Surfing The Wierd

Tuesday, April 8, 2008

Fossil Sea Monsters

http://news.nationalgeographic.com/news/2008/03/080326-ancient-reptile.html

PHOTO IN THE NEWS: New "Sea Monster" Species Identified

plesiosaur skeleton photo
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March 26, 2008—The remarkably well-preserved fossil of a dinosaur-era sea creature found in a Canadian mine is turning out to be a gold mine for paleontologists.

The Cretaceous-period reptile, dubbed Nichollsia borealis, is not only a new species—it represents a whole new genus, scientists announced on March 20.

It's also one of the oldest and most complete plesiosaur fossils ever unearthed in North America.

Plesiosaurs were carnivorous reptiles that roamed the seas between about 205 million to 65 million years ago.

Mine workers found the intact creature about 200 feet (60 meters) deep in a surface mine in Alberta in 1994. The Syncrude company extracts oil from the mine's sandy soil.

A "tomb" of sandstone preserved the 8.5-foot-long (2.6-meter-long) creature almost perfectly—unlike other plesiosaur fossils that are often found in porous shale.

The fossil ended up at the Royal Tyrrell Museum in Drumheller, Alberta, where University of Calgary paleontologists Patrick Druckenmiller and Anthony Russell recently ran 3-D CT scans of its braincase.

The scans and other analyses of the reptile have provided more detail than for any other plesiosaur ever found, they said.

The newfound reptile also gave them a window into an ancient seaway that once cut through North America and teemed with marine life.

(See pictures of a sea monster that lived in the Arctic.)

"This individual was a pioneer in the marine waters that would eventually become the Cretaceous Western Interior Seaway," Druckenmiller said in a statement.

"It represents the oldest known forerunner of this amazing period in North American prehistory."

Their research appeared in the German journal Palaeontographica Abteilung A.

N. borealis is now on display at the Discoveries Gallery at the Royal Tyrrell Museum.

—Christine Dell'Amore

Photograph courtesy Royal Tyrrell Museum, Drumheller, Alberta >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> http://news.nationalgeographic.com/news/2006/10/photogalleries/arctic-monster/

''Sea Monster'' Graveyard Found in the Arctic

''Sea monster'' photo
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A 33-foot-long (10-meter-long) marine reptile dubbed the Monster leaps from the water to snare a smaller reptile known as a plesiosaur in this artist's interpretation. The Monster is a member of a group of dino-era sea creatures called pliosaurs. Its fossil was among 28 specimens of predatory sea reptiles recently found on the Arctic island of Spitsbergen in Norway's Svalbard archipelago. The 150-million-year-old graveyard was unearthed by a team from the University of Oslo's Natural History Museum, along with a paleontologist from Montana State University in Bozeman. The remains of the Monster may represent the largest complete pliosaur ever found. So far the team has uncovered a skull measuring 6.9 feet (2.1 meters) in length, dinner plate-size neck vertebrae, and portions of the lower jaw with huge teeth that the scientists say are as thick as cucumbers.
Illustration by Tor Sponga, courtesy Natural History Museum, University of Oslo, Norway >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> http://news.nationalgeographic.com/news/2006/07/060711-dinosaur.html

Photo in the News: New Dino-Era Sea Predator Discovered

Dinosaur-era aquatic reptile, Umoonasaurus, illustration

July 11, 2006—Meet Umoonasaurus. About the size of a sea lion, the ancient marine reptile swam the shallow waters of an inland sea that covered Australia about 115 million years ago.

Distinguished by its relatively small size and three crestlike ridges on its skull, Umoonasaurus belonged to a group of ancient meat-eating marine animals known as plesiosaurs.

"The classic analogy for a plesiosaur is a snake threaded through the body of a turtle," said Benjamin Kear, a paleontologist at the University of Adelaide and the South Australian Museum.

"Imagine a sort of compact body with four flippers, a reasonably long neck, and a tail about half [as long] coming out the other end."

Kear and his colleagues identified the new species based on fossils of 30 individuals—including seven partial skeletons—found in old collections and recent excavations.

"The beauty of a lot of the Umoonasaurus material is that it comes out of opal mines," Kear said.

"You can imagine that these are quite spectacular-looking fossils, bright blue or green. You end up with this totally opalized skeleton."

The team named their archaic reptile swimmer after Umoona, the Aboriginal name for the South Australia region where the most complete Umoonasaurus skeleton was found—with a gut full of small fish.

A study describing the species appears in the latest online edition of the journal Biology Letters.

—Sean Markey

Illustration by Josh Lee/Adelaide/Biology Letters >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> http://news.nationalgeographic.com/news/2005/11/photogalleries/godzilla/

'Godzilla' Fossils Reveal Real-Life Sea Monster

monster leaping from ocean
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Fossils from a real-life sea monster—a massive crocodile-like species—have been unearthed in Patagonia, Argentina. The animal likely measured 13 feet (4 meters) long from nose to tail. The researchers who made the discovery say the marine reptile, nicknamed Godzilla, lived about 135 million years ago. They describe their find in the November 11, 2005, issue of the journal Science. Details about the ancient predator will also appear in the December 2005 issue of National Geographic magazine. The article will feature exclusive images, like this illustration, of what the reptile might have looked like.
Illustration © 2005 National Geographic >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> http://news.nationalgeographic.com/news/2005/10/1006_051006_plesiosaur.html
James Owen for National Geographic News
October 6, 2005

The fossilized last meals of two giant marine reptiles show the ancient animals used their long necks to trawl for clams, snails, and crabs along the seabed, according to a new study.

The discovery, based on the remains of two plesiosaurs unearthed in Queensland, Australia, challenges the long-held idea that these impressive ocean predators targeted only fish, squid, and other free-swimming prey.

Study co-author Alex Cook, assistant curator of fossils at the Queensland Museum, says the team was surprised by the fossilized sea creatures' last meals, eaten between 100 and 110 million years ago.

"Throughout the stomach region [of one specimen] were bits of broken clam and snail shell," Cook said. "There was also a fossilized food mass from the intestine, which was basically a solid lump of broken shell.

"This elasmosaur wasn't bothering much with fish—it was feeding almost entirely on bottom-dwelling mollusks."

The other elasmosaur's stomach contained crab and crustacean fragments.

Writing in tomorrow's issue of the journal Science, the Australian study team says the animals' varied diet could help explain why plesiosaurs were so successful. The predators prowled the Earth's oceans for some 135 million years before going extinct with the dinosaurs.

"Multipurpose Tool"

The two new specimens, each measuring 16 to 20 feet (5 to 6 meters) long and weighing around 2,200 pounds (1,000 kilograms), are from the elasmosaur family. These plesiosaurs had the longest necks of all—more than twice the length of their body and tail put together.

The bizarre-looking creatures became the inspiration for the Loch Ness Monster myth.

Colin McHenry, a biology lecturer at the University of Newcastle, New South Wales, describes the elasmosaur's extraordinary neck as a "multipurpose tool" for catching both free-swimming and seabed-burrowing prey.

"These were the dominant marine reptiles for 135 million years," he said. "The idea that the long neck was a generalized feeding tool is consistent with this success—specialized forms rarely last long.

Long-Necked Sea Reptiles Had Unexpected Diet, Fossils Show

"The almost impossibly long neck of an elasmosaur was one of the most successful structures in the history of life in the sea," he added.

The team's discovery provides hard evidence for a theory first suggested as long ago as the 1920s, according to plesiosaur expert Richard Forrest of the New Walk Museum in Leicester, England.

"Some plesiosaurs have rather long and slender teeth, which it has been suggested were for straining [the ocean floor] rather than biting," he said.

Forrest says "enigmatic traces" of such feeding behavior have been found in ancient seabed sediments in Switzerland.

"There are grooves in the sediments where it looks as if something has swept through it, and it's been suggested that this was done by plesiosaurs," Forrest said.

Yet in England, where numerous plesiosaur fossils have been unearthed, no evidence for bottom-feeding has been found.

Forrest says fossilized gut remains found in the region are "highly consistent with plesiosaurs living on things that swam past, such as fish, belemnites [squid-like carnivores], and even other plesiosaurs."

The paleontologist adds that around 60 percent of the plesiosaur bones found in Oxford Clay, a fossil-rich marine deposit in central England, have bite marks on them.

"Some of those are very obviously from the teeth of big plesiosaurs," he said.

Forrest suggests that differences in feeding habits might be because the two Australian elasmosaurs lived during the early Cretaceous period (144 to 127 million years ago), around 90 million years later than the English specimens.

"When you start coming to the Cretaceous you have mosasaurs taking the top marine predator role," he said.

Mosasaurs grew to a huge size and were armed with massive jaws and teeth.

Predator Competition

Forrest says competition from larger marine reptiles may have forced plesiosaurs to adopt different feeding strategies.

"The big plesiosaurs seem to have pretty well vanished by the [late] Cretaceous," he added. "Instead we have very big mosasaurs which had big, sharp, pointy teeth for crunching other animals."

The Australian finds may also help solve the riddle of why fossilized plesiosaurs are often found with large polished pebbles in their stomachs.

The function of the pebbles, called gastroliths, has been debated for years. The leading theory is that they were swallowed as ballast to help plesiosaurs hunt at deeper depths and to stop them from floating to the surface.

One of the two Queensland elasmosaurs contained 135 gastroliths.

Given the food remains found inside the two fossil skeletons, McHenry of the University of Newcastle thinks the main role of these stones is now obvious: Gastroliths would have been a useful digestive aid, helping the sea reptiles to crush up clams and crustaceans.

"An animal with stones in its stomach is going to make short work of a shellfish meal," he said.

"This doesn't necessarily sink the alternative theory—that they helped control buoyancy—but means that at the least gastroliths had a dual role," he added.

Angela Milner, associate keeper of paleontology at the Natural History Museum in London, says this idea makes sense.

"I don't think it has been suggested before that [gastroliths] might have acted as a gastric mill, but there is no real reason why not," she said.

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Plesiosaurs

Plesiosaurus hawkinsi: Cast of juveile animal, found in Somerset

Plesiosaur means 'near lizard'.

It was once thought that plesiosaurs were the descendents of the more primitive nothosaurs. However, some features of plesiosaurs are less derived than those of nothosaurs. It may be that plesiosaurs evolved from a more primitive diapsid, and not nothosaurs.

Plesiosaurs were larger than nothosaurs, and were more specialised for marine life. They appeared at the Triassic/Jurassic boundary (200 million years ago), and persisted until the end of the Cretaceous Period (65 million years ago).

Plesiosaurs are divided into 2 groups: 1. More primitive Plesiosauridae (short neck, large head). 2. More specialised elasmosaurs (long neck, small head).

Both groups swam with limbs that had evolved into paddles. Hyperphalangy (addition of joints to toes) increased the size of the paddles, and made them more efficient in swimming. Plesiosaurs used these paddles for propulsion instead of the tail.

In both groups, the nostrils were high on the head and just in front of the eyes. The genus Elasmosaurus is found in the upper Cretaceous, and its' lineage can be traced back to Plesiosaurus in the lower Jurassic.

The Elasmosaurus line is characterised by a progressive increase in the length of the neck, and a reduction in the size of the head. The size of the paddles relative to body size decreases from the Jurassic to the Cretaceous.

Elasmosaurs were not very streamlined, and this streamlining became poorer as the neck became longer. Elasmosaurs were consequently not fast swimmers. They were also not able to make swift movements of the head to capture prey, as the neck vertebrae were very stiff and inflexible. They may instead have pivoted the entire body, swinging the head rapidly through a large arc and enabling them to catch prey efficiently.

Elasmosaurus, an advanced Plesiosaur

Pliosaurs and early elasmosaurs both started with a body form that was very similar, but they followed different evolutionary pathways. The pliosaur pathway led to increasingly streamlined forms - the neck became shorter, and the paddles larger. Some pliosaurs reached very large sizes (e.g. Liopleurodon was 12-15m long), and ate fish, as well as smaller ichthyosaurs and plesiosaurs.

Liopleurodon, an advanced Pliosaur

Like nothosaurs, plesiosaurs probably had to return to land to lay eggs, despite their increased adaptation to aquatic life.

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