|Two New Dinosaurs Discovered in Antarctica|
|"Working in some of
the planet's harshest conditions, fossil hunters have found two completely
new species of dinosaur in Antarctica. This increases to eight the number
of dinosaur species found on the perpetually frozen southern landmass."
here: Two New Dinosaurs Discovered in Antarctica
|New Madagascar Dinosaur Discoveries|
About 70 million years ago, the nearly complete skeleton of a young dinosaur was fossilized on the supercontinent of Gondwanaland on what is now called the island of Madagascar. This was a time when the last of the giant sauropod dinosaurs were at the height of their development. The fossil included almost a complete set of 80 to 90 vertebraefrom the neck, back, hip, and tail as well as a complete skull. The young dinosaur measured 26 feet long from head to tail and "probably weighed about as much as an elephant," one of the team members from Stony Brook University in New York, Curry-Rogers said. Because it was a juvenile, she noted, it was only about half the size of an adult titanosaur. Fully grown, a titanosaur would be about 50 feet long.
Titanosaur's are a sub-group of the long-necked, plant-eating sauropods. Other sauropods included the closely related Brachiosaurus, Apatosaurus, and Diplodocus.
More than 30 kinds of titanosaurs have been identified so far. Yet according to Curry- Rodgers, how they were related and what they looked like has been difficult to figure out because until this discovery no one had found a complete skull or skeleton.
"Since the first titanosaur was found a hundred years ago, weve had no idea of their anatomy. The most important thing about this discovery is that it gives us our first idea of what a titanosaur looked like from head to tail."
The researchers named the new dinosaur species Rapetosaurus krausei. The first part of the name, another researcher explained, comes from the Malagasy word "Rapeto." It's the name of a mischievous, mythical giant of Madagascar, a figure somewhat like Paul Bunyan, a giant woodcutter in American folklore.
"Since this new species is one of the dinosaur giants, we thought the name was fitting," she said. The second word in the scientific name was chosen in honor of expedition leader Krause. The two researchers said it had a very long neck, a short tail, and a long, narrow snout. The new skull show that the nostrils were on top of its head, rather than at the sides of its snout, like in horses and dogs.
The teeth of Rapetosaurus were "pencil-like pegs," Curry-Rogers said. "It's teeth were okay for raking leaves off trees, but it can't crunch and wasn't a very efficient eater," she explained. Included among the fossils were the partial remains of two other dinosaur species besides Rapetosaurus that are also new to science. "We've been fortunate enough to make one fantastic discovery after another, including some of the most complete and exquisitely preserved dinosaur material in the world," expedition leader Krause said. Previously, scientists had speculated that Africa, Madagascar, and other southern landmasses were relatively isolated during the 35 million years of the Late Cretaceous period and therefore had no dinosaurs like those that lived in other regions of the world at about the same time. The first significant dinosaur discovery by Krause and his colleagues, which came in 1996, challenged that idea. They uncovered the well-preserved skull of a giant meat-eating theropod, named Majungatholus, which is a relative of the American T rex.. Its features resembled those of dinosaur fossils found in present-day Argentina and India.
Several fossils belonging to the dinosaur Majungatholus, including an almost complete skull, were found from 1996 to 2000. The fossils date from 70 to 65 million years ago, during the late Cretaceous period, right before the huge K-T extinction in which the remaining dinosaurs, except the avian dinosaurs the birds, went extinct. Majungatholus atopus was a meat-eating dinosaur called a theropod. It was up to 30 feet long and was at the top of the food chain in its locale. It probably ate sauropods, like the recently named Titanosaur Rapetosaurus krausei. The name Majungatholus is derived from "Majunga," a district of Madagascar and "tholus," which means dome in Latin. Majungatholus belongs to the group of dinosaurs called abelisaurids, which until now were only found in India and South America. It is especially similar to the horned dinosaur Carnotaurus, which is found in Argentina. Finding this Majungatholus in Madagascar, far from its relatives in India and South America, has implications for plate tectonics like discussed above.
In particular, the continent of Gondwanaland may have had a connecting land-bridge from South America through Antarctica to India-Madagascar for longer than believed, allowing animals like Majungatholus to slowly migrate to new, far flung habitats.
This suggests that Madagascar may not have been long isolated but connected to South America by a land bridge, perhaps through Antarctica. Krause recently made another discovery in Madagascar that will add to that debate. In the August 2, 2000 issue of Nature, he reported finding a tooth in Late Cretaceous rocks that provides the first evidence of an ancient marsupial in Madagascar. It's intriguing because all of the island's mammals today are placental, and marsupials are thought to have originated in the Northern Hemisphere.
Until this new dinosaur discovery, it had been thought that Majungatholus (then only known from a skull fragment) was a pachycephalosaurid (a thick-skulled, plant-eating dinosaur) very similar to Yaverlandia bitholus, the oldest-known pachycephalosaurid which has been found in Britain. But it turned out that the fragment was not what it was thought to be and laid to rest a conundrum for paleontologists at that time.
The team that found the Majungatholus in Madagascar was led by paleontologist/anatomist Scott Sampson from the New York College of Osteopathic Medicine at the New York Institute of Technology. Further study by Raymond Rogers of Macalester College determined that when times got tough, the Majungatholus even ate his own kind. We have the smoking gun in the form of diagnostic tooth marks, and we can definitely rule out all the other carnivores known to have been on the scene, he stated firmly. What they are not sure of if this was predation, which would make them a definite cannibal, or simply scavenging anything in order to survive hard times.
Meanwhile, the skull and skeleton of the sauropod Rapetosaurus will help scientists better understand the links between different groups of titanosaurs and how they're related to other sauropods. Paleontologists had speculated, for example, that titanosaurs were closely related to Brachiosaurus. The Rapetosaurus fossils confirm that close relationship.
Another new Madagascar dinosaur discovery is related to the raptors. This new fossil, when alive, would have weighed about as much as a large dog. But the most unique feature of the newly discovered Masiakasaurus knopfleri is its teeth, some of which protruded from its jaw almost horizontally.
Scott Sampson, along with other paleontologists, discovered fossil evidence of this small carnivorous dinosaur on the island of Madagascar fairly recently. When we dug up the first lower jaw bone, we werent even sure it belonged to a dinosaur, said Sampson.
The Masiakasaurus knopfleris lower front teeth are nearly horizontal, with the teeth angle increasing until the dinosaurs fourth tooth, after which the teeth are vertical. Although the back teeth of the dinosaur are similar to other predatory dinosaurs, their horizontal, conical front teeth are otherwise unknown among other [predatory] dinosaurs, according to the Masiakasaurus discoverers.
This dinosaurs fossils were dated to the Late Cretaceous period (about 65-70 million years ago). They show a five to six-foot (about two-meter) long dinosaur that weighed about 80 pounds.
The name of the new dinosaur is derived from masiaka, the Malagasy word for vicious and sauros, which is Greek for lizard. Scientists on these Madagascar finds often incorporate local language words into the names of the newly discovered reptiles.
Knopfleri honors musician Mark Knopfler, lead singer of Dire Straits. The scientists credit Knopflers music as a lucky charm; it seemed that many of their most important discoveries were made whenever they were listening to his songs.
Finding fossils entails a heavy dose of serendipity,
said Sampson, and well take good luck any way we can get it.
|Four Winged Dinosaur|
A stunning set of six fossils discovered in China could rewrite our understanding of how and why birds first took to the sky. The fossils clearly show a small dinosaur that had flight feathers covering its legs, as well as tail and arms, forming an extra pair of wings never before seen by paleontologists.
News of the find comes just days after scientists published work showing that baby partridges flap their tiny wings to help them climb steep slopes, an insight that may explain why wings first evolved. Together, the two discoveries may represent one the most significant advances in the contentious study of avian evolution for decades.
"We need to be prepared to change some cherished notions" about the evolution of flight, paleontologist Larry Witmer of Ohio University told a New Scientist reporter.
Experts have traditionally been split between two mutually exclusive theories. Flight either began with small, fleet predatory dinosaurs leaping from the ground into the air, or with other animals that learnt to fly whilst jumping to earth from trees. But the new studies reveal a far more complex picture.
The six new specimens "are potentially as important as Archaeopteryx," the famous feathered fossil discovered in the1860s. It first alerted scientists to the link between dinosaurs and birds, says Kevin Padian of the University of California at Berkeley. The Chinese fossils are of a small dinosaur belonging to the Microraptor genus. It is known to be the most primitive dromeosaur, a group of two-legged predatory dinosaurs closely related to birds. The four-winged dinosaur lived 130 million years ago
Earlier Microraptor fossils did not preserve feathers. But the best of the six new specimens, thought to belong to a new species, have the most extensive coat of feathers ever seen on a dinosaur. The animal was presumably light enough to fly - the best-preserved skeleton is just 77 centimeters from the nose to the tip of the long tail. There is "no doubt the new animal is a flying animal," says Xing Xu from the Institute for Vertebrate Paleontology and Paleoanthropology in Beijing, who describes the new fossils in Nature Magazine. Xu describes it as a "four-winged dinosaur". Instead of being capable of powered flight, Xu believes that Microraptor used all four limbs to climb trees, and then glide back down again. But Microraptor gui, as it has been dubbed, is unusual because it has feathers at the ends of its arms and legs that are twice as long as those close to its body.
Usually animals have gliding surfaces that narrow, rather than widen, the further they are from the body. The feathers on the legs are particularly baffling, as they cannot spread wide enough to generate much lift.
Xu suggests they might have served as a stabilizer, but other scientists say we need more time to be sure. "This is so far out of the box that we need to sit back and figure out how this can work," says Witmer.
All articles above are taken from various internet and printed sources. They have been edited, paraphrased, quoted, and combined for our purposes. Any errors in doing so reflects on the museum and not the original writers.