Eoraptor is one of the earliest known dinosaurs. This creature was discovered in 1991 by a group of students doing research in Argentina, and was named by Paul Sereno.
Eoraptor was a lightweight predator with hollow bones, much like modern day birds. Its teeth were suited for eating small animals such as lizards, and worms.
All though smaller, his small predator dinosaur was constructed much like later predator dinosaurs, with small forelegs, and large hind legs allowing it to walk and run bipedally.
Anchisaurus was originally discovered in 1818, many decades before the Dinosaurs were officially recognized.
At that time, scientists believed that the skeleton was that of an early Human.
This dog sized animal probably hoped along slowly similar to a Kangaroo, as it foraged around looking for plant life.
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|aurornitholestes langstoni (Langston’s lizard-bird thief) is a coyote-sized carnivorous dromaeosaurid dinosaur genus from the Upper Cretaceous (Upper Campanian) of Alberta, Canada. Several incomplete skeletons, dozens of isolated bones, and scores of teeth are known from the badlands of Dinosaur Provincial Park in Albertamost of these are housed at the Royal Tyrrell Museum of Palaeontology, in Drumheller, Alberta.|
|Like other theropods in the family Dromaeosauridae, Saurornitholestes had a extended, curving, bladelike claw on the second toe. Saurornitholestes was more long-legged and flippantly built than other dromaeosaurids such asVelociraptor and Dromaeosaurus. It resembles Velociraptor in having large, fanglike teeth in the face of the jaws.Saurornitholestes most intimately resembles Velociraptor, although the precise relationships of the Dromaeosauridae are still comparatively poorly understood.|
|Saurornitholestes appears to have been the most ordinary small theropod in dinosaurProvincial Park and teeth and bones are much more ordinary than those of its more massive contemporary, Dromaeosaurus. Little is known about what it ate and how it lived, but a tooth of Saurornitholestes has been found entrenched in the wing bone of the pterosaur Quetzalcoatlus. Whether it in fact killed the pterosaur or merely scavenged an already dead animal is unknown.|
|Similar teeth are established in younger deposits, but whether they stand for S. langstoni or a different, related species is unknown.|
|Other scientists think the extensive volcanic activity in India known as the Deccan Trapsmay have been responsible for, or contributed to, the extinction. However, paleontologists remained skeptical, as their reading of the fossil record suggested that the mass extinctions did not take place over a period as short as a few years, but instead occurred gradually over about ten million years, a time frame more consistent with massive volcanism. There was also a certain general distrust of a group of physicists intruding into their domain of expertise.|
|A very large impact crater has been recently reported in the sea floor off the west coast of India.The researchers suggest that the impact may have been the triggering event for the Deccan Traps. However, this feature has not yet been accepted by the geologic community as an impact crater.
Extreme volcanic activity and the additional acid rainmay perhaps have altered the Earth’s climate sufficient to generate mass extinction. The delayed Cretaceous was a time of high tectonic action and additional volcanic action. The super continent Pangaea was splitting up and the continents were taking on their modern-day forms. Extreme volcanic activity would discharge dust and acidic chemicals (like sulphuric acid) into the atmosphere, which causes global cooling, and possibly, mass extinctions.
* Changes in the Earth’s orbit that might have caused climactic cooling might have caused the extinction. In this circumstance, the dinosaurs couldn’t acclimatize to the cold, but the hairy mammals could. This is steady with the type of weather in the late Cretaceous; toward the ending of the Cretaceous, there was a drop in sea level, causing land exposure on all continents, more seasonality, and greater extremes between equatorial and polar temperatures.
*Mammals eating dinosaurs’ eggs have been suggested as a cause of the K-T extinction. This doesn’t explain why so many other species went extinct, or why there are chemical anomalies in the K-T layer.
|* Large amounts of methane changing the Earth’s atmosphere (causing a greenhouse effect). The methane source would be from deep-sea algae deposits and/or from plant-eating dinosaur’s digestion by-products.
*The herbivorous dinosaurs’ over-foraging and the carnivorous dinosaurs over-culling of the herbivorous dinosaurs could have triggered mass starvation.
* A nearby supernova (an exploding star) could have bathed the Earth in deadly radiation.
|Stenonychosaurus (type genus S. inequalis) was named by C.M. Sternberg in 1932, based on a foot, wreckage of a hand, and some caudal vertebrae from the Late Cretaceous of Alberta. An extraordinary feature of these remains was the distended claw on the second toe, now recognized as trait of Deinonychosauria. Sternberg initially classified Stenonychosaurus as a associate of the family Coeluridae within the theropod dinosaurs. Later, Sternberg (1951) speculated that since Stenonychosaurus had a “very peculiar pes” and Troodon “equally strange teeth”, they may be closely related. Unluckily, no comparable specimens were obtainable at that time to test the idea.|
|A more whole skeleton of Stenonychosaurus was described by D.A. Russell in 1969, which eventually shaped the scientific foundation for a famous life-sized sculpture ofStenonychosaurus accompany by its fictional, human-like descendant, the “dinosauroid”.Stenonychosaurus became a well-known theropod in the 1980s, when the feet and braincase were described in more elements. It is sometimes listed as the “most intelligent” of dinosaurs.P.J. Currie reviewing the known Troodontidae in 1987, reclassified Stenonychosaurus inequalis as a junior synonym of Troodon formosus. This synonomy has been extensively adopted by other paleontologists, and therefore all of the specimens once called Stenonychosaurus are now referred to as Troodon in the recent scientific text. Other taxa “lumped” into Troodon are Pectinodon bakkeri and Polyodontosaurus grandis, which, the length of withStenonychosaurus inequalis may all be separate suitable species, or belonging to one genus or species.|
Deinonychus antirrhopus (“counterbalancing terrible claw”) is a wolf-sized, carnivorous dromaeosaurid dinosaur class from the Early Cretaceous Clovery Formation of Montana. Its name, “Terrible claw”, refers to the enormous, sickle-shaped talons on the second toe. These claws were almost certainly held retracted while the dinosaur walked on the third and fourth toes. It was usually thought that Deinonychus would kick with the sickle claws to cut at its prey, but recent tests on reconstructions of alike velociraptor talons propose that the claw was used to stab, not slash. Like with all dromaeosaurids the tail was stiffened by a sequence of elongated bones (not tendons).
Based on the group of a number of Deinonychus skeletons in a single quarry — several hundred Deinonychus bones were exposed by paleontologist John Ostrom and Grant E. Meyer in 1964 in southern Montana — it has been speculated that Deinonychus lived in packs. This is quite likely, but it is difficult to prove or disprove this idea. Shed teeth of Deinonychus are often established alongside skeletons of the ornithopod dinosaur Tenontosaurus, representative that it fed on them, and perhaps hunted them.
John Ostrom named and described Deinonychus, and the detection of this clearly active, agile predator did much to change the scientific (and popular) beginning of dinosaurs and open the door to conjecture that dinosaurs may have been warm-blooded.
Several years later, Ostrom noted similarities between the hand of Deinonychus and birds, which led him to revitalize the hypothesis that birds are descended from dinosaurs. Thirty years later, this thought is almost universally accepted. Finds of related dinosaurs from China, such asSinornithosaurus and Microraptor point to that this dinosaur almost certainly bore feathers. Other relatives include Velociraptor, Utahraptor, and Dromaeosaurus.
A skeleton of Deinonychus can be seen on show at the American Museum of Natural History or the Harvard Museum of Comparative Zoology. The American Museum and Harvard specimens are from a dissimilar locality than the Yale specimens which Ostrom described, and the claws are dissimilar shapes (Ostrom 1976). This raises the option that the two are, in fact, different species or even different genera.
|Size:||Skull length: 410 mm (16 in)
Total length: 3 m (10 ft)
Hip height: 1.2 m (4 ft)
Weight: 80 kg (175 lb)
|Main Facts:||Renamed as “Terrible claw” .Its tail was stiffened by a sequence of elongated bones (not tendons).|
|Troodon formosus was a relatively small, bird-like dinosaur from the delayed Cretaceous time (68–65 MYA). Discovered in 1855, it was in the middle of the first dinosaurs found in North America, and is supposed to have been one of the most intelligent.|
This small dinosaur was approximately 2 m (6.5 ft) in length, 1 m (3 ft) tall and weighed 60 kg (130 lb). Its eyes were big (suggesting nocturnal activity) and slightly onward facing, giving Troodon some depth perception.
Troodon (pronounced “Tro-odon”) is Greek for “wounding tooth”, and refers to the dinosaur’s sharp teeth with jagged edges. Its diet consisted of smaller animals, counting mammals and perhaps a significant amount of plant material as well.
|Troodon was discovered by Ferdinand V. Hayden in 1855. Troodon’ had long arms that folded back like a bird’s, and its hands obsessed partially opposable thumbs. It had large, sickle-shaped claws on its second toes which were raised off the ground when running. This claw is common in the superfamily Maniraptora, to which Troodon belongs.|
Troodon has very long, slender limbs suggestive of that the animal was quite fast. Although at first thought to be a predator, there is some proof that Troodon may either have been an omnivore or an herbivore. The jaws get together in a broad, U-shaped symphysis similar to that of an iguana, and the teeth bear large serrations like those of herbivorous dinosaurs. In adding, the teeth are short but broad, and bear wear facets on their sides; in these respects Troodon is again more like plant consumption dinosaurs than carnivores such as Dromaeosauridae. A specimen of Troodon is known from Montana sitting atop a clutch of eggs.
|Antarctosaurus Dinosaur (southern lizard) was an herbivorous titanosaur, which existed, in the late Cretaceous, around 75million year ago. This quadruped would have reached a length of around 18m, a height of 6m, and a weight of 40 to 70 tons, making it one of the largest South American sauropods and amongst the largest dinosaurs ever – it is related to the similarly gigantic Argentinosaurus.|
|Antarctosaurus is found in natural history museum and named by the paleontologistvon Huene.The first fossils were established in 1916, and others have since been found in India, Argentina, Uruguay, Chile, Brazil, Kazakhstan and Africa, and it is probable that it really did live in Antarctica. Parts recovered include two femora, two incomplete pelvises and numerous other fragments. One of the femora was 2.20m in length, and it is primarily from this that the astonishing size of the dinosaur is extrapolated. The post crania, however, suggest that its head was barely 60cm long.|
|The taxonomic classification of Antarctosaurus Dinosaurs is, like that of a lot of dinosaurs, highly disputed. The type specimen may in fact be a small Antarctosaurus, as another specimen has recently been recovered that its double the size of the type specimen.|
|Originally this dinosaur was located in a separate species, but they are now both thought to be A. wichmannianus. There are other problems with the type specimen, counting that its lower jaw is now thought to belong to a rebbachisaurid. Whether Antarctosaurus is even a titanosaur at all is now uncertain; it was located into Diplodocidae in 1993, but returned to Titanosauridae in 1997. Also, Jainosaurus was originally consideration to be a species of Antarctosaurus, A. septentrionalis, but it is now recognized as a distinct genus.|
|For many decades, Brachiosaurus (brack-ee-oh-SORE-us) was the biggest dinosaurs known. It has since been exceeded in sheer mass by a number of giant titanosaurids like theArgentinosaurus and it was lastly surpassed in height by another brachiosaurid, the Sauroposeidon. It was, however, still the largest dinosaur known from a fairly complete skeleton.|
|However, even that may no longer be true, since the biggest known specimens are now considered to be part of the new Giraffatitan genus. This new species includes the well-known mounted Brachiosaurus in the Humboldt Museum of Berlin, which is the tallest mounted skeleton in the world.
Brachiosaurus is unsurprising to weigh from 30 to 80 tones (35 to 90 tons), to reach 13 meters (42 feet) in height, and 25 meters (82 feet) in length. Higher estimates are usually based on theUltrasauros, which was originally measured to be an extremely large Brachiosaurus.
|However, Ultrasauros is now believed to be a chimera, calm of neck bones from a Supersaurus, and a shoulder bone (scapulacoracoid) from a Brachiosaurus smaller than the largest Giraffatitan specimens.|
|Description and environment
Brachiosaurus had teeth like chisels (spatulate), and nostrils on the top of its head, which may indicate it, had a good sense of smell. It had a number of holes in its skull to decrease weight. The first toe on its front foot, and the first three on its hind feet had claws. They may have traveled in herds.
It used to be theorized that it used the nostrils on the top of its head like a snorkel, and spent most of its time flooded in water to help support its great mass. However, it is now believed that it was a fully earthly animal. Studies have shown that the water pressure would be too great for it to breathe while flooded, and its feet are too narrow, and would sink into the mud.
Like all of the other “long-necked” dinosaurs, the Brachiosaurus’ neck was serious and when it held it in a upright position for too long time, it would not get any blood to the brain. It might have stood at the border of the forests and waved the head up and down, while it systematically detached all the eatable food on the trees.
If the Brachiosaurus was warm-blooded, it is predictable that it would take ten years to reach full size. If it were cold-blooded, then it would take over 100 years to do so. If it were warm-blooded, it would have to eat more than 400 lbs. (200 kg) a day, but a lot less if it were not.
|Berlin’s brancai and Chicago’s high flyer
The mounted skeleton of a B. brancai (or Giraffatitan) in the Humboldt Museum in Berlin is 4 stories tall, attainment 12 meters (39 feet) into the air, and is 23 meters (74 feet) long. It is the tallest mounted skeleton in the world, although the bones come from several different specimens.
A Brachiosaurus is also mounted in the B Concourse of United Airlines’ Terminal One in O’Hare International Airport in Chicago, politeness of the Field Museum of Chicago. It is a model, not a collection of fossils.
Brachiosaurus has three known species:
B. alataiensis de Lapparent & Zbyszewski, 1957: Is known from back bones (vertebrae), and parts of the hip and limbs, which were improved in Estremadura, Portugal. It lived about 150 million years ago, during the Kimmeridgian age of the late Jurassic period.
B. altithorax Riggs, 1903: The type species is known from two part skeletons recovered in Colorado and Utah in the United States. It lived from 145 to 150 million years ago, during the Kimmeridgian to Tithonian ages.
B. nougaredi de Lapparent, 1960: While it may not be a separate species (nomen dubium?) it is known from set of compound bones over the hip (sacrum), and parts of a forelimb, which were improved in Wargla, Algeria in Africa. It lived 100 to 110 million years ago, during the Albian to Cenomanian ages of the center Cretaceous period.
|The best specimens of Brachiosaurus were from the species B. brancai, which was found in the Tendaguru Beds of Tanzania, in Africa. In 1991, George Olshevsky located them in a new genus, Giraffatitan because they share no resulting characteristics with Brachiosaurus. Giraffatitan has withers over its shoulder and a rounded crest over its nostrils.
Giraffatitan brancai Janensch, 1914 (formerly B. brancai): The new type species, it is known from five incomplete skeletons, including at least three skulls, and some limb bones, which were healthier in Mtwara, Tanzania, in Africa. It lived from 145 to 150 million years ago, during the Kimmeridgian to Tithonian ages of the late Jurassic period.
The first Brachiosaurus was exposed in 1900 by Elmer S. Riggs, in the Grand River Canyon of western Colorado, in the United States. He named the new species and genus in 1903 after its long front limbs — Brachiosaurus means “arm lizard”, from the Greek brachion (“arm”) and sauros (“lizard”).
Starting in 1909, Werner Janensch establishes many new specimens in Tanzania, Africa, including some nearly whole skeletons, which were extensively used in Brachiosaurus reconstructions. These are now measured to be Giraffatitan fossils.
|Allosaurus Dinosaur (AL-oh-sore-us) was a big carnivorous dinosaur with a length of up to 12 m (39 ft).It was the most common huge predator in North America, 140 million years ago, in the Jurassic period.
Allosaurus Dinosaur is the official state fossil of Utah, in the United States.
|Allosaurus is a classic big theropod: a big skull on a short neck, a long tail, and abridged forelimbs. Its most distinctive feature is a pair of blunt horns just above and in front of the eyes. Although short in assessment to the hindlimbs, the forelimbs are massive and bear large, eagle-like claws. The skull shows evidence of being self-possessed of separate modules, which could be moved in relation to one another, allowing big pieces of meat to be swallowed. The skeleton of Allosaurus, like other theropods, shows birdlike features similar to a wishbone and neck vertebrae hollowed by air sacs. It is thought that Allosaurus might have necessary in packs, allowing it to bring down the huge sauropods of the time.|
Allosaurus Dinosaur is the most general theropod in the huge section of dinosaur-bearing rock in the American Southwest known as the Morrison Formation. Remains have been improved in Montana, Wyoming, South Dakota, Colorado, Oklahoma, New Mexico, and Utah in the United States; and in Portugal. Curiously, Allosaurus shared the Jurassic landscape with several other theropods, including Ceratosaurus and the massive Torvosaurus.
A famous fossil bed can be found in the Cleveland Lloyd Quarry in Utah. This fossil bed contains over 10,000 bones, mostly of Allosaurus, with other dinosaurs like Stegosaurusand Ceratosaurus thrown in. It is still a mystery how the bits and pieces of so many animals can be found in one place: normally the ratio of fossils of carnivorous animals over fossils of plant eaters is very small. Conclusion like these can be explained by pack hunting, although this is difficult to prove.
One of the more important finds was the 1991 discovery of “Big Al” (MOR 593), a 95% comprehensive, partially articulated, juvenile specimen that measured 8 meters (26 feet) in length. Nineteen bones were broken down or showed signs of infection, which probably contributed to Big Al’s death. It was featured in the BBC’s Walking with Dinosaurs series in the “Ballad of Big Al”. The Museum of the Rockies and University of Wyoming Geological Museum excavated the fossils near Shell, Wyoming. This skeleton was at first discovered by a Swiss team led by Kirby Siber,which later excavated a second Allosaurus “Big Al Two”, which is the best preserved skeleton of it’s kind to date.
|Classification and history of Allosaurus Dinosaur
The first Allosaurus Dinosaur fossil to be described was a “petrified horse hoof” given to Ferdinand Vanpeer Hayden in 1869 by the populace of Middle Park, near Granby, Colorado. It was really a caudal vertebra (a tail bone), which Joseph Leidy tentatively assigned first to the Poicilopleuron genus, and later to a new genus, Antrodemus. However, it was Othniel Charles Marsh who gave the formal name Allosaurus fragilis to the genus and type species in 1877, based on much better material counting a partial skeleton, from Garden Park, north of Canon City, Colorado.
The name Allosaurus Dinosaurs comes from the Greek allos, meaning “strange” or “different”; and sauros, meaning “lizard” or “reptile”. The species epithet fragilis is Latin for “fragile”. Both refer to lightening skin in the vertebrae.
It is unclear how many species of Allosaurus Dinosaurs there were. The fabric from the Cleveland-Lloyd Allosaurus is much smaller and more lightly built than the huge, robust Allosaurus from Brigham Young University’s Dry Mesa Quarry. Fossils like Allosaurus have been described from Portugal.
Allosaurus’s closest relative is probably the Lower Cretaceous Acrocanthosaurus.