Scientist: Giant squid or octopus-like creature killed Nevada dinosaurs

A giant kraken is being fingered in the murder and odd arrangement of the remains of nine Nevada dinosaurs, the latest theory in a Silver State mystery that has perplexed scientists for over 50 years.

Mark McMenamin, a paleontologist at Mount Holyoke College, presented his theory Monday that a giant squid or octopus-like creature killed and arranged the remains of 45-foot icthyosaurs, a swimming dinosaur that is Nevada’s state fossil.

“It was either drowning them or breaking their necks,” McMenamin said of the kraken he believes killed the icthyosaurs. “Modern octopus will do this.”

McMenamin noted recent video of an octopus in an aquariuman attacking and killing an unsuspecting shark .

The icthyosaurs' fossils at Berlin-Ichthyosaur State Park in rural Nevada, appear arranged in a pattern that has intrigued and baffled scientists since the 1950s, according to a Geological Society of America news release.

The fossils are believed to be 220 million years old.

Other scientists have been skeptical of the kraken theory, arguing the extraordinary theory deserves extraordinary evidence.

The story has put the state in the science news, including the NPR treatment today on “Science Friday”.

The state's Department of Conservation and Natural Resources also issued a news release on the new theory.

Source: http://www.lasvegassun.com/news/2011/oct/14/scientist-giant-kraken-killed-nevada-dinosaur/

Alaskan Crater: Where Dinosaurs Once Roamed

Aniakchak National Monument and Preserve derives its name from a 6-mile (10-kilometer) caldera that sits midway down the Alaskan Peninsula. Geographers first noticed the circular feature on the landscape, and a 1922 geologic expedition confirmed the origin of the depression. Several decades later, paleontologists made another find at Aniakchak: Dinosaurs once lived in the area, and they left behind some of their fossilized tracks.

Aniakchak is one of 232 American parks with a stash of fossils. The National Park Service provides information on these natural relics as part of its celebration of National Fossil Day (October 12) and of Earth Science Week.

The Enhanced Thematic Mapper Plus on the Landsat 7 satellite captured this natural-color image of Aniakchak National Monument and Preserve on September 15, 2000. The caldera dominates the view, and the southern rim casts a blue-gray shadow on nearby snow and ice. (Because of the angle of sunlight, this image may cause the optical illusion known as relief inversion.)

A lake lies near the caldera’s northeastern margin. Vegetation is scarce immediately around the caldera, but farther away the slopes are green.

The caldera formed about 3,500 years ago when an explosive eruption blew out roughly 3,000 feet (1,000 meters) of overlying mountain. More recent volcanic activity has pockmarked the caldera with cinder cones and lava flows.

The dinosaur tracks in Aniakchak are far older than the crater. They were left by plant-eating dinosaurs about 70 million years ago. Anthony Fiorillo, based at the Museum of Nature and Science in Dallas, discovered the tracks and wrote about them in 2004. Left by hadrosaurs, the tracks consist of smaller handprints and larger footprints.

Most people think dinosaurs lived in tropical, or at least temperate, environments—not at high latitudes such as Alaska. So how could dinosaurs thrive so far north?

Plate tectonic theory indicates that some lands that are now situated at high latitudes once rested nearer to the equator. So one explanation could be that the landform wasn’t in the same place when the tracks were formed. However, studies of rock layers from the area indicate that the Aniakchak area was already in place at about the same latitude 70 million years ago.

Though Aniakchak was in roughly the same place (almost 57 degrees north), it doesn’t mean that it had the same climate. In fact, global climate about 70 million years ago was significantly warmer than today. So dinosaurs did not have to endure the temperatures common in modern Alaska, although they did experience some cold conditions and possibly snow. Regardless of temperatures, dinosaurs living at high latitudes coped with prolonged periods of darkness, as nighttime lasts nearly 18 hours during the winter in Aniakchak.

Source: http://www.ouramazingplanet.com/1913-alaskan-crater-where-dinosaurs-once-roamed.html

New Mexico’s Peculiar Two-Horned Dinosaur

On Sunday, I drove two and a half hours to meet a dinosaur. My journey was part of a trend this year. As I have traveled around the west, from Montana to New Mexico, I have sought out dinosaurs that I have never seen before, and while at this year’s National Association of Science Writers conference in Flagstaff, I found out that the Arizona Museum of Natural History in Mesa has a mount of a unique horned dinosaur called Zuniceratops. That was all I needed to know before getting on the southbound highway.

Though unfamiliar, Zuniceratops is not a brand new dinosaur. The creature was initially described by paleontologists Douglas Wolfe and Jim Kirkland in 1998, and even got a few minutes of relative fame in 2001′s When Dinosaurs Roamed America. Not too shabby for a relative newcomer, but what horned dinosaur can compete with the celebrity of Triceratops and ridiculously well-ornamented genera such as Styracosaurus? Zuniceratops was relatively small, had only two brow horns, and doesn’t look quite as imposing as its later Cretaceous relatives, but those characteristics are part of why this dinosaur is significant to paleontologists looking at the big picture of horned dinosaur evolution.

The bones of Zuniceratops were found in the roughly 89-million to 93-million-year-old rock of western New Mexico’s Zuni Basin. This makes the dinosaur one of the oldest known ceratopsians found in North America, and, as described by Wolfe and Kirkland, the remains of Zuniceratopsexhibit a mosaic of features shared with both earlier ceratopsians (such as Protoceratops) and the later, more familiar ceratopsids (such as Triceratops). While the body of Zuniceratops appeared to retain a more archaic, lightly built form, the prominent brow horns, the arrangement of the teeth (set up like a pair of scissors to shear vertically through food), a curved part of the hip called the ischium, and other characteristics underlined a close relationship to the ceratopsid dinosaurs that would eventually become so common on the continent.

But Zuniceratops was not a “missing link” or an ancestor to any of the ceratopsid dinosaurs. Instead, it is a peculiar dinosaur with a suite of features that may help us understand the transition between the more archaic ceratopsians and the early ceratopsids. The arrangement of anatomical characters in Zuniceratops gives us a general picture of what was happening among the horned dinosaurs at the time. After all, the grand pattern of evolution is a wildly branching tree of life, and in technical terms, Zuniceratops falls on a branch just outside the ceratopsid group—a relatively close cousin—but it did not share some of the telltale characteristics of the famous dinosaur group. Hopefully, as more dinosaurs like Zuniceratops are found, paleontologists will gain a clearer picture of how the greatest of the horned dinosaurs evolved.

Source:http://blogs.smithsonianmag.com/dinosaur/2011/10/new-mexicos-peculiar-two-horned-dinosaur/

Dinosaur teeth show Camarasaurus had seasonal migration

It wasn't just herds of bison that migrated across the vast plains of North America in the past. Giant sauropod dinosaurs such as Camarasaurus had seasonal migration too, according to scientists reporting in the journal Nature today.

Camarasaurus teeth from Dinosaur National Monument that were used in the study. Oxygen isotopes laid down in the tooth enamel give a record of what they drank and thus the landscape they occupied.

By studying fossil teeth from Camarasaurusspecimens, scientists led by Henry Fricke from Colorado College, USA, discovered these dinosaurs migrated long distances of up to 300km out of their usual habitat, and back again. This is the first evidence for dinosaur migration.

Around 150 million years ago in the Late Jurassic, Camarasaurus roamed the river floodplains of the Morrison basin in western North America. These huge herbivores, with their long necks and tails, were common in this area, despite the annual dry seasons when resources became scarce.

It has been a puzzle how populations ofCamarasaurus survived when they would have needed vast amounts of plants and water to eat and drink all year round.

This new research helps explain how - the animals moved out of their area seasonally. They may have migrated when there was drought, moving to places where food and water was more plentiful. But whether this was the incentive for the animals to move, or they did it instinctively whether resources were scarce or not, is not yet known.

Oxygen isotopes in teeth

The team studied the ratio of oxygen isotopes in Camarasaurus teeth. The oxygen comes from the surrounding soil, lakes and wetlands and the isotope ratios arespecific to a particular area.

The isotopes are laid down in the enamel as the tooth grows. The oldest enamel is at the tip, and youngest at the base. So, the isotopes recorded in the enamel becomes atimeline, like the growth rings of a tree, for example.

By comparing the oxygen isotope ratios in the tooth enamel with those in the animal's surroundings, scientists can tell where the animal was living at particular times.

The team found that at seasonal points, the isotope ratios in the Camarasaurus teeth differed from those in their home habitat. Instead, it corresponded to those from highlands 300km away.

This meant that Camarasaurus left their home and moved huge distances to higher, and probably more fertile, areas, the team says. However, the fact that their teeth are found in the basin means they returned to their homeland, maybe when conditions improved in the wet season.

Natural History Museum dinosaur and fossil expert (palaeontologist) Paul Barrettcomments on this research, ‘This work provides convincing evidence that at least some of the gigantic sauropod dinosaurs migrated considerable distances, probably in order to maintain a constant fuel supply to provide the energy for their enormous bodies.’

‘It builds on work that showed similar patterns for some other more recently extinct animals, such as mammoths, and raises the possibility of doing many more similar studies on dinosaurs and other long-extinct animals.’

Source:http://www.nhm.ac.uk/about-us/news/2011/october/dinosaur-teeth-show-camarasaurus-had-seasonal-migration105203.html

Montana’s “Dueling Dinosaurs”

In 1971, a team of Polish and Mongolian paleontologists discovered a spectacular pair of dinosaurs in the Cretaceous strata of the Gobi Desert. A Protoceratops and Velociraptor, the herbivore and carnivore were locked together in a lethal embrace and came to be known as the “Fighting Dinosaurs.” We will never know exactly what happened in the moments prior to their deaths, but the two appear to have been entombed as they tussled.

Now paleontologists in the United States are proposing that they have found a different example of a predator and potential prey in the same Cretaceous grave. In a series of YouTube videos, preparator Chris Morrow, self-described “Dino Cowboy” Clayton Phipps, Black Hills Institute paleontologist Peter Larson and Houston Museum of Natural Science curator Robert Bakker present the remains of two dinosaurs—a ceratopsid and a tyrannosaurid—found in the famous Hell Creek Formation. Both dinosaurs are being cleaned up and readied for study at CK Preparations in Fort Peck, Montana, where the videos were shot.

Exactly what the two dinosaurs are is unclear. The skull of the horned dinosaur looks very much like a large Triceratops, and the smaller tyrannosaurid looks like a juvenile Tyrannosaurus. But Larson and Bakker think otherwise. In one video, Larson points out a number of ambiguous features he suggests distinguish the horned dinosaur from Triceratops. In another video, Bakker describes features of the tyrannosaurid’s arm as vastly different from Tyrannosaurus. He and the others in the room identify the tyrannosaurid as Nanotyrannus, a controversial genus that Bakker named and Larson has supported. The specimens are spectacular in terms of their completeness and preservation, but whether or not they represent unknown or little-known genera of dinosaurs that lived alongside Triceratops and Tyrannosaurus is presently unclear. A solid understanding of dinosaur growth and variation will be needed to tell whether these dinosaurs are actually all that different from what has been found before.

So why are these two being called the “dueling dinosaurs”? At one point in the video, the assembled crowd wonders why the tyrannosaurid skull appears to be crushed. Clayton Phipps suggests that the predator was kicked in the head by the ceratopsid dinosaur right before both became buried. (Peter Larson supports this view in another video.) That may be, but we can’t use proximity alone to determine why these dinosaurs were found together.

The question is one of taphonomy: What happened between the deaths of the animals, their burial and their eventual discovery? Have paleontologists truly caught a tyrannosaurid in the act of trying to take down a ceratopsid, or is there some other explanation—such as a catastrophic local flood, or some sort of mire that trapped them—for why the two dinosaurs were found together? Think about the pose of the tyrannosaurid—the dinosaur is in the classic “death pose” with the head thrown back and tail arched up. Previous studies have indicated that this pose might be caused by death throes associated with a lack of oxygen reaching the brain, or, more simply, by immersion in water. If the tyrannosaurid had died after being kicked in the face by the ceratopsid, I would expect the body to be slumped over or otherwise in a different position. More research is needed. Speculating and coming up with hypotheses is fun, but a detailed understanding of geology and the prehistoric environment these animals died in is required to know whether we can truly call them “dueling dinosaurs.”

Still, the two dinosaurs look like they are fairly complete and well-preserved. Together they will almost certainly provide some new information about two of the most famous dinosaur lineages present in the Hell Creek Formation. We’ll just have to wait for the research to be completed before we can tell whether the more sensational elements of the story are true.

Source:http://blogs.smithsonianmag.com/dinosaur/2011/11/montanas-dueling-dinosaurs-2/

Scientists discover new dinosaur on Alaska's North Slope Read more: Fairbanks Daily News-Miner - Scientists discover new dinosaur on Alaska s North Slope

There’s a new kind of dinosaur out there, and it lived in Alaska.

Its bones, long turned to stone, are part of a cliff in northern Alaska. That’s where dinosaur-hunter Tony Fiorillo brushed dirt away from a portion of its massive skull, something that most of us would mistake for a rock.

The year was 2006. It was August and summer had fled the Colville River, if it had been there at all. Fiorillo, who visits Alaska each summer from Dallas, where he works at the Museum of Nature & Science, remembers climbing from his tent with a heavy head every morning. He later learned he was working with pneumonia.

On one wet, miserable day, Fiorillo was clinging to a hillside above the river, spading the soil gently with a trowel. Noticing an unusual lump, he picked up a brush to gently whisk the dirt away. Suddenly, an entire skull came into focus, and he felt a warm flush of discovery. “When I had that moment of recognition, only (a large nasal bone) was exposed,” Fiorillo said. “But in my mind I could see the rest of the skull.”

Fiorillo was excited because he could tell the specimen was one of the rare ones intact enough to be displayed in a museum, and the Museum of Nature & Science in Dallas was then planning a new building. As he and his digging partners, including Paul McCarthy of the Geophysical Institute and the University of Alaska Fairbanks Geology and Geophysics Department, unearthed the skull and coated it in plaster for a helicopter ride out, Fiorillo didn’t know they had found a species unknown to science.

The dinosaur, which lived in northern Alaska about 70 million years ago, is a plant eater with a massive shielded head that looked something like a Triceratops, only without a horn extending from its nose. Its mouth resembled a giant parrot’s beak.

“This animal had a face only a mother could love,” Fiorillo said.

Fiorillo and others have named the dinosaur Pachyrhinosaurus perotorum in honor of the family of former presidential candidate H. Ross Perot. In 2008, Perot’s children donated $50 million to the Dallas Museum of Nature & Science. 

The dinosaur is similar to two other thick-nosed species paleontologists have found, one in southern Canada and one in northern Alberta. But the Alaska version has subtle differences and is the youngest of the three by a few million years. 

Back when the horned plant-eater lived, the climate on Alaska’s North Slope fell somewhere between Portland, Oregon and Calgary, Alberta. The ground it stood upon was much closer to the north pole then, and creatures that lived there experienced great extremes of light and dark. Also living on the prehistoric coastal plain were three other plant eaters and four meat eaters, some with huge eyes for hunting during the dark season. Bones from all the dinosaurs are at the same rich site on a high bend of the Colville River.

Fiorillo and others didn’t know they had a new dinosaur for five years because it took that long to sort out all the dinosaur bones from a hunk of rock that flew by helicopter sling from the Colville River to a small airstrip, where a pilot flew it to Fairbanks. From there, it traveled down the Alaska Highway and all the way to Texas by truck. In Dallas, fossil preparer Ron Tykoski began the long task of chipping and carving apart the rock. He found the remains of many dinosaurs.

“It’s as if someone took 15 Pachyrhinosaurs, dumped them into a blender for 30 seconds, poured all the mess out into a ball of concrete, then let it solidify for 70 million years,” Tykoski said.

When he finished, the two paleontologists saw that several features on the skull were different enough from similar dinosaurs that no one had documented it until now. Fiorillo and Tykoski just unveiled the evidence for Pachyrhinosaurus perotorum at a paleontologist’s meeting in Las Vegas, reintroducing to the world an arctic dinosaur that once stomped through the ferns and forests of northern Alaska.

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute.

Source:http://newsminer.com/bookmark/16406692-Scientists-discover-new-dinosaur-on-Alaska-s-North-Slope

Dinosaurs hunted at night.

A new study has confirmed a belief held by some palaeontologists that some dinosaurs were active at night. Nocturnal animals need a maximum amount of light possible, so both their eyes and the eye openings tend to be larger than daytime animals. Researchers studied the fossilized eye sockets and scleroidal rings – a ring of bone that surrounds the iris of the eye in birds, lizards and dinosaurs. Of the 33 species studied most dinosaurs demonstrated some degree of nocturnal activity.

Most of the plant-eating dinosaurs were awake periodically. This means sporadically throughout the day or at dusk and dawn. All the predatory dinosaurs studied were either nocturnal or periodically hunting. Some Pterosaurs were also studied. They were mainly awake during the day, as was the case with all avian dinosaurs, although there was evidence of some species being nocturnal or awake periodically.

World smallest dinosaur.

What is thought to be the world’s smallest dinosaur has been discovered near Bexhill in East Sussex. The dinosaur, nicknamed ‘Ashdown maniraptoran’ after the brickworks where it was discovered, lived 145 to 100 million years ago during the early Cretaceous.

 It weighed only 200 grams and was no more than 30 cms long. ‘Ashdown’ was discovered by British palaeontologists. The skull has not been recovered so it is difficult to be definite about what the dinosaur ate. However based on other small maniraptorans it was probably an omnivore.

The closest rival to ‘Ashdown” for the record of ‘world’s smallest dinosaur’, is Anchiornis from China. It is believed to be between 30 to 40 cms long, but the uncertainty makes an exact comparison difficult.

Spinosaurus: new King Of Dinosaurs

T rex’s  long reign as king of the dinosaurs has now ended. Discoveries over the last few years have brought to light a few carnivorous dinosaurs that were even bigger. 

Spinosaurus is now the biggest land predator of all time at a massive 17 metres long. It had a long snout (about 99cm) with long, straight conical teeth that were perfectly adapted for its primary diet of fish. 

Spinosaurus would have hunted along the banks and shallows of the rivers and lagoons of what is now North Africa.

Vertebrae of sawfish have been found embedded in the fossilised remains of a Spinosaurus skull. We have a smaller cousin of Spinosaurus in Britain – Baryonyx. Spinosaurus lived in the middle of the Cretaceous period about 95 million years ago. The first fossils of Spinosaurus were discovered in 1912 in Egypt by Ernst Stromer and were taken back to Germany where they were subsequently destroyed in Allied bombing raids during World War II.

Spinosaurus is one of the stars of the BBC’s new Planet Dinosaur series – the long awaited follow up to Walking with Dinosaurs.

Administer Mind: Long doesn't mean big. Spinosaurus was long but he was lightly built and he was only 6 tons weight. He ate fish and he had jaws for hunting fish, not dinosaurus. I think he wasn't dangerous for example for Carhacodontosaurus who lived in same time and at same territory.

Source: http://www.thedinosaurmuseum.com/dinosaur-news/?p=204

New skeleton of Archaeopteryx

This year saw the 150th anniversary of the naming of Archaeopteryx – the iconic ‘missing link’ animal between dinosaurs and birds. Up until now only 10 specimens were known to exist, however now an 11th has been discovered and is ready for the scientists to study and name. 


The new specimen is very well preserved excepted that the skull and one forelimb are missing. The archaeopteryx is in the classic dinosaur death pose, and can be seen for the first time by the public at the Munich Show between 28th and 30th October.


Source:http://www.thedinosaurmuseum.com/dinosaur-news/?p=212

Facts

Dinosaur Facts The heaviest, the biggest, the smallest, the oldest... all the hottest dinosaur facts can be found here. The First Dinosaur to be Named The first dinosaur to be named was Megalosaurus. It was named in 1824 by Reverend William Buckland. Megalosaurus means ‘great lizard’ and it was about 9 metres long, and 3 metres tall. The First Dinosaur to be Discovered in America The first discovery of dinosaur remains in North America was made in 1854 by Ferdinand Vandiveer Hayden during his exploration of the upper Missouri River. He discovered a small collection of teeth which were later described by Joseph Leidy in 1856 as belonging to Trachodon, Troodon, and Deinodon. The Longest Dinosaur The longest dinosaur was Seismosaurus, which measured over 40 metres, as long as five double-decker buses. It was related to diplodocus, which for a long time held the honour.

More Dinosaur Facts The Heaviest Dinosaur The heaviest dinosaur was Brachiosaurus at 80 tonnes. It was the equivalent to 17 African Elephants. Brachiosaurus was 16m tall and 26m long and is the largest dinosaur skeleton to be mounted in a museum. The Smallest Dinosaur Egg - How To Tell a Dinosaur Egg from a Rock? Dinosaur eggs come in all shapes and sizes. They tend to be ovoid or spherical in shape and up to 30cm in length - about the size of a rugby ball. The smallest dinosaur egg so far found is only 3cm long. Once the egg has been fossilised it will become hard like rock, but it will retain a structure of its own. The Smallest Dinosaur The smallest fully-grown fossil dinosaur is the little bird-hipped plant-eater like lesothosaurus, which was only the size of a chicken. Smaller fossilised examples have been found, but these are of baby dinosaurs. The Most Brainy Dinosaur One of the most intelligent dinosaurs was Troodon. It was a hunting dinosaur, about 2 metres long, and had a brain size similar to that of a mammal or bird of today, stereoscopic vision, and grasping hands The Dumbest Dinosaur Stegosaurus had a brain the size of a walnut - only 3 centimetres long and weighing 75 grams. However, comparing brain size to body size sauropodomorphs, like Plateosaurus, were probably one of the dumbest dinosaurs. NEW Dinosaur Fact! The Tallest Dinosaur The tallest dinosaurs were the Brachiosaurid group of sauropods. Their front legs were longer than the rear legs giving them a giraffe-like stance. This combined with their extremely long necks, which were held vertically, meant they could browse off the tallest trees. Brachiosaurus - the most well known of the group - was 13 metres tall. Sauroposeidon was massive and probably grew to 18.5 metres tall making it the tallest dinosaur. The Fastest Running Dinosaur The speediest dinosaurs were the ostrich mimic ornithomimids, such as Dromiceiomimus, which could probably run at speeds of up to 60 kilometres per hour. The Oldest Dinosaur The oldest dinosaurs known are 230 million years old, and have been found in Madagasgar. As yet they have not been formally named. Before this Eoraptor, meaning "dawn thief" had held the title at 228 million years. The Longest Dinosaur Name The dinosaur with the longest name was Micropachycephalosaurus meaning "tiny thick-headed lizard". Its fossils have been found in China, and it was named in 1978 by the Chinese palaeontologist Dong. The Fiercest Dinosaur Tyrannosaurus rex looked the most ferocious of all the dinosaurs, but in terms of overall cunning, determination and its array of vicious weapons it was Utahraptor that was probably the fiercest of all. Utahraptor measured about 7 metres, and was a very powerful, agile and intelligent predator. The Largest Pterosaur Quetzalocoatlus with its wingspan of up to 13 metres was probably the largest pterosaur, and hence the largest flying creature of all time. Despite its size it weighed no more than 100 kilograms. Its only contender may be Arambourgiania, which is only known from one bone but scaled up the whole pterosaur could have been even larger. Pterosaurs were not dinosaur. The Largest Plesiosaur Elasmosaurus was the longest plesiosaur at up to 14 metres (46 ft) long. Half of its length was its neck, which had as many as 75 vertebrae in it (in comparison to 7-8 neck vertebrae in humans). Elasmosaurus had four long, paddle-like flippers, a tiny head, sharp teeth in strong jaws, and a pointed tail. Plesiosaurs were not dinosaurs but were marine reptiles. What killed the dinosaurs? It is believed that dinosaur extinction was part of a mass extinction brought about by two massive destructive events. The first of these was the collision with the Earth of a meteorite landing in what is now the Yucatan Peninsula, of Mexico. This was followed by an enormous volcanic eruption which split what is now India in half. How many types of dinosaur were there? At present over 700 different species of dinosaurs have been identified and named. However palaeontologists believe that there are many more new and different dinosaur species still to be discovered. How many species of dinosaurs have been found in Britain? So far 108 species of dinosaurs have been discovered in Britain. Britain was an important area during much of the Mesozoic Era acting as a 'land bridge' between North America and Eurasia. It became a hotspot for dinosaur evolution and migration. British dinosaurs include Megalosaurus, Iguanodon, Neovenator, Eotyrannus, and Cetiosaurus. The dinosaur Museum has the skeleton of a Megalosaurus and the skull of an Iguanodon on display. NEW Dinosaur Fact! Which is Britain's Oldest Dinosaur? The oldest known dinosaur so far discovered in Britain is Thecodontosaurus antiquus. It was discovered near Bristol in 1970 but only now has funding been achieved to excavate the dinosaur. Thecondontosaurus was 2.1 metres long, about the size of a kangaroo, and ate plants. It lived on the richly vegetated islands that were around that area in Triassic times about 200 million years ago.

Sea Monster Battle Seen in Prehistoric Bite Marks

An artist's rendition of a Mixosaurus, a genus of ichthyosaur, swimming.

A scarred fossil skull recovered in Australia is yielding a rare glimpse into the behaviors of dinosaur-era, battle-ready sea beasts.

The skull of the nearly 20-foot-long (6-meter-long) predator bears deep gouges and scratches on its slender snout.

"It was a really aggressive encounter" and featured a marine battle tactic not unfamiliar today, said paleontologist Benjamin Kear. "Modern marine animals tend to concentrate bites on the face, where all the dangerous hardware is at," said Kear, of Sweden's Uppsala University, who studied the ichthyosaur fossil with student Maria Zammit.

The attack, though, wasn't entirely successful for the aggressor—the wounds show signs of healing.

Swarming With Sea Monsters

Ichthyosaurs were dolphin-like reptiles that lived some 120 million years ago, during the Cretaceous period . Their toothy, three-foot-long (meter-long) snouts were equipped with roughly a hundred teeth to nab fish and squid in chilly southern oceans.

"Most of what you'd recognize in the oceans today were there, including sharks, shellfish, squid, starfish, and so on," Kear said. "Just take out whales and seals and replace them with ichthyosaurs, giant crocodile things with flippers, weird Loch Ness creatures, and other monsters."

One of those "giant crocodile things" was Kronosaurus, which grew to more than 40 feet (12 meters) long, had a head the size of a small car, and boasted teeth as big as bananas.

But while Kronosaurus may have eaten ichthyosaurs, the narrow bite pattern on the study fossil suggests the assailant was actually another ichthyosaur—a telling detail.

"Ichthyosaurs have no living relatives, so we have almost nothing to go on how they behaved or lived," Kear said. "These bite marks are priceless droplets of information, and they suggest ichthyosaurs have fought over carcasses, territory, or even each other."

Such insights were far from reach until recently. Though Australian miners digging a pipeline found the first fossil piece in the 1970s, the skull wasn't completed until after an Aborigine had stumbled upon the other bits in 2001.

Now that the skull and the bite study are complete, Kear and Zammit plan to probe the fossils for insights into how ichthyosaurs swam through the shallow inland oceans of the southern supercontintent Gondwana, which would eventually split into Africa, South America, Antarctica, and Australia.
Source:http://news.nationalgeographic.com/news/2011/05/110505-ichthyosaur-sea-monsters-battle-science-acta-bite-dinosaurs/

Pictures: Largest "Sea Monster" Skull Revealed?

Sea Monster's Big Bite

Photograph courtesy Jurassic Coast Team, Dorset County Council

Packing what may be the world's biggest bite, a recently revealed "sea monster" would have given Jaws a run for its money.

Put on display July 8 at the U.K.'s Dorset County Museum, the 7.9-foot-long (2.4 meter-long) skull (pictured) belonged to a pliosaur, a type of plesiosaur that had a short neck, a huge, crocodile-like head, and razor-sharp teeth. When alive about 155 million years ago, the seagoing creature would have had a strong enough bite to snap a car in half, according to the museum.

Amateur collector Kevan Sheehan found the skull in pieces between 2003 and 2008 at the Jurassic Coast World Heritage Site, a 95-mile (152-kilometer) stretch of fossil-rich coastline in England. The Dorset County Council's museums service purchased the fossil, and later research by University of Southampton scientists suggests that it's the largest complete pliosaur skull ever found. (Explore a National Geographic magazine sea monsters interactive.)

Yet Hans Sues, a paleontologist at the National Museum of Natural History in Washington, D.C., cautioned in an email that it's too early to say if the skull is indeed the largest.

"Some pliosaurs are gigantic animals, and there is an unfortunate tendency to brand every new find as the largest," said Sues, who is also a contributor to the National Geographic News Watch blog. (The National Geographic Society owns National Geographic News.)

"However, no evidence is ever presented to support these claims, which make for good media coverage but are scientifically unwarranted."

—Christine Dell'Amore

Source:http://news.nationalgeographic.com/news/2011/07/pictures/110712-pliosaur-fossil-sea-monster-biggest-skull/

"Sea Monster" Fetus Found—Proof Plesiosaurs Had Live Young?

A Polycotylus latippinus plesiosaur gives birth some 80 million years ago in an artist's conception.

Like whales, humans, and most other mammals, plesiosaurs—giant, long-necked marine reptiles of dinosaur times—gave birth to live young, a new fossil study suggests.

Even as it apparently solves one mystery, though, the finding raises another: Did the "sea monsters" swim in mother-child pairs or even in larger groups, like modern whales and dolphins?

The study focused on a 78-million-year-old, 15.4-foot-long (4.7-meter-long) adultPolycotylus latippinus plesiosaur fossil found in 1987. The fossil's abdominal cavity contains tiny bones—parts of a plesiosaur that hadn't been born by the time its mother died.

The finding, detailed in this week's issue of the journal Science, is the first proof that plesiosaurs were viviparous—that they gave birth to live young.

"The fetus is too large to make an egg physiologically or mechanically feasible," study co-author Robin O'Keefe told National Geographic News. "And why carry a big egg around?"

The discovery, while not completely unexpected, may fill a frustrating gap in plesiosaur knowledge, he said.

"Scientists have long known that the bodies of plesiosaurs were not well suited to climbing onto land and laying eggs in a nest [like dinosaurs]. So the lack of evidence of live birth in plesiosaurs has been puzzling," O'Keefe, a plesiosaur expert at West Virginia's Marshall University, said in a statement.

Mothering Monsters?

Live birth has been documented in other groups of ancient marine reptiles—such as the dolphin-like ichthyosaurs—but the study suggests plesiosaurs were unique, in that they generally gave birth to a single, large offspring, according to the study.

"Ichthyosaurs gave birth to multiple [small] progeny. That's what makes plesiosaurs stand out from other ancient marine reptiles," said study co-author Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles.

It's "certainly possible" that plesiosurs sometimes gave birth to twins or triplets, co-author O'Keefe said. "In fact, I would almost expect it."

Chiappe and O'Keefe estimate the unborn baby plesiosaur was nearly 5 feet (1.5 meters) long, or about a third the length of the mother.

Many of the animals living today that give birth to single, large babies are social and invest a lot of time and energy into raising their young. Plesiosaurs may have exhibited similar behavior, Chiappe said, making their parenting styles more like that of modern whales and dolphins than of most reptiles.

"The mother is essentially taking a risk, because if you want to have your genes propagated, you're putting a lot of energy into that single baby, so it's conceivable that the mother's investment of energy extended to after the baby was born," said Chiappe, who, like O'Keefe, has received funding for past projects from the Committee for Research and Exploration of the National Geographic Society (which owns National Geographic News).

Pick a Pack or Pod of Plesiosaurs?

Chiappe admits the active-parenting hypothesis could be difficult to test. But if baby plesiosaur fossils are repeatedly found alongside adults, it would support the idea of maternal care among the creatures, he said.

In such a case, maternal care "would be a more reasonable interpretation than saying" large and small plesiosaurs "died apart and somehow kept being buried together every time," Chiappe said.

The new discovery also raises the interesting question of what to call a group of plesiosaurs: a school? a pack? a pod?

"I haven't thought about that," Chiappe said. "I guess, colloquially, you could call them a pod"—a term generally reserved for marine mammals. "But from a scientific point of view, we would probably still use the term 'group.'"

Source:http://news.nationalgeographic.com/news/2011/08/110811-plesiosaurs-live-birth-fossils-young-science-chiappe-dinosaurs-fetus/

Giant Prehistoric Croc Found Near World's Biggest Snake

The new prehistoric croc species pursues prey while a Titanoboa snake lurks above (artist's conception).

A Colombian coal mine where scientists found the largest known snake species has offered up another gem: A new species of 20-foot-long (6-meter-long) prehistoric croc.

The 60-million-year-old Acherontisuchus guajiraensis lived alongside the snake and a bevy of other reptiles in an Amazon-like river system, which wove through one of Earth's earliest rain forests before eventually emptying into what's now the Caribbean Sea.

Within this wide, flat river, A. guajiraensis would've used its long snout to capture fish—also the favorite prey of Titanoboa. That meant the two heavyweights likely duked it out over food, with young crocs sometimes becoming dinner for the snake, experts say.

In fact, one of the problems a growing croc "would have had to deal with is trying to get fish without irritating Titanoboa to the point where, rather than going for the fish, it'd go for a croc," quipped study leader Alex Hastings, a University of Florida graduate student in vertebrate paleontology who works with the school's Florida Museum of Natural History.

Fossils Shed Light on Croc Evolution

Fossils of the prehistoric croc were first collected in 1994 by a geologist at the Cerrejón mine—one of the world's largest open-pit coal mines—and stored in the mine's offices until 2004.

Field expeditions between 2004 and 2007 uncovered more remains from the site, allowing researchers to piece together an adult specimen, according to the study, published recently in the journal Palaeontology.

Analysis of the fossils revealed that A. guajiranesis belonged to a family called the dyrosaurids, crocodilyforms that inhabited coastal and marine habitats. A crocodilyform is a reptile that belongs to the order Crocodilia, which includes crocodiles, alligators, caimans, and gavials, among other species.

The newfound species may give scientists several insights into the evolution and eventual fate of the dyrosaurids, whose history is still somewhat fuzzy, noted Christopher Brochu, a paleontologist at the University of Iowa.

For instance, it's known that the hardy creatures arrived in South America about 75 million years ago by literally swimming across the Atlantic Ocean from Africa. Dyrosaurids are also one of the few groups of big animals that survived the mass extinction that largely killed off the dinosaurs about 65.5 million years ago. The family later flourished into many sizes and shapes, said Brochu, who wasn't involved in the research

Yet environmental factors such as climate may have finally done them in, Brochu said. According to the fossil record, dyrosaurids dwindled as Earth grew chillier during the Eocene period (56 million to 49 million years ago).

"Getting a better understanding of the diversity and relationships of these animals enhances our ability to use these fossils to explore environmental change over time," he said.

New Croc Retreated to Rivers to Survive Mass Extinction

A. guajiranesis's discovery may lay to rest a theory that only young dyrosaurids spent time inland, before eventually returning to the sea to continue their life cycles.

Two features of the new species strengthen the idea that A. guajiranesis crocs spent their whole lives in rivers: The sheer size of the adult specimen, and the animal's long, slender pelvis, study leader Hastings said. Such a bone structure suggests the reptile had adapted over time to placid waters that did not require the bigger, flaring pelvis characteristic of marine crocodyliforms, which would've dealt with strong ocean currents.

Hastings also suspects A. guajiranesis initially retreated to rivers as a strategy to survive the extinction that killed off most life on Earth.

"It's neat it's able to inhabit this new territory and do well," Hastings said, "despite the fact there's a 42-foot [13-meter] snake hanging around."

Source:http://news.nationalgeographic.com/news/2011/09/110916-prehistoric-crocodile-new-species-largest-snake-titanoboa-science/

New Raptor Dinosaur Used Giant Claw to Pin, Slash Prey?

Artist's reconstruction of Talos sampsoni, a new raptor dinosaur unearthed in Utah.

Talk about a lucky break—paleontologists have found "incredibly rare" fossils of a new species of raptor dinosaur that severely fractured its giant-clawed foot about 76 million years ago, paleontologists say.





The six-foot-long (two-meter-long) Talos sampsonsi lived in the rainy, "hothouse world" of late-Cretaceous North America, which was then two continents—Laramidia in the west and Appalachia in the east—divided by a shallow seaway.


It's one of the few troodontid theropods—small, birdlike predators—ever discovered in North America, said study leader Lindsay Zanno, a vertebrate paleontologist at the Field Museum of Natural History in Chicago.


Doctoral student Mike Knell, who found Talos while searching for fossil turtles in Utah in 2008, "stumbled across one of the nicest raptors that we've found in North America," she said.


"It was a thrilling discovery for those of us who got to work on it."


The dinosaur is named for the mythological Greek figure Talos—a winged figure that supposedly could run at lightning speed—as well as Utah paleontologist Scott Sampson.


Raptor Dinosaur Used Talon to Puncture Prey?


Perhaps most exciting about Talos is its injured second toe, which has added to an existing debate on what troodontids did with the giant, sickle-like claw on that toe, study leader Zanno said.


Paleontologists have offered opposing explanations for the claw, for example that it helped troodontids climb, acted as a weapon in killing prey or fighting foes, or even enabled the dinosaur to clean itself.


When the scientists analyzed Talos's injured toe bone via a CT scanner, they found a mark that indicated that the injury—possibly caused by a bite from another animal—had been traumatic.


Assuming the dinosaur used the talon when walking, such a serious injury would've caused Talos to limp on that leg, which in turn would've caused obvious changes to the skeleton's structure, Zanno noted.


Instead, "we found the complete opposite," she said—the skeleton was otherwise unscathed.


This strengthens the theory that the raptor dinosaur carried its giant toe off the ground—an idea already supported by raptor tracks that lack claw marks, according to the study, published September 19 in the journal PLoS ONE.


Instead, Talos may have wielded its claw like a puncturing device when hunting, for example by getting a foothold as the raptor scrambled up a larger animal's back, Zanno said. Or, like some modern-day birds, the dinosaur may have used the claw as a weapon while fighting with other dinosaur rivals. (Take a dinosaur quiz.)


It's "giving us a window into the biology of the animal that we don't get from your average, everyday specimen," Zanno said.


(Also see "New Dinosaur Had Potbelly, Claws Like Wolverine.")


New Dinosaur an Omnivore?


The fact that the toe was traumatically injured at all suggests the dinosaur used it as a weapon, said Thomas R. Holtz, Jr., a vertebrate paleontologist at the University of Maryland, College Park.


Talos was "probably not going to get a wound like that from preening its feathers," said Holtz, who wasn't part of the study.


Based on the new findings and previous dinosaur tracks, Holtz suspects the dinosaur used its claw to pin down small animals and slash bigger prey.


What's more, the specimen's post-wound survival hints that the raptor was omnivorous, Holtz speculated. With its claw unusable for hunting, the dinosaur presumably had to eat plants or other foods to stay alive while it healed.


Holtz and colleagues have previously found that troodontids had teeth more like those of plant-eating reptiles than carnivorous ones, he added.


Study leader Zanno added, "In the end we can never observe the behavior of this animal—it's always going to be controversial."


But "the more individual lines of evidence that we can add that can support the [weapon] hypothesis, the stronger it becomes."


Source: http://news.nationalgeographic.com/news/2011/09/110921-new-raptor-dinosaur-fossils-talon-toe-killing-utah-science/

Best Evidence Yet for Dinosaur Migrations—Teeth Tell Tale

A Camarasaurus dinosaur (illustrated above) could grow longer than a school bus.

Sauropod dinosaurs may well have been the largest animals to ever walk—and walk and walk and walk—the Earth.



A new fossil-teeth analysis has uncovered the best evidence yet that dinosaurs migrated seasonally like modern-day birds or elephants, according to a new study.


Chemical signals in prehistoric tooth enamel reveal that roughly bus-lengthCamarasaurus dinosaurs walked hundreds of miles on marathon migrations in late Jurassic North America.

Responding to shifts in food and water availability, the long-necked plant-eaters likely trudged from floodplain lowlands to distant uplands and back again as the seasons changed across parts of what are now Utah and Wyoming, researchers say.

"On the African Serengeti the large mammals do a wet season-dry season migration and that's sort of what we're envisioning here," said Colorado College geochemist Henry Fricke, who led the study, published today in the journal Nature.

Fricke and colleagues theorize that the dinosaurs left a basin floodplain area at the onset of the summer dry season, when droughts may have been common and plant supplies limited.

The sauropods moved nearly 200 miles (300 kilometers) to highlands that were presumably cooler and wetter in that season, Fricke said. That's tough to prove, though, because erosion of the areas' ancient rock has deprived scientists of crucial evidence needed to "reconstruct" the long-gone highlands, he said.

The animals likely returned to the lowlands during the wet winters, when food and drink were again plentiful, he added.


The Telltale Teeth

Scientists have long suggested that some dinosaurs might have migrated, but it's been extremely hard to find any evidence for the behavior.

Fricke and colleagues compared ratios of oxygen isotopes—varying versions of the element—in the fossil Camarasaurus teeth with oxygen isotopes found in prehistoric layers of lowland soil.


Because the dinosaurs' teeth were replaced roughly every five months, each tooth offers a unique record of what the animal drank during the tooth's life span.

The soil and teeth turned out to have distinctly different oxygen-isotope ratios, suggesting the teeth had formed elsewhere, for the most part. The ratios in the teeth, tellingly, were akin to what you'd expect had the teeth grown at high elevations.

"We concluded that the sauropod had to be leaving the basin areas and going somewhere else," Fricke said.

And they may not have been alone. Fricke wonders whether the huge plant-eaters were followed in their migrations by predators like Allosaurus (picture),like wagon trains trailed by fleeter-footed marauders—the subject of a future study, he said.

Source: http://news.nationalgeographic.com/news/2011/10/111027-dinosaurs-migrated-nature-science-sauropods/