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:
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
Proteins, soft tissue from 80-million-year-old dino support theory that molecules preserve over time
A North Carolina State University paleontologist has more evidence that soft tissues and original proteins can be preserved over time – even in fossilized remains – in the form of new protein sequence data from an 80 million-year-old hadrosaur, or duck-billed dinosaur.
Dr. Mary Schweitzer, associate professor of marine, earth and atmospheric sciences at NC State with a joint appointment at the N.C. Museum of Natural History, along with colleague Dr. John Asara from the Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School, Dr. Chris Organ from Harvard University, and a team of researchers from Montana State University, the Dana Farber Cancer Institute, and Matrix Science Ltd. analyzed the hadrosaur samples.
The researchers’ findings appear in the May 1 edition of Science.
Schweitzer and Asara had previously used multiple methods to analyze soft tissue recovered from a 68 million-year-old Tyrannosaurus Rex. Mass spectrometry conducted on extracts of T. rex bone supported their theory that the materials were original proteins from the dinosaur.
These papers were controversial, and the team wanted to demonstrate that molecular preservation of this sort in dinosaurs was not an isolated event. Based upon other studies, they made predictions of the type of environment most likely to favor this preservation, so Schweitzer and students, working with Jack Horner’s Museum of the Rockies field crews, went looking for a dinosaur preserved under a lot of sandstone. Using specially designed field methodology, with the aim of avoiding environmental exposure until the fossil was inside the lab, they set aside the femur from a Brachylophosaurus canadensis – a hadrosaurid dinosaur–buried deeply in sandstone in the Judith River formation.
“This particular sample was chosen for study because it met our criteria for burial conditions of rapid burial in deep sandstones,” Schweitzer says. “We know the moment the fossil is removed from chemical equilibrium, any organic remains immediately become susceptible to degradation. The more quickly we can get it from the ground to a test tube, the better chance we have of recovering original tissues and molecules.”
Preliminary results seemed to confirm their methodology, as Schweitzer found evidence of the same fibrous matrix, transparent, flexible vessels and preserved microstructures she had seen in the T. rex sample in the much older hadrosaur bone. Because of the rapidity of analyses after the bones were removed, the preservation of these dinosaurian components was even better. The samples were examined microscopically via both transmitted light and electron microscopes to confirm that they were consistent in appearance with collagen. They were also tested against antibodies that are known to react with collagen and other proteins.
Next, Schweitzer sent the samples to Asara’s lab to be analyzed by a new mass spectrometer, capable of producing sequences with much greater resolution than the one used previously. Mass spectrometry identifies molecules by measuring the mass of the protein fragments, or peptides, that result from breaking apart molecules with specific enzymes. The masses are measured with very high mass accuracy, and then compared with existing databases of proteins to achieve a best fit. In this way, Asara was able to identify eight collagen peptides from the hadrosaur, then confirm the identity of the sequences by comparing them both to synthesized fragments and to modern proteins analyzed under the same conditions. Once sequence data were validated, they were evaluated by Organ who determined that, like T.rex, this dinosaur’s protein family tree is closer to that of modern birds than that of alligators.
All results were independently verified by researchers at BIDMC, Montana State University, Harvard University, the Dana Farber Cancer Institute, and Matrix Science of London.
The data were consistent with that of the earlier T. rex analysis, confirming that molecular preservation in fossilized remains is not an isolated event. “We used improved methodology with better instrumentation, did more experiments and had the results verified by other independent labs,” Schweitzer says. “These data not only build upon what we got from the T. rex, they take the research even further.”
Schweitzer hopes that this finding will lead to more work by other scientists on these ancient molecules.
“I’m hoping in the future we can use this work as a jumping off point to look for other proteins that are more species-specific than collagen. It will give us much clearer insight into all sorts of evolutionary questions.”
Contact: Tracey Peake – firstname.lastname@example.org – 919-515-6142 – North Carolina State University###
An abstract of the paper follows.
“Biomolecular Characterization and Protein Sequences of the Campanian Hadrosaur Brachylophosaurus canadensis”
Authors: Mary H. Schweitzer, North Carolina State University and the N.C. Museum of Natural Sciences; John M. Asara, Beth Israel Deaconess Medical Center and Harvard Medical School, et al.
Published: May 1, 2009 in Science
Abstract: Molecular preservation in non-avian dinosaurs is controversial. We present multiple lines of evidence that endogenous proteinaceous material is preserved in bone fragments and soft tissues from an 80 million year old Campanian hadrosaur, Brachylophosaurus canadensis (MOR 2598). Microstructural and immunological data are consistent with preservation of multiple bone matrix and vessel proteins, and phylogenetic analyses of Brachylophosaur collagen sequenced by mass spectrometry robustly support the bird-dinosaur clade, consistent with an endogenous source for these collagen peptides. These data complement earlier results from Tyrannosaurus rex (MOR 1125) and confirm that molecular preservation in Cretaceous dinosaurs is not a unique event.
Un nuovo dinosauro con le piume
Il ritrovamento in Cina di un nuovo fossile di dinosauro dotato di piumaggio riapre il dibattito sulla diffusione di questi rettili preistorici. Questa volta gli scienziati hanno portato alla luce un piccolo esemplare che viveva nelle regioni nord-orientali del continente asiatico più di cento milioni di anni fa. L’animale aveva il corpo coperto da lunghi filamenti simili a piume, era piccolo, agile e scattante. Camminava su due zampe, aveva una lunga coda e si cibava probabilmente di piante, insetti e piccoli vertebrati.
PENNUTI PREISTORICI – È stato chiamato Tianyulong confuciusi, dalla somma del nome del museo dove è conservato e di quello del filosofo Confucio. Diversamente dai dinosauri «piumati» ritrovati fino ad oggi e appartenenti al sottordine dei teropodi (di cui fa parte anche il T-rex), questo pennuto preistorico è un eterodontosauride vissuto nel Cretaceo inferiore, circa 144 milioni di anni fa. Secondo gli scienziati le sue piume sono diverse sia da quelle degli uccelli che da quelle dei cugini teropodi: si tratta infatti di strutture meno flessibili e più compatte, e comunque non adatte al volo. Ma nonostante le differenze, sicuramente tutte le tipologie di proto-piume conosciute sono correlate tra loro.
L’ETÀ DELLE PIUME – Secondo alcuni paleontologi quindi le piume primitive sono una caratteristica ereditata dai due gruppi di dinosauri da un antenato comune e risalgono presumibilmente a 200 milioni di anni fa. Grazie alle particolari condizioni geologiche della provincia cinese del Liaoning, è sempre più frequente il ritrovamento di fossili di dinosauri provvisti di piume, e ciò fa pensare che fossero molto più diffusi di quanto si pensasse fino a pochi anni fa. Resta comunque ancora oscura la funzione (probabilmente ornamentale) di queste appendici che, come le piume degli uccelli attuali, erano molto colorate ma sicuramente alle origini non erano nate per volare
19 marzo 2009
Reconstruction of Tianyulong confuciusi, a feathered heterodontosaurid ornithischian dinosaur (Illustration: Li-Da Xing)
Approfondimento sui Blog
Earliest feathered dinosaur discovered
Primitive plumes probably used for display, scientists say.
A primitive form of feather may have evolved much earlier than was previously thought, according to an analysis of a dinosaur fossil that is more than 100 million years old. The specimen supports arguments that dinosaurs may have used feathers for display.
Finding feathers in dinosaurs is becoming a common occurrence. This is especially true in China’s Liaoning Province, where fine-grained sedimentary rocks often contain fossils with exquisite details still intact. But all of these feathered fossils have been of the bipedal, carnivorous theropod lineage, which includes Tyrannosaurus and Velociraptor.
Now, Xiao-Ting Zheng at the Shandong Tianyu Museum of Nature in China suggests that feathers were not limited to the theropods. He and his colleagues have discovered a dinosaur fossil in Liaoning that has long feather-like structures sticking up from its body. Based on the bones present, it looks like it was small, active, agile, and probably eating a mix of insects, small vertebrates and plants.
The team has identified the species as a heterodontosaurid from the Early Cretaceous period, which began about 144 million years ago. This in itself is remarkable as heterodontosaurids were most widespread during Late Triassic times, more than 65 million years earlier, and animal groups rarely survive for such long periods of geological time. “Heterodontosaurids are exceptionally rare, and previously unknown from Asia,” says Richard Butler at the Natural History Museum in London. This fossil “confirms that heterodontosaurids, one of the oldest groups of dinosaurs, survived into the Cretaceous”, Butler adds.
The skull of Tianyulong confuciusi. - X-T Zheng et al
Dinosaurs are divided into two main orders: saurischians, which have forward-pointing pubic bones, and ornithischians, which have backward-pointing pubic bones. All previous feathered theropods belong to the saurischian order, whereas the new fossil belongs to the ornithischian.
The find “pulls the origin of feathers down into the Triassic, when the saurischian and ornithischian lineages of dinosaurs split”, says Philip Currie at the University of Alberta in Canada. The fossil is described this week in Nature1.
Birds of a feather
The feathery structures found on this heterodontosaurid, dubbed Tianyulong confuciusi, are not like those found on modern birds or even on some of the smaller, more bird-like theropods. Whereas modern feathers are flexible and have a central shaft with vanes that run off either side at angles, the feathers on T. confuciusi are all relatively stiff and lack vanes.
To date, only one ornithischian fossil find has suggested the presence of anything that approximates feathers: Psittacosaurus has bristle-like structures on its tail that have been hotly debated. T. confuciusi will no doubt add fuel to the debate about whether feathers evolved once, twice or many times.
Hai-Lu You, one of the palaeontologists who identified T. confuciusi, believes that the fossil supports the idea of a single evolution of feathers. “We still have some missing data between T. confuciusi and feathered theropod dinosaurs, but I think further discovery will fill these gaps,” he says. If this proves to be true, then many dinosaurs may once have sported feather-like structures, with descendant species losing the characteristic later on.
At present, no-one is sure of the function of the protofeathers. “If these are protofeathers, then they were not related in any way to flight,” explains Butler. “The fact that the filaments over the tail are so long and stiff suggests a possible display function.”
“Dinosaurs were clearly highly visual animals that not only modified their skeletons for show, but exaggerated their effect through external structures,” adds Currie. “It doesn’t take that much to imagine dinosaurs as colourful as their descendants — the birds.”
San Francisco Chronicle – 12 ore fa
Fossil hunters in China have discovered a strange little dinosaur that lived more than 100 million years ago and had tough skin with patches of spiky …
Xiao-Ting Zheng, Hai-Lu You, Xing Xu & Zhi-Ming Dong
Nature 458, 333-336 (19 March 2009) | doi:10.1038/nature07856
Ornithischia is one of the two major groups of dinosaurs, with heterodontosauridae as one of its major clades. Heterodontosauridae is characterized by small, gracile bodies and a problematic phylogenetic position1, 2. Recent phylogenetic work indicates that it represents the most basal group of all well-known ornithischians3. Previous heterodontosaurid records are mainly from the Early Jurassic period (205–190 million years ago) of Africa1, 3. Here we report a new heterodontosaurid, Tianyulong confuciusi gen. et sp. nov., from the Early Cretaceous period (144–99 million years ago) of western Liaoning Province, China. Tianyulong extends the geographical distribution of heterodontosaurids to Asia and confirms the clade’s previously questionable temporal range extension into the Early Cretaceous period. More surprisingly, Tianyulong bears long, singular and unbranched filamentous integumentary (outer skin) structures. This represents the first confirmed report, to our knowledge, of filamentous integumentary structures in an ornithischian dinosaur.
Correspondence to: Hai-Lu You: Email: email@example.com).
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Researchers discover bones of armored dinosaur
College of Eastern Utah researchers have located the largest nodosaur ever, according to a December 2008 article in the Journal of Vertebrate Paleontology. The Nodosaur is an armored dinosaur that is part of the a group known as ankylosaurs.
The article written by Kenneth Carpenter of the Denver Museum of Nature and Science with the assistance of Jeff Bartlett, John Bird and Reese Barrick of the CEU Museum, reports that bones of a partial skull and post-cranial skeleton of a new large nodosaurid anklylosaur were found in the Cedar Mountain Formation southeast of Price.
Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), East-Central Utah
Kenneth Carpenter, Jeff Bartlett, John Bird, Reese Barrick – pg(s) 1089–1101
A new large nodosaurid ankylosaur, Peloroplites cedrimontanus, is described from a partial skull and postcranial skeleton found at the PR-2 Quarry located at the base of the Mussentuchit Member of the Cedar Mountain Formation in central Utah. The specimen is about the same size as the contemporary nodosaurid Sauropelta edwardsorum from the Cloverly Formation of Montana, and is of an individual approximately 5–5.5 m long. The skull of Peloroplites differs from that of Sauropelta in the vertical orientation of the suspensorium, non-domed cranium and broad, square premaxillary beak. The quarry is near and roughly at the same level as the CEM Quarry that produced the holotype of the ankylosaurid Cedarpelta bilbeyhallorum. The postcrania of Cedarpelta is described and illustrated based on the paratype and new material. These elements clearly establish that Cedarpelta is closer to Ankylosaurus than to Sauropelta. As a primitive ankylosaurid, there is no a priori reason to assume that the tail club was present. Based on recent finds in China, a hypothesis is presented that the tail club is a derived feature in non-shamosaurine (i.e., ankylosaurine) ankylosaurids.
Abstract & References : Full Text : PDF (2257 KB) : Rights & Permissions
In un nuovo articolo scientifico free access su PLOS descritte evidenze di combattimento per i Triceratopi
January 28, 2009 in Archaeology & Paleontology
Horning In on Triceratops
In a study published in the journal PLoS ONE, researchers conjecture that the three horns of Triceratops were often used for fighting–because museum specimens show much more scarring than in the horns of a related species. Cynthia Graber reports
Triceratops, as the name suggests, were huge dinosaurs adorned with three horns on their heads. Scientists now say those horns may have been a sort of battle bludgeon. Andrew Farke is a curator at the Raymond M. Alf Museum of Paleontology in California. He became curious about that headgear. Farke and colleagues wanted to investigate whether Triceratops fought each other with their horns. Which posed a problem: obviously, we can’t go back in time to watch the animals interact. So the researchers resorted to some techniques out of a Cretaceous CSI.
They examined more than 400 museums specimens of Triceratops and another closely related one-horned dinosaur called Centrosaurus. They scanned the skulls for injuries around where Triceratops might have locked horns and wrestled. Their assumption was that if the horns were just for display, both species would show few scars.
But the Triceratops had 10 times more skull injuries than their Centrosaurus cousins. The most likely explanation is that they probably jabbed each other in the head while fighting. The researchers published their findings in the journal Public Library of Science ONE. They also caution that the horns could have served more than one purpose—perhaps fighting and flaunting.
Triceratops benutzte Hörner als Waffen
Spiegel Online – 2 ore fa
Auch die These, die Dinosaurier hätten damit Fressfeinde wie den Tyrannosaurus rex abgewehrt, ist verbreitet – ebenso wie die Annahme, Triceratops habe die Hörner im Kampf gegen Artgenossen benutzt und mit dem Nackenschild gegnerische Stöße abgewehrt. …
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Uno studio presentato dai paleontologi Lawrence Witmer and Ryan Ridgely sulla base di tomografie computerizzate di due predatori, Tyrannosaurus rex e Majungasaurus, e due anchilosauri, Panoplosaurus e Euoplocephalus; ha consentito di ottenere uno schema più completo dei crani dei dinosauri e quindi anche di prsentare interessanti teorie sulla loro fisiologia.
Nello specifico lo studio mostra come i crani dei dinosauri presentano più vuoti del previsto avvalorando la nota considerazione secondo la quale essi permettevano di allegerire il peso della testa (“ruolo biomecanico”).
Inoltre, riguardo gli anchilosauri, le narici convolute favorivano il riscaldamento dell’aria inspirata
Dinosaurs Were Airheads, CT Scans Reveal
ScienceDaily (Dec. 9, 2008) — Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads.
Compared to brainy humans, dinosaurs were airheads. The head of Tyrannosaurus rex was filled with sinuses that lightened the head while enhancing its strength. (Credit: Art by Lawrence Witmer/Ryan Ridgely)
A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.
“I’ve been looking at sinuses for a long time, and indeed people would kid me about studying nothing—looking at the empty spaces in the skull. But what’s emerged is that these air spaces have certain properties and functions,” said Witmer, Chang Professor of Paleontology in Ohio University’s College of Osteopathic Medicine.
Witmer and Ridgely examined skulls from two predators, Tyrannosaurus rex and Majungasaurus, and two ankylosaurian dinosaurs, Panoplosaurus and Euoplocephalus, both plant eaters with armored bodies and short snouts. For comparison, the scientists also studied scans of crocodiles and ostriches, which are modern day relatives of dinosaurs, as well as humans.
The analysis of the predatory dinosaurs revealed large olfactory areas, an arching airway that went from the nostrils to the throat, and many sinuses—the same cavities that give us sinus headaches. Overall, the amount of air space was much greater than the brain cavity.
The CT scans also allowed Witmer and Ridgely to calculate the volume of the bone, air space, muscle and other soft tissues to make an accurate estimate of how much these heads weighed when the animals were alive. A fully fleshed-out T. rex head, for example, weighed more than 1,100 pounds.
“That’s more than the combined weight of the whole starting lineup of the Cleveland Cavaliers,” Witmer said.
Witmer suggests that the air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have been without all the air. That savings in weight could have allowed the predators to put on more bone-crushing muscle or even to take larger prey.
These sinus cavities also may have played a biomechanical role by making the bones hollow, similar to the hollow beams used in construction — both are incredibly strong but don’t weigh as much their solid counterparts. A light but strong skull enabled these predators to move their heads more quickly and helped them hold their large heads up on cantilevered necks, explained Witmer, who published the findings in a recent issue of The Anatomical Record.
Though most researchers have assumed that the nasal passages in armored dinosaurs would mimic the simple airways of the predators, Witmer and Ridgely found that these spaces actually were convoluted and complex. The passages were twisted and corkscrewed in the beasts’ snouts and didn’t funnel directly to the lungs or air pockets.
“Not only do these guys have nasal cavities like crazy straws, they also have highly vascular snouts. The nasal passages run right next to large blood vessels, and so there’s the potential for heat transfer. As the animal breathes in, the air passed over the moist surfaces and cooled the blood, and the blood simultaneously warmed the inspired air,” said Witmer, whose research is funded by the National Science Foundation. “These are the same kinds of physiological mechanisms we find all the time in warm-blooded animals today.”
These twisty nasal passages also acted as resonating chambers that affected how the ankylosaurs vocalized. The complex airways would have been somewhat different in each animal and might have given the dinosaurs subtle differences in their voices.
“It’s possible that these armored dinosaurs could recognize individuals based on the voice,” said Witmer, who noted that his research team’s studies of the inner ear revealed a hearing organ that probably had the capability to discriminate these subtle vocal nuances.
Though Witmer found few similarities between the dinosaur and human sinuses—our brain cavities take up much more space relative to our sinuses— the scientist did find a resemblance between the air spaces of the crocodiles and ostriches and the ancient beasts under study.
“Extra air space turns out to be a family characteristic,” he said, “but the sinuses may be performing different roles in different species. Scientists have tended to focus on things such as bones and muscle, and ignored these air spaces. If we’re going to decipher the mysteries of these extinct animals, maybe we need to figure out just why it is that these guys were such airheads.”
Hadrosaurus foulkii, the fossil phenom
The Academy of Natural Sciences will open its newest exhibit, “Hadrosaurus Foulkii: The Dinosaur That Changed the World,” at 10 a.m. Saturday.
The exhibit will commemorate the 150th anniversary of the scientific recognition of the Hadrosaurus foulkii, the most complete dinosaur skeleton found to that time.
Discovered in Haddonfield in 1858, the fully mounted skeleton of the 23-foot-long plant-eater will be displayed at the academy for the first time since the 1930s.
Three scenes will tell the story of Hadrosaurus foulkii. Visitors will learn about the discovery of the fossilized bones, the role of academy curator and University of Pennsylvania anatomy professor Joseph Leidy in identifying them, and the efforts of artist and naturalist Benjamin Hawkins to first capture what the dinosaur looked like.
Through April 19, the academy will host Hadrosaurus foulkii-themed events and attractions, including Dino Weekend beginning next Friday through Nov. 30, and Dinosaur Day on Dec. 27. Paleopalooza, Feb. 14 to 16, will feature presentations by scientists and fossil experts.
“Hadrosaurus Foulkii: The Dinosaur That Changed the World,” 10 a.m.-5 p.m. Saturday and Sunday (exhibit opens at 9 a.m. Saturday for members and will be on display until April 19) at the Academy of Natural Sciences, 1900 Benjamin Franklin Parkway. Admission: $10, $8 for children ages 3-12, seniors, college students, and military members, and free for academy members and children younger than 3. Information: 215-299-1000 or www.ansp.org.
La scoperta di un cranio di un giovane esemplare di Heterodontosaurus favorisce nuove considerazioni sulla dieta e sul percorso evolutivo di questo dinosauro.
Prima della scoperta, la presenza di una dentatura eteromorfa (e in particolare la presenza dei canini) aveva dato luogo a due considerazioni contrastanti; alcuni ritenevano che tale dentatura costituisse una prova di un alimentazione onnivora, altri invece che la presenza dei canini fosse propria soltanto dei maschi e rappresentasse quindi solo un carattere sessuale secondario (vedi l’esempio attuale dei Trichechi)
Ora la scoperta di un esemplare giovane con canini già ben sviluppati avvalora la tesi dell’onnivoria e pone il genere Hterodontosaurus coma una delle fasi di passaggio tra un antenato carnivoro e i successori ornitischi (triceratopi, adrosauri, anchilosauri) erbivori.
One of world’s smallest dinosaurs ever discovered ate meat AND plants
By Daily Mail Reporter
Last updated at 10:33 AM on 24th October 2008
[Photo: Laura Porro with her amazing find. The skull of a Heterodontosaurus had lain in a drawer since the 1960s]
One of the world’s smallest dinosaur skulls has been discovered, which could help explain how plant eaters branched off from their carnivorous cousins.
The tiny skull belongs to a young Heterodontosaurus, which lived 190million years ago, according to British and U.S researchers.
The mini dinosaur, which weighed around the same as an MP3 players, had fang-like canine teeth at the front for biting and tearing and flat grinding teeth typical of herbivores at the back.
‘Since Heterodontosaurs are among the earliest dinosaurs adapted to eating plants, they may represent a transition phase between meat-eating ancestors and more sophisticated, fully herbivorous descendants,’ Laura Porro from the University of Chicago said.
‘This juvenile skull indicates that these dinosaurs were still in the midst of that transition.’
Porro came across the skull in a drawer in the Iziko South African Museum in Cape Town, while researching the eating habits of the Heterodontosaurs. ‘
‘I didn’t recognise it as a dinosaur at first,’ she said.
‘But when I turned it over and saw the eye looking straight at me, I knew exactly what it was.’
Although dug up in the 1960s it was never identified. The dinosaur lived during the Early Jurassic period of South Africa. Porro’s find was reported in the Journal of Vertebrate Paleontology.
[Photo: The adult creatures were the size of turkeys but youngsters were half the size and only weighed half a pound, say researchers]
The first dinosaurs appeared about 230 million years ago, and the earliest known ones were meat eaters.
There were other plant-eating dinosaurs at the time of Heterodontosaurus including the long-necked sauropods. But this little creature was one of the earliest of the ornithischians that soon become very important in the Age of Dinosaurs.
Later ornithischians included the duck-billed dinosaurs, horned dinosaurs such as Triceratops and tank-like dinosaurs such as Ankylosaurus.
While adult Heterodontosaurus were turkey-sized creatures that reached just over three feet in length and weighed about five pounds (2.5 kg), the juvenile likely weighed less than half a pound and would have been just about a foot and a half long.
[Photo: The rare juvenile skull of a 190 million-year-old dinosaur may help explain when an important group of plant eaters branched off from their carnivorous cousins]
The find also offers a rare chance to compare a young dinosaur to adults in the species. Porro said the eyes in the juvenile skull are much bigger, and the nose is much shorter.
‘It’s the same things that makes puppies and kittens appealing,” she said. “I think it’s adorable.’
|Tiny dinosaur on verge of swearing off meat
Reuters UK – 10 ore fa
By Julie Steenhuysen CHICAGO (Reuters) – A rare juvenile skull of a 190 million-year-old dinosaur may help explain when an important group of plant eaters …
|Dinosaur ‘was turning vegetarian’
The Press Association – 10 ore fa
One of the smallest dinosaur skulls ever discovered belonged to a creature in the process of turning vegetarian, say scientists. …
Journal of Vertebrate Paleontology (the link will be inserted when available) (Bioone)
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.
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
istockAnalyst.com (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. …