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.
Congratuazioni agli autori !!!
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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:
By NINIEK KARMINI – Jun 22, 2009
BANDUNG, Indonesia (AP) — Indonesian scientists are reconstructing the largest, most complete skeleton of a prehistoric giant elephant ever found in the tropics, a finding that may offer new clues into the largely mysterious origins of its modern Asian cousin.
The prehistoric elephant is believed to have been submerged in quicksand shortly after dying on a riverbed in Java around 200,000 years ago. Its bones — almost perfectly preserved — were discovered by chance in March when an old sand quarry collapsed during monsoon rains.
The animal stood four meters (13-feet) tall, five meters (16-feet) long and weighed more than 10 tons — closer in size to the woolly mammoth of the same period than to the great Asian mammals now on Earth.
Animal fossils are rare in the humid, hot climate of the equator because decomposition occurs extremely quickly.
Following a monthlong excavation, a team of seven paleontologists from the Geology Museum in Bandung, West Java, set the bones in plaster for the trip back to their office where they will be laboriously pieced back together.
“We believe from the shape of its teeth that it was a very primitive elephant,” but little else has been verified, said paleontologist Fachroel Aziz, who is heading a 12-strong skeletal reconstruction team.
Scientists agree it is the first time an entire prehistoric elephant skeleton has been unearthed since vertebrate fossil findings began to be recorded in Indonesia in 1863.
“It is very uncommon to discover a fossil like this in a tropical region like Indonesia,” said Edi Sunardi, an independent expert at Indonesia’s Pajajaran University in Bandung, West Java. “It apparently was covered by volcanic sediment that protected it from high temperatures, erosion and decay.”
The next challenge will be removing the delicate bones from their molds and joining them into a stable, upright structure, a process that experts said is already being hampered by a lack of funding, inadequate tools and poor expertise.
Indonesia, an emerging and impoverished democracy of 235 million people, cannot afford to allocate more than a token sum to its aging museums, even for projects that have the potential to advance knowledge about the origin of key native species.
Gert van den Berg, a researcher at Australia’s Wollongong University who helped dig up the skeleton, said tests are under way to determine its precise age and species, and that they will help provide details “about when the modern elephants evolved into what they are now.”
About 2,000 old elephant remains have been found across the island nation over the past 150 years, but never in such good condition, Aziz said.
“We want to exhibit it publicly because this is a spectacular discovery,” he said.
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
2009-06-15 – Mare del Nord: pescati resti di “Uomo di Neanderthal” (North Sea, Homo neanderthalensis)
SCIENZA: FOSSILE DEL MARE DEL NORD APPARTENEVA A UOMO NEANDERTHAL
(ASCA) – Roma, 15 giu – Un frammento di osso recuperato nelle acque del mare del Nord apparteneva ad un uomo di Neanderthal. Secondo quanto rende noto il sito web della Bbc, il primo ritrovamento del genere, e’ stato confermato dall’analisi degli isotopi del fossile, che risale a 60 mila anni fa ed e’ appartenuto ad un uomo la cui alimentazione era carnivora, caratteristiche specifiche dell’uomo di Neanderthal.
Il Mare del Nord e’ una delle aree piu’ ricche del pianeta per ritrovamenti di fossili di mammiferi, dovuto al fatto che nelle ere passate i livelli dell’acqua erano sostanzialmente piu’ bassi di quelli odierni con vaste zone di terraferma.
Qui sono stati ritrovati molti reperti di animali dell’era glaciale, come cavalli, renne, rinoceronti e mammuth.
Il frammento di osso frontale scoperto a Leiden, nei Paesi Bassi, e’ il primo conosciuto reperto umano ”arcaico” recuperato dalle acque del mare in tutto il mondo. Fu ritrovato fra resti di altri animali e manufatti di pietra a 15 chilometri al largo delle coste olandesi nel 2001. Gli studi sui reperti sono stati condotti dal professor Jean-Jacques Hublin, del Max Planck Institute for Evolutionary Anthropology di Leipzig, in Germania. ”Anche avendo un piccolo frammento di disposizione, possiamo ora sicuramente confermare la sua appartenenza ad un uomo di Neanderthal”, ha detto Hublin alla Bbc.
L’uomo di Neanderthal e’ vissuto nel periodo detto paleolitico, fra 130 mila e 25-30 mila anni fa in Europa, Africa e Asia
Sea gives up Neanderthal fossil
The fragment of skull belonged to a young adult male
Part of a Neanderthal man’s skull has been dredged up from the North Sea, in the first confirmed find of its kind.
Scientists in Leiden, in the Netherlands, have unveiled the specimen – a fragment from the front of a skull belonging to a young adult male.
Analysis of chemical “isotopes” in the 60,000-year-old fossil suggest a carnivorous diet, matching results from other Neanderthal specimens.
The North Sea is one of the world’s richest areas for mammal fossils.
But the remains of ancient humans are scarce; this is the first known specimen to have been recovered from the sea bed anywhere in the world.
For most of the last half million years, sea levels were substantially lower than they are today.
Significant areas of the North Sea were, at times, dry land. Criss-crossed by river systems, with wide valleys, lakes and floodplains, these were rich habitats for large herds of ice age mammals such as horse, reindeer, woolly rhino and mammoth.
Their fossilised remains are brought ashore in large numbers each year by fishing trawlers and other dredging operations.
According to Professor Chris Stringer, from London’s Natural History Museum, some fishermen now concentrate on collecting fossils rather than their traditional catch.
“There were mammoth fossils collected off the Norfolk and Suffolk coasts 150 years ago, so we’ve known for some time there was material down there that was of this age, or even older,” Professor Stringer, a museum research leader, told BBC News. Indeed, some of the fossil material from the North Sea dates to the Cromerian stage, between 866,000 and 478,000 years ago.
It had been “only a matter of time”, he said, before a human fossil came to light.
Professor Stringer added: “The key thing for the future is getting this material in a better context.
“It would be great if we could get the technology one day to go down and search (in the sea floor) where we can obtain the dating, associated materials and other information we would get if we were excavating on land.”
Neanderthals (Homo neanderthalensis) were our close evolutionary cousins; they appear in the fossil record some 400,000 years ago.
These resourceful, physically powerful hunter-gatherers dominated a wide range spanning Britain and Iberia in the west, Israel in the south and Siberia in the east.
Our own species, Homo sapiens, evolved in Africa, and replaced the Neanderthals after entering Europe about 40,000 years ago.
The specimen was found among animal remains and stone artefacts dredged up 15km off the coast of the Netherlands in 2001.
The fragment was spotted by Luc Anthonis, a private fossil collector from Belgium, in the sieving debris of a shell-dredging operation.
Study of the specimen has been led by Professor Jean-Jacques Hublin, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
“Even with this rather limited fragment of skull, it is possible to securely identify this as Neanderthal,” Professor Hublin told BBC News.
For instance, the thick bony ridge above the eyes – known as a supraorbital torus – is typical of the species, he said.
The fragment’s shape best matches the frontal bones of late Pleistocene examples of this human species, particularly the specimens known as La Chapelle-aux-Saints and La Ferrassie 1.
These examples, which were both unearthed in France, date from between 50,000 and 60,000 years ago.
The North Sea fossil also bears a lesion caused by a benign tumour – an epidermoid cyst – of a type very rare in humans today.
The research links up with the Ancient Human Occupation of Britain 2 (AHOB 2) project, which aims to set Britain’s prehistory in a European context. Dutch archaeologist Wil Roebroeks, a collaborator on this study, is a member of the AHOB 2 research team.
Dr Mike Richards, from the Max Planck Institute in Leipzig, analysed different forms, or isotopes, of the elements nitrogen and carbon in the fossilised bone. This shed light on the types of foods eaten by this young male.
The results show he was an extreme carnivore, surviving on a diet consisting largely of meat.
“High in the food chain, they must have been quite rare on the ground compared to other mammals, which explains their rarity to some degree,” said Wil Roebroeks from the University of Leiden.
The results of the stable isotope analysis fit with what is known about other examples of this species, though other research suggests that in Gibraltar, on the southern coast of Iberia, some Neanderthals were exploiting marine resources, including dolphins, monk seals and mussels.
Researchers decided against carbon dating the specimen; this requires the preservation of a protein called collagen.
Professor Hublin explained that while there was some collagen left in the bone, scientists would have needed to destroy approximately half of the fossil in order to obtain enough for dating.
Professor Roebroeks told BBC News: “Dutch scientists – geologists and archaeologists alike – are hoping this find will convince governmental agencies that the Netherlands needs to invest much more in that… archive of Pleistocene sediments off our coast – and off the coast of Britain.”
He said this submerged repository contained “high resolution information on past climate change and its environmental consequences, points of reference for how rivers ‘worked’ before any human interference and now, as this find shows, remains of people who once roamed these landscapes.”
Professor Hublin said the individual was living at the extreme edge of the Neanderthals’ northern range, where the relatively cold environment would have challenged their capabilities to the limit. Neanderthal remains have been found at only two sites this far north.
“What we have here is a marginal population, probably with low numbers of people,” Professor Hublin explained.
“It’s quite fascinating to see that these people were able to cope with the environment and be so successful in an ecological niche which was not the initial niche for humans.”
While these hunting grounds would at times have provided plentiful sources of meat for a top carnivore, Neanderthals living in these areas would also have been at the mercy of fluctuations in the numbers of big game animals.
Periodic dips in populations of mammals such as reindeer could have caused local extinctions of Neanderthal groups which hunted them, Dr Hublin explained.
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.
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- noemi su Scelidosauro esposto al museo di Bristol (Gran Bretagna)
- Andrea su 2009-02-02 – Bologna Mineral Show
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