) (Espana, nuevo ornitópodo)
Paleontologists of Dinópolis Foundation have found the back leg of new a dinosaur ornithopod of small size near a vertebra and a tooth of the “Turiasaurus riodevensis”. These remains are been founded in the deposit going back to 145 million years ago of Barrihonda-El Chimney of Riodeva, in Teruel , Spain.
El nuevo ornitópodo de Teruel
Pata trasera del ornitópodo encontrado en Teruel. / Fundación Dinópolis
- Hallan la pata trasera de un nuevo dinosaurio de pequeño tamaño
- También han localizado una vértebra y un diente del ‘Turiasaurus riodevensis’
La pata de un nuevo dinosaurio, seguramente un ornitópodo de hace unos 145 millones de años, es el último tesoro paleontológico encontrado en el yacimiento de Barrihonda-El Humero de Riodeva, en Teruel, en las excavaciones de este año de la Fundación Dinópolis.
Junto con este fósil, ya han aparecido una vértebra y un diente más del gigantesco ‘Turiasaurus riodevensis’, considerado el más grande de Europa, cuyo esqueleto cada vez está más completo.
El hallazgo de la pata trasera del nuevo dinosaurio fue una auténtica sorpresa, como explica Luis Alcalá, director de la Fundación Dinópolis: “Apareció el primer día de las excavaciones en el yacimiento, que es una explanada del tamaño de un campo de baloncesto. Estaban limpiando la zona cuando toparon con el fósil, a unos cuatro metros del ‘Turiasaurus’. Enseguida vimos que era otro dinosaurio nuevo, del grupo de los ornitópodos, pero aún no sabemos de qué especie”, explica el paleontólogo.
Los ornitópodos eran dinosaurios de tamaño pequeño, unos cinco metros incluida la cola, que comían plantas y andaban a cuatro patas. No tenían armadura, ni cuernos ni colmillos; posiblemente las únicas defensas con que contaron fueron su pico grande y fuerte y la cresta (aunque solo algunos).
A pocos metros de este ejemplar, se ha encontrado una vértebra del gigante de Riodeva, así como otro diente. Completar lo más posible su esqueleto es el objetivo prioritario del proyecto de la excavación, cuando ya se tiene un 45%. También han salido a la luz restos de carnívoros, entre ellos uno de grandes dimensiones.
A falta de realizar un exhaustivo estudio de los últimos huesos, el director de la Fundación plantea que podría haber habido una avalancha o algún otro suceso natural que provocó la muerte simultánea de varios dinosaurios, debido a la gran acumulación de huesos que hay en el mismo sitio.
Hace unas semanas, los investigadores confirmaron que animales carnívoros, alguno de grandes dimensiones, habían devorado a ‘Turiasaurus’, en cuyos restos de la cadera se identificaron perforaciones hechas por las mordeduras.
Las excavaciones en este yacimiento continuarán hasta el 20 de julio, si sigue este ritmo de hallazgos. “No podemos sacar más fósiles de los que podemos estudiar en los ocho meses siguientes. Y también hay que preparar el material”, comenta Alcalá.
Hasta ahora, el yacimiento de Barrihonda-El Humero está siendo una mina. Junto con el gigante de Europa y varios carnívoros, se había encontrado un estegosaurio, y la lista aumenta ahora con el nuevo ornitópodo.
Rosa M. Tristán | Madrid
per informazioni in italiano vedi:
New dinosaur gives bird wing clue
The Limusaurus fossil sits among small crocodile fossils
A new dinosaur unearthed in western China has shed light on the evolution from dinosaur hands to the wing bones in today’s birds.
The fossil, from about 160 million years ago, has been named Limusaurus inextricabilis.
The find contributes to a debate over how an ancestral hand with five digits evolved to one with three in birds.
The work, published in Nature, suggests that the middle three digits, rather than the “thumb” and first two, remain.
Theropods – the group of dinosaurs ancestral to modern birds and which include the fearsome Tyrannosaurus rex – are known for having hands and feet with just three digits.
It has been a matter of debate how the three-fingered hand developed from its five-fingered ancestor. Each digit among the five was composed of a specific number of bones, or phalanges.
Palaeontologists have long argued that it is the first (corresponding to the thumb), second, and third fingers from that ancestral hand that survived through to modern birds, on grounds that the three fingers in later animals exhibit the correct number of phalanges.
However, developmental biologists have shown that bird embryos show growth of all five digits, but it is the first and fifth that later stop growing and are reabsorbed.
The remaining three bones fuse and form a vestigial “hand” hidden in the middle of a bird’s wing.
James Clark of George Washington University in Washington DC and Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing hit an palaeontologist’s gold mine in the Junggar Basin of northwestern China.
Previous digs have unearthed the oldest known fossil belonging to the tyrannosaur group and the oldest horned dinosaur among several others.
This time, the ancient mire has yielded a primitive ceratosaur, a theropod that often had horns or crests, many of whom had knobbly fingers without claws.
“It’s a really weird animal – it’s got no teeth, had a beak and a very long neck, and very wimpy forelimbs,” Professor Clark told BBC News.
“Then when we looked closely at the hand, we noticed it was relevant to a very big question in palaeontology.”
The fossil has a first finger which is barely present, made up of just one small bone near the wrist. The fifth finger is gone altogether.
It is a fossil that appears to offer a snapshot of evolution, proving that the more modern three-fingered hand is made up of the middle digits of the ancestral hand, with the outer two being shed.
The third finger is made up of the four phalange bones that the second should have, and it is presumed that the second would lose one bone to become like the first finger that was missing in the fossil.
This process of shifting patterns of gene expression from one limb or digit to another is known as an “identity shift”, and was again caught in the act – making the conflicting theories of bird hand origin suddenly align.
“This is amazing – it’s the first time we’ve seen this thing actually starting to disappear,” Jack Conrad, a palaeontologist at the American Museum of Natural History, told BBC News.
“There’s been this fundamental rift – there was no way to make peace between the good data we were seeing from the developmental biologists and the palaeontological evidence that showed with every fossil we found we were seeing [fingers] one, two and three.”
FOXNews - 17/giu/2009
NEW DINOSAUR: Fossil Fingers Solve Bird Wing Mystery? National Geographic
Con un po` di ritardo ecco il post su una notizia “eccezonale”.
Un osso ritrovato in sedimenti di origine marina nel Cenomaniano della Sicilia e stato identificato come appartenente a un dinosauro (il quarto ritovato in Italia).
Per info piu` dettagliate: Blog – Teropoda
Garilli, V, et al. “First dinosaur bone from Sicily identified by histology and its palaeobiogeographical implications.” Neues Jahrbuch für Geologie und Paläontologie 252.2 (2009):207-216.
Maryland Science Center to hatch ‘Chinasaurs’
More than 20 skeletons, other fossils will be on view at Inner Harbor museum
If the Maryland Science Center has anything to say about it, Baltimoreans will soon think of China as the home of more than chopsticks, serious ping pong players and the giant panda. By the end of the summer, it should also be known as the land of Mamenchisaurus, Szechuanosaurus and Monolophosaurus, not to mention Tuojiangosaurus and Psittacosaurus.
Through Labor Day, dinosaurs from China will be invading Baltimore. And the folks at the Inner Harbor science center couldn’t be happier.
“Some of these have not been found anywhere else in the world,” says Van Reiner, the center’s president and chief executive.
“The dinosaur aficionados of this area are certainly going to see examples of dinosaurs they won’t see anywhere in the United States.”
Chinasaurs: Dinosaur Dynasty, opening Saturday in 7,000 square feet of exhibit space on the museum’s second floor, features 20 skeletons, all of thunder lizards unearthed on the Chinese mainland. Many have never before been displayed outside their native land (“The Chinese have been very protective of their finds,” Reiner says), and most are of prehistoric animals rarely mentioned in scientific textbooks.
That alone shouldn’t be surprising. The rate of dinosaur discoveries has been climbing exponentially in recent years, says Reiner. “Just when they thought they had identified all the dinosaurs, they hadn’t,” he says. “The estimate is that they’ve identified less than 10 percent.”
What might be surprising to dino-philes, as well as thrilling to even casual fans, is the range of fossils on display – from a 10-inch, astonishingly well-preserved Keichousaurus, looking like someone had carefully placed it between two sheets of rock, to a 70-foot-long skeleton of Mamenchisaurus, a creature with the longest neck of all the dinosaurs (think of a giraffe stretched out low to the ground, and you’ll get the idea).
Some of the names should ring familiar. There’s a Protoceratops, famous for being the first dinosaur whose eggs were unearthed (they actually turned out to be Oviraptor eggs, but that discovery didn’t come until nearly 70 years later). And there are several Velociraptors, the herding predators made famous in Jurassic Park.
But most of the names will prove not only unfamiliar, but tongue-twisting. Some, like Szechuanosaurus, sound like they’d be at home in a Chinese restaurant. Others, like Confuciusornis and Tuojiangosaurus (which translates to “two-river lizard”), readily betray their Asian origins.
There’s a skeleton of a Jinghanosaurus, its head peering around a wall into another display. A feathered Caudipteryx, one of those winged creatures that clearly marks the connection between dinosaurs and birds, is captured in rock as though desperately trying to flap its wings one last time. Among the oddest-looking beasts on display is Pachycephalosaur, a relatively small dinosaur whose gigantic skull resembles a football helmet. For the record, scientists don’t believe the creatures head-butted one another, but rather that they would smack each other on the sides of the heads.
And if any of those names give you trouble, try asking around. Dino-philes are usually pretty good with their nomenclature.
“Every few years, you get a new generation of dinosaur fans,” says Brenda Lewis, the science center’s acting director of exhibits. “You get these 3- or 4-year-olds who can’t talk properly, but they can pronounce the names of every dinosaur they see.”
If you go
Chinasaurs opens Saturday at the Maryland Science Center, 601 Light St. Tickets are $14.95-$20.95. Call 410-685-5225 or go to mdsci.org.
Dinosaur Trail (Montana): il Sentiero dei Dinosauri compie 5 anni
Ci sono voluti almeno 150 milioni d’anni ed oggi il Dinosaur Trail nel Montana, celebra il suo quinto anniversario enumerando ben 15 località archeologiche, con musei e siti paleontologici, in ben 12 comunità dell’est e del centro del Montana.
Il Montana Dinosaur Trail è un percorso adatto a famiglie con bambini e ad appassionati di paleontologia: offre la possibilità di ammirare, toccare ed imparare tutto il mondo fossile esistente nel Montana, risalente ad oltre 75 fino a 150 milioni d’anni fa.
Ogni località lungo il Dinosaur Trail dispone di mostre con fossili o repliche di dinosauri trovati nelle specifiche zone. Tra gli esemplari, anche Leonardo – un dinosauro mummia – uno dei meglio conservati al mondo, in località Malta; il Peck Rex uno scheletro intero originale del famoso T-Rex a Fort Peck; la più grande collezione di dinosauri ritrovati negli Stati Uniti, presso la località di Bozeman, ed infine le prime ossa del cucciolo di dinosauro del Nord America a Bynum e lo scheletro di Anatotitan in mostra a Ekalala.
Nel 2008 almeno 267.000 turisti hanno incluso il Dinosaur Trail nel loro viaggio nel Montana provando l’esperienza di 15 siti ben strutturati. Un terzo di questi visitatori sono internazionali. Questo a riprova che il Dinosaur Trail è veramente un’attrattiva eccezionale!
Ma la cosa ancora più intrigante è la possibilità di acquistare un Montana Dinosaur Trail Prehistoric Passport per soli 5 $, acquistabile anche direttamente nel sito www.mtdinotrail.org. Solo 2 $ il costo aggiuntivo con ordine in internet.
Le attrattive e le località del DinoTrail:
Blaine County Museum, Chinook
Carter County Museum, Ekalaka
Fort Peck Field Station of Paleontology, Fort Peck
Fort Peck Interpretive Center, Fort Peck
Garfield County Museum, Jordan
Great Plains Dinosaur Museum and Field Station, Malta
H. Earl Clack Memorial Museum, Havre
Makoshika Dinosaur Museum, Glendive
Makoshika State Park, Glendive
Museum of the Rockies, Bozeman
Old Trail Museum, Choteau
Phillips County Museum, Malta
Rudyard Depot Museum, Rudyard
Two Medicine Dinosaur Center, Bynum
Upper Musselshell Museum, Harlowton
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