Ancient ''Sea Warrior'' Crocodile Unveiled National Geographic - March 27, 2008
Ancient ''Sea Warrior'' Crocodile Unveiled National Geographic - March 27, 2008
Fossil Crocodile From Brazil May Be "Missing Link" National Geographic - February 2, 2008
News in Science - June 14, 2006
A new fossil from the Age of the Dinosaurs suggests modern crocodiles first evolved in Gondwana, says an international team of palaeontologists. The team reports on the fossilized remains of the most primitive ancestor of modern crocodiles, discovered near an outback Australian town in Queensland.
"Up until now, the kinds of creatures that seemed to be the ancestors, or close to the ancestors, of all modern crocodiles have come from places like Belgium, from England, from the USA," says team member Dr Paul Willis. "So that's where we thought the group originated. But the new specimen, Isisfordia duncani, shares more features in common with modern crocodiles than any specimens found in the northern hemisphere. It really defines that branch of crocodile evolution more clearly than anything else we've come across to date. At 98 to 95 million years old, Isisfordia predates modern crocodiles by about 20 million years. Ours is the grand-daddy of crocodiles.
"Modern crocodiles are defined by having ball and socket joints between their vertebrae. This gives them a very flexible yet strong backbone. Crocodiles have incredible bursts of very violent energy and so you need a strong backbone to be able to withstand that.
"Modern crocodiles also have a hard palate that reaches right to the back of the mouth, which means they can breathe at the same time as eating something under wate. The palate also strengthens the snout, bracing it and distributing forces when the crocodile bites something. Crocodile bites are second only to Tyrannosaurus as the most powerful known bites of all time. All these features would have given Isisfordia and its descendants greater evolutionary advantage than its predecessors in aquatic environments."
Willis and colleagues analysed two fossilised skeletons first discovered in the mid-1990s in a creek bed in Isisford, in central-western Queensland, by former deputy mayor of the town, Ian Duncan. One specimen is almost a complete skeleton with just the snout and face of the crocodile missing. The other is a complete skull.
"Between the two we have a complete skeleton. We know what the whole animal looked like and it's very rare to get that. The researchers know the two are from the same species because they have the back of the skull of both.A small crocIsisfordia was a small crocodile, only a metre long, weighing around 3 or 4 kilograms. It was the only known crocodile in Australia at that time and wouldn't have had much competition. It would have lived in a swampy river delta that opened into a large inland sea and survived on eating, among other things, fish and other small vertebrates, insects and crustaceans.
"Isisfordia would have been the most immediate ancestor of all modern crocodilians. This includes crocodiles, alligators and creatures such as gharials (long thin-snouted crocodiles that live in the Ganges River) and caimans (close relatives of alligators from South America). This is not the first time that Gondwana has been overlooked as a site of evolution. The fossil record is loaded to the northern hemisphere because there are more sites and more people looking for fossils. But as we're finding more fossils in the Gondwanan continents it appears that a lot of groups that we previously thought originated in the northern hemisphere - or in Laurasia - actually have older representatives here in the southern continents, and in this case in Australia."
MSNBC - June 9, 2005
Scientists on Wednesday unveiled 11 skeletons of prehistoric crocodiles and said their discovery suggests that an ancient land bridge once linked South America to Indo-Pakistan.
The fossilized skeletons of the Baurusuchus salgadoensis appear to be closely related to another ancient crocodile species, the Pabwehshi pakistanesis discovered in Pakistan, scientists from Rio de Janeiro's Federal University said.
"This discovery really proves that South America was at one time linked to the India-Pakistan bloc, and this link could have only been through Antarctica or Australia," said Rudolph Trouw, regional editor of the scientific magazine Gondwana Research.90 million years old.
The Baurusuchus salgadoensis lived 90 million years ago in an area of southeastern Brazil known as the Bauru Basin, 450 miles (700) west of modern-day Rio de Janeiro, said Pedro Henrique Nobre, one of the authors of the crocodiles' scientific description.
An adult measured about 10 feet (3 meters) from head to tail and weighed around 900 pounds (400 kilograms), making it the largest crocodile species ever discovered in South America, Nobre said.Unlike modern crocodiles, the Baurusuchus had long legs and spent much of its time walking.
It also could live in arid areas where water was scarce, like other carnivorous creatures of the epoch, Nobre said. "The skeleton was exceptionally well-preserved."
Scientists were able to separate the fossil's jaws and see how the Baurusuchus used its big teeth to chew its prey, he said.
"It's the best-preserved fossil in this family. The ribs are intact and practically all the bones are preserved."
Scientists were led to the fossils by elementary-school teacher Joao Tadeu Arruda, who dug them up himself after one of his students showed him a fossilized tooth near the southwestern city of General Salgado.
Brazil has drawn international attention for its recent discoveries of prehistoric creatures. In January, the same team of scientists unveiled a replica of another prehistoric crocodile species, Uberabasuchus terrificus, which lived along the Sao Paulo coast around 70 million years ago.
In December, scientists unveiled a replica of Unaysaurus tolentinoi, an ancestor of the huge Brontosaurus that lived 230 million years ago in what is now southern Brazil. Experts said it was more closely related to fossils found in Germany than to dinosaurs from neighboring Argentina.
40 million-year-old fossil fills in evolutionary gap
February 24, 2005 - MSNBC
A new species of crocodile which lived 40 million years ago has been discovered in tropical Australia, filling a gap in the evolution of the prehistoric-looking crocodile, researchers said on Thursday.
Two nearly complete skulls and a lower jaw of a new species of crocodile that belonged to a group called Mekosuchinae were unearthed by miners in the northern state of Queensland, said Australia's Monash University researcher Lucas Buchanan.
"There is a big gap from about 30 to 60 million years ago of which we have no clue, except for these guys," Buchanan told Reuters on Thursday.
Buchanan said the new species of crocodile was living in the early Tertiary period, from 65 million years ago until five million years ago, during which time climate change possibly had a major impact on the evolution of the modern-day crocodile.
During the period, Australia and Antarctica broke apart and most of eastern Australia became warmer, leading to an increase in rainforests -- an ideal environment for crocodiles.
Buchanan said the new species of crocodile was very similar to the modern-day freshwater crocodile, suggesting the modern crocodile had changed little in millions of years of evolution.
"This croc would have looked much like a modern freshwater crocodile, which is the beautiful thing about crocodiles. They found something that works and stuck with it all through history," he said.
However, the ancient crocodile had sharper and laterally compressed teeth enabling it to sheer prey and an extra jaw muscle to give a stronger, more powerful bite.
Buchanan said researchers were examining more crocodile fossils and hoped to add to the crocodile evolution puzzle.
"It will also help us place this unique Australian group with the bigger picture of where they fit in with other lines of crocodiles," he said.
110 million year old "SuperCroc" Fossil Found in Sahara National Geographic - October 2001
The giant creature, which lived 110 million years ago, during the
Middle Cretaceous, grew as long as 40 feet (12 meters) and
weighed as much as eight metric tons (17,500 pounds).
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