Scientists Discover 3,000-Pound Gigantoraptor Dinosaur in Mongolia

hinese scientists have uncovered the remains of a gigantic, surprisingly birdlike, dinosaur in Inner Mongolia, China. And by gigantic they mean 3,000 pounds.
The scientists were surprised by its size because most assume that as dinosaurs got more birdlike, they got smaller.
It's 35 times heavier than similar feathered dinosaurs, which rarely exceeded a body mass of 90 pounds.
Xing Xu and his colleagues at the Chinese Academy of Sciences in Beijing describe the dinosaur in this week’s issue of Nature:
"A histological analysis suggests that Gigantoraptor gained this size by a growth rate considerably faster than large North American tyrannosaurs such as Albertosaurus and Gorgosaurus." Check out an image showing its bone growth after the

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DINOSAUR ANATOMY part 3

A dinosaur skeleton also reveals several features unique to dinosaurs.
These are found in no other animals, and because of this paleontologists can use them to identify a new fossil as a dinosaur.
For example, dinosaurs had jaw muscles that extended out onto the top of the skull, through the highest opening behind the eye.
The humerus (first bone in the arm) had a long, strong ridge for the attachment of a large muscle.
There is also a distinct process at the knee joint, for the attachment of another muscle.
Other features are not unique to dinosaurs—they can be found in some other animals—but do serve to help distinguish dinosaurs from most other reptiles.
The limbs of dinosaurs were held upright, like those of birds and mammals.
This is clear from the fact that the femur (thigh bone) was straight and had a distinct head, which stuck out from the shaft and directly into the hip socket.
The ankle was a hinge joint, only allowing back-and-forth motion. Dinosaurs also walked on their toes (this is called digitigrade posture), with the ankle held well off the ground.
In addition, the dinosaur hip socket was open, and did not have any bony wall along the inside. The neck tended to be long and curved. In the hand, the longest finger was the second, whereas in the foot the longest toe was the third.

Edmontosaurus mounted skeleton
Thus each particular feature of a dinosaur tells us something about the evolutionary history of the animal.
Most of what you see in a dinosaur comes from some point in its ancestry, either close or distant. Other features help to distinguish dinosaurs from all other animals, and still others can identify each type of dinosaur

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DINOSAUR ANATOMY part1

Because dinosaurs are also craniates (within vertebrates), they have a specialized head at the front of the body.
This head contains the brain, an enlarged nerve organ at the front of the spinal cord that encompasses three sensory capsules. These capsules detect light, smell, and sound, relaying this information to the brain.
The skull of a dinosaur, like your own, contains specific regions to house each of these sensory functions.
Dinosaurs also had specific organs associated with each sensory capsule: eyes for sight, ears for hearing, and a nose for olfaction. Specialized nerves led out from the brain to various parts of the body, the paths of which can sometimes be seen in dinosaur skull bones.
As gnathostomes, dinosaurs had hinged jaws that could open and close the mouth.
The scapula or shoulder bone of the forelimb was connected by muscles to the rib cage, but the pelvis or hip bone of the hind limb was firmly attached to the backbone. Semicircular canals in the inner ear helped the animal to maintain its balance.
Dinosaurs also had dermal bones (such as armor, as well as the outer skull bones), another gnathostome characteristic.
Because dinosaurs are tetrapods, their limbs had feet and hands.
The forelimb was suspended on the ribcage, but the pelvis was firmly attached to the vertebral column. Among tetrapods, dinosaurs are amniotes.
Thus they produced hard-shelled eggs with gas-permeable shells, which had to be laid on land. They did not have gills at any stage in their lives, and their skin was probably dry and scaly rather than moist and permeable.
As diapsid reptiles, dinosaurs had two openings in the skull behind the eye, one near the skull roof and another near the jawline.
As archosaurs, they had an extra opening in the skull between the nose and eye, and another in the lower jaw.

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DINOSAUR ANATOMY part1

The anatomy of a dinosaur includes both general and specialized components.
Most of the obvious features of dinosaurs were inherited from their ancestors, and as such, they often characterize not only dinosaurs but other animals as well.
They also provide clues that scientists can use to determine how dinosaurs are related to other animals. More specific anatomical features may characterize only dinosaurs, or only particular kinds of dinosaurs.
At their most basic level, dinosaurs are multicellular eukaryotes.
This means that dinosaurs were built out of many millions of cells, each of which had a distinct nucleus containing the dinosaur's genetic material.
Dinosaur reproduction was sexual, in which male and female gametes combined to create an embryo.
Even though we have no fossils preserving this tiny level of detail, scientists can infer these qualities of dinosaurs because they are present in all multicellular eukaryotes.
Within eukaryotes, dinosaurs are deuterostomes.
Therefore, like echinoderms, acorn worms, and vertebrates, dinosaurs would have developed from an embryo according to a certain pattern.
Specifically, the anus would have developed first and the mouth second. A long digestive tract would have connected the two openings.
Many of the most obvious features of dinosaur anatomy exist because dinosaurs are chordates and vertebrates.
As chordates, dinosaurs had a tail (defined as the structures following the anus), heart, and a long, hollow nerve cord that ran down the back. In addition, they were segmented animals, which would have been reflected in their musculature. As vertebrates, dinosaurs had an internal bony skeleton that was constructed around a central chain of segmented bones, the vertebral column.
This chain protected the spinal cord. Internally, dinosaurs had organs such as the liver and kidneys. Dentine and enamel were present, forming teeth and scales.

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dinosaurs Origins and early evolution - part 3

The first few lines of primitive dinosaurs diversified through the Carnian and Norian stages of the Triassic, most likely by occupying the niches of groups that became extinct.
Traditionally, dinosaurs were thought to have replaced the variety of other Triassic land animals by proving superior through a long period of competition.
This now appears unlikely, for several reasons.
Dinosaurs do not show a pattern of steadily increasing in diversity and numbers, as would be predicted if they were competitively replacing other groups;
instead, they were very rare through the Carnian, making up only 1-2% of individuals present in faunas.
In the Norian, however, after the extinction of several other groups, they became significant components of faunas, representing 50-90% of individuals. Also, what had been viewed as a key adaptation of dinosaurs, their erect stance, is now known to have present in several contemporaneous groups that were not as successful .
Finally, the Late Triassic itself was a time of great upheaval in life, with shifts in plant life, marine life, and climate.
Crurotarsans, today represented only by crocodilians but in the Late Triassic also encompassing such now-extinct groups as aetosaurs, phytosaurs, ornithosuchians, and rauisuchians, were actually more diverse in the Late Triassic than dinosaurs, indicating that the survival of dinosaurs had more to do with luck than superiority.

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dinosaurs Origins and early evolution - part 2

When dinosaurs appeared, terrestrial habitats were occupied by various types of basal archosaurs and therapsids, such as aetosaurs, cynodonts, dicynodonts, ornithosuchids, rauisuchias, and rhynchosaurs.
Most of these other animals became extinct in the Triassic, in one of two events.
First, at about the boundary between the Carnian and Norian faunal stages , dicynodonts and a variety of basal archosauromorphs, including the prolacertiforms and rhynchosaurs, became extinct.
This was followed by the Triassic-Jurassic extinction event , that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians.
These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles.

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dinosaurs Origins and early evolution - part1

For a long time many scientists thought dinosaurs were polyphyletic with multiple groups of unrelated "dinosaurs" evolving due to similar pressures,but dinosaurs are now known to have formed a single group.
Dinosaurs diverged from their archosaur ancestors approximately 230 million years ago during the Middle to Late Triassic period, roughly 20 million years after the Permian-Triassic extinction event wiped out an estimated 95% of all life on Earth.
Radiometric dating of the rock formation that contained fossils from the early dinosaur genus Eoraptor establishes its presence in the fossil record at this time.
Paleontologists believe Eoraptor resembles the common ancestor of all dinosaurs;
if this is true, its traits suggest that the first dinosaurs were small, bipedal predators.
The discovery of primitive, dinosaur-like ornithodirans such as Marasuchus and Lagerpeton in Argentinian Middle Triassic strata supports this view; analysis of recovered fossils suggests that these animals were indeed small, bipedal predators.

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WHAT IS A DINOSAUR ? part-2

Dinosaurs generally had but one type of tooth, although the teeth of one dinosaur may be quite different from the next. Mammals, by contrast, have a variegated dentition including cutting, tearing and chewing teeth.
A dinosaur usually had longer hind limbs than forelimbs, reflecting its bipedal ancestry. Brachiosaurus, a close relative of our most common local dinosaur, is a noted exception.
Dinosaurs were basically land dwellers; they did not fly nor did they do a lot of swimming. Swamps were not popular with them, contrary to common belief.
As land dwellers, one of their most important features was a fully erect gait (see Figs. 5 and 8).
They did not sprawl, but walked with their legs straight under their bodies.
This fact is reflected in their hip joints, which were tight cylinder joints, and in their trackways, which were narrow___in some cases even pigeon-toed___with little sign of tail dragging.
They had high skulls and generally deep rib cages.
Many walked on two legs.
Some of the very large ones were four-legged; however, even the biggest may have been able to rear up on their hind legs when trying to reach high vegetation. There were many more plant-eaters than meat-eaters.
They generally laid hard-shelled eggs, but some may have borne live young.

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WHAT IS A DINOSAUR ? part-1

"Dinosaur" is a term freely used and, more often, misused by the public.
A dinosaur was not any four-legged creature that lived long ago. Neither was a dinosaur a flying reptile, or pterosaur, frequently referred to incorrectly as a bird.
Nor were marine reptiles (Fig. 10) like plesiosaurs, icthyosaurs, and mosasaurs swimming dinosaurs. And of course, the famous finback reptile Dimetrodon of Permian time was not a dinosaur either.
Although it is difficult to get a precise definition of a dinosaur that all paleontologists will accept, a general description is not too hard to provide.
The first dinosaur to be recognized as a giant extinct reptile was Iguanodon, found in England in 1822 by Mary Ann Mantell, a fossil hunter and the wife of Dr. Gideon Mantell, who later described it. In 1842, the noted British anatomist Sir Richard Owen, oddly an opponent of Darwin's Theory of Evolution, gave the official name "Dinosauria" to Iguanodon and two other extinct giant reptiles, Megalosaurus and Hylaeosaurus. From that time forth, dinosaurs have been a fixture in the public consciousness.
Whether seen as failures or successes, they have often appeared in our cartoons, our advertising, and as toys.

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Dinosaur history

Since the early part of the twentieth century, when local iron mining ceased, very few dinosaur bones have been recovered from Maryland and its environs. This is, for the most part, due to a lack of knowledge about local bones by the general public. In addition, modern excavation methods using large machines have removed workers from close contact with the ground. Two noteworthy but isolated discoveries took place in Washington, D.C. In 1898, some men digging a sewer at First and F Streets, S.E., found the remains of a carnosaur ("Dryptosaurus," or a related species). Workers found a very large legbone from Astrodon, a brachiosaurid, while building the McMillan Water Filtration Plant at First and Channing Streets, N.W. in 1942. There have been other finds at other locations, but much needs to be done. The bones are still here, but few people are looking for them!

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Dinosaur

ABOUT 225 MILLION YEARS AGO, a new group of reptiles appeared on Earth. Like all reptiles, they had waterproof, scaly skin and young that hatched from eggs. These were the dinosaurs. For the next 160 million years they ruled the Earth, before finally becoming extinct.

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Dinosaur Island

Jurassic Park may have been fiction, but the Isle of Wight, aka "Dinosaur Island," was the real deal. Around 130 million years ago, this island, now in the English Channel, was home to countless dinosaurs, mammals, sharks, lizards, frogs, salamanders and more.
Minus the blazing fires and floods that ripped through the place on occasion, it was a prehistoric animal paradise, with creatures basking near flowing rivers surrounded by lush coniferous forests.

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