Cause of death of dinosaurs

Our current thinking is that dinosaurs passed away due to the following sequence of events:

A large asteroid from space crashing to the earth, producing a large amount of debris in the atmosphere.

The high amount of debris created dirty "clouds" which blocked out the sunlight and reduced the amount of sunlight reaching the earth.

Because of the reduced sunlight, plants began to die off. These plants included those which served as the dinosaurs food. The dinosaurs also began to die off due to the lack of food.

Over time scientists have had several theories regarding the disappearance of Dinosaurs. As I mentioned this is the current idea.

Dinosaurs Like You've Never Seen Before!

Fighting Dinosaurs: New Discoveries from Mongolia features more than 30 of the best preserved and scientifically important dinosaur and other ancient animal fossils ever discovered in Mongolia's famed Gobi Desert. On view through the exhibition focuses on the "Fighting Dinosaurs" of Mongolia — one of the most famous fossil finds in the world. Never before seen in North America and designated a national treasure of Mongolia, are the two Fighting Dinosaurs a fierce Velociraptor that was apparently buried alive while attacking a plant-eating, shield-headed Protoceratops.

Also featured are many new specimens from Mongolia, including a number of species yet to be named, some of the most complete meat-eating theropod dinosaurs ever found, several nesting dinosaurs, and some of the finest lizard and mammal fossils ever discovered. These specimens have enhanced our understanding of life in the Gobi region 80 million years ago, and they shed new light on the rise of modern bird and mammal groups.

This exhibition showcases discoveries and research by Museum and Mongolian Academy of Sciences paleontologists over the last 10 years, and reflects the most current thinking on dinosaur traits, behavior, and evolutionary links to birds. Discoveries in China from just two years ago reveal that a number of dinosaur species had feathers; among the highlights of the exhibition are fully feathered models of Velociraptor (shown above) and a nesting Oviraptor protecting its eggs.

Mammals Grew Big After Dinosaurs Died Off: Analysis

Mammals began to grow much larger after dinosaurs became extinct 65 million years ago, a new study suggests.

An international team of researchers analyzed the fossils of major groups of land mammals on each continent and found that their size increased from a maximum of about 10 kilograms (22 pounds) when they shared the Earth with dinosaurs to a maximum of 17 tonnes (18.7 U.S. tons) after dinosaurs became extinct.

"Basically, the dinosaurs disappear and all of sudden there is nobody else eating the vegetation. That's an open food source and mammals start going for it, and it's more efficient to be an herbivore when you're big," study co-author Jessica Theodor, an associate professor in the biological sciences department at the University of Calgary, said in a university news release.

The findings also show that the global ecosystem is able to reset itself relatively quickly.

"You lose dinosaurs 65 million years ago, and within 25 million years the system is reset to a new maximum for the animals that are there in terms of body size. That's actually a pretty short time frame, geologically speaking. That's really rapid evolution," Theodor said.

What was the biggest, smallest and smartest dinosaur?

The largest complete dinosaur we know of was Brachiosaurus ("arm lizard"); it reached 23 m in length and 12 m in height (about the length of two large school buses and the height of a four-story building). Fragmentary leg bones and vertebrae of even larger dinosaur species are known, but these skeletal remains are too incomplete to determine their exact size. Several of these (Argentinasaurus and Amphicoelias) might have been one and a half to two times larger than Brachiosaurus.

The smallest dinosaurs were just slightly larger than a chicken; Compsognathus ("pretty jaw") was 1 m (3 ft) long and probably weighed about 2.5 kg (about 6.5 lb). These three dinosaur types all lived during the Jurassic Period. Mussaurus ("mouse lizard") was claimed as the smallest dinosaur, but it is now known to be the hatchling of a dinosaur type that was much larger than Compsognathus when fully grown. If birds are advanced dinosaurs, then the smallest dinosaur would be the hummingbird!

Although there is no direct way to measure a dinosaur's intelligence, one of the few possible measures of intelligence might be a large brain in a small body. The genus that perhaps fits this description best was the Cretaceous bird-like dinosaur Troodon, which also may have had binocular vision (depth perception) and excellent eyesight and was built for speed. Even so, this dinosaur was probably not as "intelligent" as most modern birds and mammals.

Dinosaur World expansion to double size of desirability

PLANT CITY - Dinosaur World will break ground on an expansion plan to more than double the size of the tourist attraction.

The 12-acre expansion will comprise a 22,000 square-foot building to house a museum with a primitive theme, gift shop and office space. More dinosaur replicas will be added to the 150 previously at the attraction at 5145 Harvey Tew Road, just off Interstate 4 at Branch Forbes Road. A few woolly mammoth replicas may also be added.

Other new features will embrace a playground, more parking and bigger picnic areas.

Dinosaur World spokeswoman Nicole Randall said a few of the details won't be released but construction is predictable to be finished in fall 2011. The park, now 8 acres, will remain open throughout the expansion.

Dinosaur World, the brainchild of Swedish businessman Christer Svensson, opened in Plant City in 1998 on the position of the former Gator Jungle tourist attraction. Less than five years afterward, another site opened in Cave City, Ky.; in 2008, and a third opened in Glen Rose, Texas.

Most dinosaurs were vegetarian, research proposes

Most dinosaurs were vegetarian rather than meat-eating beasts, research suggests.

While Tyrannosaurus Rex sums up the image of a dinosaur wreaking terror by ripping flesh with powerful jaws, several of its closest relatives were more content nibbling leaves.

A new study of the diet of 90 species of theropod dinosaurs challenged the conservative view that almost all theropods hunted prey, particularly those closest to the ancestors of birds.

Rather it showed that among the most bird-like dinosaurs known as coelurosaurs plant eating was a frequent way of life.

Their diet may have also assisted them survive and use new environments becoming the most winning group of dinosaurs throughout the Cretaceous Period, 145-65 million years ago.

Dr Lindsay Zanno of the Chicago Field Museum said: "Most theropods are obviously adapted to a predatory lifestyle, but somewhere on the line to birds, predatory dinosaurs went soft."

Among theropod dinosaurs, all modern birds and numerous groups of their neighboring extinct relatives belong to a subgroup known as Coelurosauria.

Most were feathered and most clever dinosaurs and those with the smallest body sizes also belong to this group.

Though researchers have been only left with fossilized bones and teeth to work with and so had to infer their diets.

Most bird-like dinosaurs ate plants, latest study discovers

The results are in sharp contrast to a widespread belief among paleontologists who say theropod dinosaurs sought their prey.

Lindsay Zanno and Peter Makovicky of the Field Museum in Chicago used statistical analysis to conclude that 90 species of theropod dinosaurs ate a plant-based diet, particularly among coelurosaurs, the mainly bird-like dinosaurs.

The results were in sharp contrast to a widespread faith among paleontologists who say theropod dinosaurs hunted their prey, particularly those closest to the ancestors of birds.

"Most theropods are obviously adapted to a predatory lifestyle, but someplace on the line to birds, predatory dinosaurs went soft," Zanno explained.

Zanno and Makovicky found almost two dozen anatomical features were statistically linked to direct facts of plant eating among coelurosaurian dinosaurs, such as the loss of teeth or a long neck.

"Once we linked convinced adaptations with direct evidence of diet, we appeared to see which other theropod species had the same traits... Then we could say who was expected a plant eater and who was not," added Zanno.

During their analysis, the researchers establish that 44 theropod species distributed across six major lineages ate plants and that the ancestor to most feathered dinosaurs and modern birds had most likely already stopped eating meat only during the Cretaceous Period, some 145-65 million years ago.

In light of the huge number of plant eaters during that period, the carnivorous diet of T. rex, Velociraptor and other meat-eating coelurosaurs should be viewed "more as the exception than the rule," Zanno said.

"It’s time to start considering these animals in a new evolutionary context," Zanno said.

The researchers also recommended that these large predators and their close relatives may have in fact evolved from omnivorous ancestors.

Not Meat-eating dinosaurs so carnivorous after all

New research by Field Museum scientists discovers widespread herbivory in bird-like theropod dinosaurs. Four of the 90-theropod species concerned in the study shown with dietary interpretations. All four species derive from the prominent feathered dinosaur beds of the Early Cretaceous Yixian Formation, P. R. China, leading the scientists to wonder that dietary diversity may have contributed to the huge numbers of contemporaneous theropods in ecosystems like those of the Yixian.

Field Museum scientists used statistical analyses to establish the diet of 90 species of theropod dinosaurs. Their outcomes challenge the conventional view that almost all theropods hunted prey, particularly those closest to the ancestors of birds.

Tyrannosaurus rex may have been a flesh-eating terror however many of his closest relatives were more content with vegetarian fare, a fresh analysis by Field Museum scientists has established.

Theropods are a group of bipedal dinosaurs colloquially identified as "predatory" dinosaurs. Among theropod dinosaurs, all modern birds and numerous groups of their closest extinct relatives belong to a subgroup known as Coelurosauria. Coelurosauria also comprises the iconic hunters Tyrannosaurus and Velociraptor. Most coelurosaurs were feathered and the cleverest dinosaurs and those with the smallest body sizes also belong to this group.

Raptor-like dinosaur revealed in eastern Utah

A little, feathered raptor-like dinosaur thought to be 125 million years old has been discovered in eastern Utah.

The Geminiraptor suarezarum was bipedal and, similar to other raptors, had a large head. The majority of the known raptors discovered in North America date to between 72 million and 75 million years ago, which builds the discovery the oldest reported specimen of its kind.

"They were speedy, they were smart, they had large eyes and very dexterous hands," said James Kirkland, a paleontologist with the Utah Geological Survey.

It was the eighth new species of dinosaurs revealed in Utah this year. Seven of those were establish on federal land.

Therizinosaur—Mystery of the Sickle-Claw Dinosaur

How did this dinosaur get buried in mud at the bottom of the Cretaceous Western Interior Seaway? One hypothesis: Lost at sea, perhaps swept away by winds or change in currents, flailing about to protect itself from plesiosaurs and sharks until it could no longer stay afloat. An alternate hypothesis: Bloat and float. Illustration by Victor Leshyk.

Mounted skeleton of Nothronychus, the sickle-claw dinosaur from the Tropic Shale of southern Utah. The small head, tiny teeth, massive claws on the hands, expansive belly, broad hips, and short tail distinguish this dinosaur from all of its carnivorous relatives. Height as mounted is about 8 1⁄2 feet, but would be 13 feet tall in a more erect posture.

Reconstruction of Nothronychus on land. Although volcanoes are a cliche in dinosaur art, volcanic ash in the Tropic Shale indicates proximity of tectonic activity on land where these dinosaurs lived. Several Pteranodon soar safely overhead. Illustration by Victor Leshyk.

Jurassic Park Triceratops Discovery Trail restart at Islands of Adventure

After more than a few years of being closed, Jurassic Park Triceratops Discovery Trail has once again opened the paddocks and is welcoming guests. The attraction, part of the Jurassic Park area of the park, opened its doors this morning after months of conjecture. It’s one of the innovative attractions that made Islands of Adventure “The world’s most technologically advanced theme park”.

Discovery Trail, also known as Trike Encounter, permits guests to get up close and personal with creatures that have been died out for 65 million years. The experiences vary from permitting the guests to get sneezed on, to inspection the creatures pee, to even petting the dinosaurs. It’s a greeting sight as Universal gears up for what is sure to be its busiest Holiday Season ever, due to the opening of the Wizarding World of Harry Potter.

Currently with the opening of the Wizarding World of Harry Potter, the attraction has seen a new life, albeit that of a walkthrough to assist alleviates some of the huge crushing crowds that will surely encase the park over the Christmas Holiday. The original queue line is not unlocked with all the great videos and monitors, and again it is a stripped down version of its former self. With any fortune the park decides to stay this attraction open and finally return it to its former glory, because who doesn’t desire to touch a Dinosaur?

Archaeopteryx

Living a few 150 million years ago, Archaeopteryx sported feathers and a saurine skeleton. Standing on the brink among dinosaurs and birds, Archaeopteryx has long symbolized the concept of transitional species so instinctively significant in the acceptance of Darwin’s theory of natural selection. Its fossils have been museum beloved ever since the first fossil feather of the so-called Urvogel or “first bird” was discovered Germany in 1860.

The image above demonstrates the so-called Berlin Archaeopteryx unearthed in about 1875, the most complete fossil representative of the species we have. But it’s worth bearing in mind that what we see here is not the creature, nor an anatomical specimen set from an extant animal. A fossil is an image; after the body comes to rest in moist sediments, minerals fill in and put back organic compounds lost to decompose, forming a type of photograph-in-stone of a creature’s most durable anatomy.

When paleontologist Christian Erich Hermann von Meyer explained the fossil feather in 1861, he named the species Archaeopteryx lithographica—the specific epithet a recognition of the significance of an image-making process found in the Earth’s crust. But similar to any graphic medium, the fossil record is prejudiced and incomplete; only certain type of creatures in certain environmental conditions ever attain the timeless apotheosis of fossilization. Earth’s picture album of life is extremely informative, and yet partial.

Dinosaur fish be just 80 minutes away

Joseph Hatcher points to a yellow-coloured layer — the Gama Ferruginous Member of the Pierre Shale — on the Cretaceous Stratigraphic Nomenclature map of Southwestern Manitoba that’s taped to a wall.

We’re repute in the lab of the Canadian Fossil Discovery Centre in Morden, about 80 minutes southwest of Winnipeg on Highway 3.

"This is major because it was not before known to exist in Manitoba prior to this season in the area south of Riding Mountain National Park," says Hatcher, the CFDC’s assistant curator.

Xiphactinus was a gargantuan, voracious predatory fish that lived 80 million years ago in the Western Interior Seaway of North America throughout the Cretaceous period, sharing the waters with mosasaurs and other marine reptiles.

A display case keeps the lower jaw from this fearsome fish, which, with its sharp jutting teeth and blunt head is frequently said "to resemble a bulldog" adds Hatcher.

Formerly known as the Morden and District Museum (1971-2004), the 16,000-square-foot CFDC, located in the lower level of the Morden Community Centre, contains the biggest collection of marine reptile fossils in Canada, says Hatcher, a native of Hendersonville, N.C., who has been effective at the CFDC for the last three years.

Inside the centre’s collection room, Hatcher pulls out a drawer from a sizeable wooden cabinet and demonstrates me the upper jaw of a mosasaur with a row of sharp conical teeth.

It was excavated in the Manitoba Escarpment, as were the extra fossils in the CFDC, in 1978.

"Mosasaurs were air breathers and had extremely mobile jaws that could unbalance to engulf their unlucky victims," Hatcher explains.

"Horse Dragon," Colossus Dinosaurs establish in Utah

A shield-toothed horse-dragon may sound similar to a mythical creature, but the recently portrays dinosaur once roamed the U.S. West, a new study says.

The 125-million-year-old herbivore Hippodraco scutodens—whose partial skull and skeleton were unearthed in 2004 in eastern Utah—has a long, low skull similar to a horse's and a mouth filled with shield-shaped teeth.

Hippo and draco are Latin for "horse" and "dragon" correspondingly, while scutum means "oblong shield" and dens means "tooth."

Also exposed just, fossils of another recently described species from the same time period, Iguanacolossus fortis, were found in 2005 not far from Hippodraco.

That "ponderous beast" is named for its comparatively large size—about 30 feet (9 meters) long, compared with Hippodraco's 15 feet (4.5 meters), according to the study.

Iguanacolossus's teeth look like those of Iguanodon, a related, 33-foot (10-meter) North American herbivore that possible lived a few million years before Hippodraco.

Both of the newfound dinosaurs are iguanodonts, an "extremely successful" group of plant-eaters that prolonged worldwide during the early Cretaceous period, the study team wrote.

Despite their abundance, North American iguanodonts from this period are rare in the fossil record—excluding in one Utah rock formation, which spans about 40 million years and includes fossils of many types of creatures, according to study leader Andrew McDonald, a graduate student at the University of Pennsylvania.

Scientists determine 'Koreaceratops': First Horned Dino from Korea

Triceratops has a new cousin -- one as of a distant continent, that is.

Scientists from South Korea, the United States and Japan just declared the discovery of a new horned dinosaur, based on an analysis of fossil evidence found in South Korea. Dubbed "Koreaceratops" after its country of origin, the new dinosaur fossil was found in 2008 in a block of rock beside the Tando Basin reservoir.

At roughly 5 to 6 feet long and weighing between 60 and 100 pounds, the animal was somewhat small compared to its geologically younger, giant relatives similar to North America's Triceratops.

Koreaceratops had a parrot-like face with a beak at the front of its jaws, representing it was an herbivore. The claws on its hind feet propose that it was bipedal and moved at a fairly rapid speed. Koreaceratops had a unique fan-shaped tail formed by long neural spines, which suggests it may have been a fine swimmer, and spent part of its time hunting for aquatic food.

It is one of the primary articulated dinosaurs known from Korea, said J. Ryan, curator and head of Vertebrate Paleontology at The Cleveland Museum of Natural History, who co-authored the research.

This is a rare find," said Ryan in a release publicizing the discovery. "Fossils of dinosaurs have not classically been found in this region, whereas proof of dinosaur eggs and footprints occur more commonly. This specimen is important because it fills in a missing 20 million-year gap in the fossil record between the origin of these dinosaurs in Asia and their first look in North America.

The recently identified genus, Koreaceratops hwaseongensis, lived about 103 million years ago throughout the late Early Cretaceous period. The specimen is the primary ceratopsian dinosaur from the Korean peninsula. The partial skeleton includes an important portion of the animal's backbone, hip bone, partial hind limbs and almost complete tail.

Troodon

Troodon is a relatively small, bird-like dinosaur from the Late Cretaceous period. Found in 1855, it was the first dinosaurs found in North America. Its species ranged widely, with fossil remains recovered from as far north as Alaska and as far south as Wyoming and even possibly Texas and New Mexico.Troodon formosus (from Greek troo - to wound and odon - tooth) was a small possibly maniraptoran theropod dinosaur whose eating habits are still uncertain. This taxon is commonly recognized during excavation from its distinctive small teeth with large denticles along the trailing margin. While the dinosaurs may have ranged upwards to 6 feet (2 meters) in length, many of them must have been the size of chickens or smaller. The teeth size nearby microsites (localities in which most of the fossils are  small, being less than an inch, or 2 cm in length. These fossils are often teeth) are nearly microscopic, ranging upward to a few mm in length. Why the teeth are so small is difficult to understand, unless they are from very young dinosaurs that might have been feasting on the rotting carcasses of Edmontosaurus.

• Found in: North America

• Anatomy: Relatively large brain, large eyes and stereoscopic vision. Lightly built but agile, could run faster than most other dinosaurs of the time. It had excellent co-ordination and vision.

• Length: 2 m

• Height: 1-1.5 m

• Weight (mass): About 40 kg

• Locomotion: Bipedal

• Food preference: Carnivore (small vertebrates, Lizards, mammals)

• Time period: Cretaceous (76-74 million years ago)

• Type of hip: Lizard hipped

• Dinosaur group: Theropod

• Remains: 1982 scientist in Alberta, Canada uncovered the fossilized brain case.

HETERODONTOSAURIDAE

"Heterodontosaurus ("different-teeth lizard") Heterodontosaurids are known only from Lower Jurassic rocks of southern Africa. They were small dinosaurs with a length of 1 to 1.5 meters that had uniquely shaped cheek teeth, chisel-shaped with tiny cusps restricted to the apex of the crown (unique to all dinosaurs). They also had canine-like teeth in the front part of the mouth that had a different shape than the chisel teeth.

1. Heterodontosaurus was 1.2 meters long, with short forelimbs and long hind limbs (considered to be bipedal).
2. Dental battery set in massive lower jaws and the teeth are usually heavily worn (thus a plant eater).
3. Long tail and short neck (typical of primitive ornithischian)
4. Ossified tendons in the back region (along the vertebrae)
5. Fusion of the fibula and tibia and their fusion to the tarsals, this stabilized the lower leg and ankle for fast running (bird-like feature - example of convergent evolution).
6. Hands stout and flexible (perhaps to grasp vegetation)
7. Large canines (tusk like)- may have been used for defense and display (this may be a sexual dimorphic feature, some heterodontosaurid skulls lack canines). The canines may also have helped to stabe and tear vegetation.


8. Bones found in arid paleoenvironments (deserts and arid alluvial fans).

Description

The Heterodontosaurus was a bipedal/quadrupedal dinosaur. Its diet was low-growing plants. It had three kinds of teeth while most dinosaurs only have one type. The names of the three types are sharp upper front teeth, long canine tusks and high-crowned cheek teeth. It had three toes that faced forward on each foot. They had muscular arms and each hand had three large clawed fingers and two small fingers.

Residence

The Heterodontosaurus was 4 feet (1.2m) long and weighed 5.5 pounds (2.5kg). It lived in South Africa Cape, Province and Lesotho Quthing during the late Triassic and early Jurassic Periods

Male and Female

Adult male Heterodontosaurus have sharp canine like teeth that they most likely used to threaten and/or bite other competing males. Females and young males probably did not have those teeth. Their predators included theropods and crocodilians. While running it was probably on two legs and its tail wagged back and forth furiously unlike later ornithopods whose tail would straight. "

HADROSAURIDAE

The Hadrosauridae are commonly known as the duck-billed dinosaurs. They first appeared in Medial Cretaceous time and were the last group of ornithopods to evolve. There is more known about this family than any other group of dinosaurs. Their fossil record includes many complete skeletons, eggs and nests, footprints, and two mummified individuals with skin intact (there are also other fossilized skin impressions of these dinosaurs).

The hadrosaruids were large ornithopods, with lengths of 7 to 10 meters. They had broad, toothless beaks and intricate dental batteries. The dental batteries consisted of hundreds of teeth with a washboard-like grinding surface and three replacement teeth in each tooth position. As in the hyspsilophodontids, they had kinetic jaws such that the upper jaw moved outward and the lower jaw moved inward during chewing. They could process fibrous vegetation, even twigs.

Two mummified hadrosaurids from Canada have stomachs full of conifer needles and twigs, seeds, and other tough plant material. There is very little variation among hadrosaurid skelet

ons, so identification is based on skull structure. There are two major subfamilies based on skull type, the Hadrosaurinae and the Lambeosaruinae

Hadrosaurinae

The hadrosaurines were the more primitive subfamily with rather flat skull roofs or solid crests on the skull. They were large "Roman-nosed" hadrosaurids with long nasals, which often peaked near the posterior end of the nostrils. Examples are Edmontosaurus and Maisauria.

Lambeosaurinae

These were the "crested" duck-bills. They are distinguished by convoluted tubes and crests on the tops of their skulls. The crests contained modified nasal passages and a nasal cavity that was relocated to a position above the orbits. The crests and tubes changed during the growth of individuals, suggesting that sexual dimorphism may have been present. The Upper Cretaceous genera Parasaurolophus and Corythosaurus are representative examples of lambeosaurines.

Short Description

• Like iguanodontids, hadrosaurids were large, strong, quadrapedal walkers, but also could walk on two legs.


• Mummies from Alberta have flaps of skin between fingers, has been suggested that they may have had webbed hands; however, the shrunk and stretched skin from mummification may only make it appear that way.


• They had a tall, paddle-like tail, perhaps for propelling in water.


• Their skeletons are found in river, lake, swamp, deltaic, and sea depositis. Perhaps they were aquatic dinosaurs. But hadrosaurids were also well suited to living on dry land and thus may have entered the water only for feeding or for defensive purposes.


• Had a very wide geographic distribution, known from North America, Asia, Europe, and South America. But they were most abundant and diverse in Asia and North America.


• The hadrosaurids were the dominant plant eating dinosaurs of the Late Cretaceous and they were among the last dinosaurs to become extinct.

HYPSILOPHODONTIDAE

The hysilophodontidae are the most primitive members of Euornithopoda and are a sister group within this clade to Iguandontia (which encompasses all more derivied euornithopods, including the Iguanodontidae and the Hadrosauridae [duck bills]).

Facts

• The hypsilophodontidae were small (2 to 4 meters), bipedal ornithischians that are known from Middle Jurassic to Upper Jurassic rocks of North America, Europe, Asia, and Australia The best known genus is Hypsilophodon


• Bipedal runner, hind limbs much longer than forelimbs.


• Ankle elongate.


• Long tail - stiffened by ossified tendons.


• Skull resembles that of Heterodontasaurus, but does not have the large canine teeth.


• Large eyes.


• Massive jaws, dental battery of interlocking cheek teeth that wore-down to produce a continuous, inclined cutting edge.


• A joint in the skull allowed the upper jaw to move outward over the lower jaw when chewing (a dynamic skull feature).

Hypsilophodonts are well known from complete skeletons and eggs. They were first known from the Middle Jurassic of China, but reached their peak diversity during Late Jurassic to Early Cretaceous. However, they did range to Late Cretaceous.

Two euornithopods that are very similar to the hypsilophodontids, and that may be very close to the evolutionary ancestral stock that links the hypsilophodontids to the iguanodontids, are Tenontosaurus (Lower Cretaceous of North America) and Dryosaurus (Upper Jurassic of North America and Africa).

Both lack premaxillary teeth and had other characters midway between the two groups (Lucas, 1997). However, some prefer to place these two dinosaurs as primitive members of Iguanodontia (which includes all more derived euornithopods above the hpsilophodontidae).

Iguanodon

Iguanodon is best known from Lower Cretaceous rocks of Bernissart, Belgium (where 31 adult skeletons were found in a coal mine at a depth of 321 meters). It is much larger and more specialized than Camptosaurus

Iguanodon had the following characteristics

• Had very long forelimbs (70 to 80% as long as hind limbs).

• The wrist bones were fused (for stable hand walking).

• Central 3 digits of the hand ended in hooves.

• Large conical thumb spike (perhaps a defensive weapon).

• Extensive boxwork of ossified tendons extending along the back vertebrae from the shoulder region to the middle of the tail.

Iguanodon probably did more quadrapedal walking than Camptosaurus or other small ornithopods. But could probably rear up on hind legs and swing its spike-like thumb for defense.

Description of Iguanodontids

• Iguanodontid snouts were long with many more teeth than in heterodontosaurids or hypsilophodontids.

• The beaks were used to crop vegetation.

• Teeth leaf-shaped with long ridges on their sides and small cusps on the cutting edges (resembling teeth of the living iguanas - thus the name for the family).

• Camptosaurus is the oldest iguanodontid and is best known from Upper Jurassic rocks of North America and Europe.

• The zenith of iguanodontid diversity occurred in Early to Medial Cretaceous time in Europe, North America, Africa, Asia, and Australia.

• Iguanodon, Lower Cretaceous of Europe, is the most typical representative of the Iguanodontidae and is the best known genus (with several complete skeletons known).

• A particularly unusual Lower Cretaceous iguanodontid is Ouranosaurus from Niger, Africa, which had a very distinctive head and long neural spines along the back (see page 212 in Fastovsky and Weishampel, 1996).

• There was a marked decline of iguanodontids in Late Cretaceous due (probably) to the appearance of the hadrosaurids (duck-bills).

Eoraptor dinosaur

The Eoraptor lunensis, a medium-sized carnivore found in the Ischigualasto Formation of northwestern Argentina. The find occurs alongside other early dinosaurs and their kin, such as Herrerasaurus and Pisanosaurus.

Eoraptor lacks the specialized features of any of the major groups of dinosaurs, and is quite similar to what would be expected for dinosaur ancestors. This has led some to conclude that it is not part of the dinosaurs proper, but is a closely related archosaur. Others have pointed to the functionally three-fingered hand as an indication of close ties to theropod dinosaurs.

In any case, the traits of Eoraptor suggest that the first dinosaurs were small, bipedal predators. Taken together, the finds at Ischigualasto demonstrate that dinosaurs had radiated by the Late Triassic.

Eoraptor lunensis is roughly the same age as Herrerasaurus - 232 million years old - yet it already shows specialized features which indicate that it lies several branches up from the base of the dinosaurian family tree.

The exact nature of these features suggest that Eoraptor lies at the base of the great Theropoda lineage - the theropod dinosaurs - which includes many celebrity species, such as Tyrannosaurus rex, Allosaurus, Deinonychus, and Velociraptor. .

The upper Triassic Eoraptor is one of the earliest dinosaurs, close to the common dinosaur ancestor. Sereno considers it a primitive theropod, although others consider it a primitive dinosaur or pre-dinosaur.

Attractive features

Foundation- Patagonia, Argentina, South America

Analysis- It had light, hollow bones, a long head with dozens of small, sharp teeth, and five fingers on its hands (two of the fingers on each hand were very small)

Length-1 meter

Height and weight – mass

Locomotion-Bipedal

Food-carnivore

Time period-228 million years

Dinosaur group-Theropod

Dilong paradoxus

Dilong paradoxus-emperor dragon is a primitive, emu-sized tyrannosaur which was covered in feathers. When it lived 130 million years ago.

Description

Dilong paradoxus had a covering of simple feathers or protofeathers. The feathers were seen in fossilized skin impressions from near the jaw and tail. It possessed three fingers on its hands. Growth ring studies indicate that tyrannosaurs grew very quickly when young, supporting warm-bloodedness Dilong paradoxus is a small tyrannosauroid estimated to be 1.6m in body length. The small size of Dilong paradoxus, in comparison with more derived, large tyrannosauroids, Dilong paradoxus shares numerous derived cranial similarities with other tyrannosauroids .

Dilong paradoxus has a less robust skull, a much larger external naris, an expanded braincase, a lower sagittal crest, and anteroposteriorly longer basicranium and a smaller mylohyoid foramen,and lacks a surangular foramen (Fig. 1a–e). Some of these features might be size related; however, progressively larger size is a phylogenetic trend in tyrannosaurids7,9,11. It is also different from other tyrannosauroids in several unique features.

• Discovered country: china

• Eatable-carnivorous

• Weight-73lb

• Length-5.1 feet

Unaysaurus dinosaurs

• It is the oldest dinosaurs known.

• It was discovered in southern Brazil in the geopark of paleorrota, in 1998.


• It is the first meat eating dinosaurs present in South America before 230-250 millions.


• These are the small theropods divided into prosauropods.


• This dinosaur was strongly connected to Plateosaurus, a slightly later (and much more famous) prosauropod of late Triassic Western Europe.


• It is small and walked on two legs.

• It is about 8 feet long.2 feet tall and weighed 200 pounds.


• The main conveyable characteristics are Small size; probably bipedal posture.


• The fossils of Unaysaurus are well conserved. It consists of complete skull, completed with a lower jaw, and partial skeleton with many bones still linked to each other in their usual positions.


• It is one of the most completed dinosaur skeletons, and the most complete skull, ever improved in Brazil.

Allosaurus Dinosaurs

_The carnivorous dinosaur Allosaurus has been known since the late 1800s. This theropod was first documented in 1869.

• Allosaurus fragilis meaning "fragile, different reptile" lived approximately 145-150 million years ago during the Late Jurassic Period, with a recorded geographic range in Wyoming, Montana, Colorado, New Mexico, South Dakota, Utah, Oklahoma and Portugal (Glut, 1997; Prez-Moreno and Chure, 1999).

• It is known to reach 12 meters in length, 4.5 meters in height, and may have weighed up to 2 tons as an adult.

• A fragilis was one of the top predators of its time and is found primarily in the Morrison Formation.

• It lived on the lowland floodplains of the Western Interior in an environment similar to some of the large plains of Africa today (Russell, 1989).

• Allosaurus was the most common large carnivore of the Late Jurassic in North America.

• Strong forelimbs with sharp claws, powerful hind legs and recurved, dagger-like teeth are evidence that Allosaurus was a formidable predator.

• During the Late Jurassic, herds of plant-eating sauropods (such as Apatosaurus) were constantly on the move in search of food to satisfy their large appetites.

• Predators, such as Allosaurus, may have followed these herds, preying on the young and weak.

• Although it was much smaller than the sauropods, quite possibly Allosaurus hunted in packs to bring down larger prey. Like many meat eaters, it may also have been a scavenger.

Balaur (Romanian for "dragon")

Stocky dragon’ roamed Europe'.

It is a specialized species of carnivorous. The fossils are found an off-shore part of the European archipelago called Hațeg Island.

Description

The bones were smaller and weighted than those dromaeosaurs .The feet of the dromaeosaurs single, large. It also possesses a great number of additional autapomorphies, including a reduced and presumably nonfunctional third manual digit. It is one of the apex predators in its island ecosystem. Because there are no larger teeth found in Romania. It uses double sickle claws for slashing prey. However, the hunting behaviors as well as its typical prey are not known.

Habitat: Eastern Europe

Lived: 70-65 million years ago

Size and Weight: 2 feet long and 25 pounds

Diet: Meat

Camptosaurus

The ornithischian dinosaurs during the Cretaceous evolved into a number of interesting groups. From bipedal ornithischians during the Jurassic, like Camptosaurus, the larger and more nimble ornithopods of the Cretaceous evolved. One of the first dinosaurs to be scientifically described was Iguanodon, a bipedal herbivore thought to have moved about in herds. Iguanodon was between 6 and 10 meters long and weighed around 5 tons.

• The Camptosaurus-meaning bent lizard- Lived during the Jurassic era about 150 million years ago.


• It was medium-sized as far as dinosaurs go, weighing about 1,200 pounds and measuring about 23 feet long from head to tail.


• Its head was elongated with tightly-packed blunt teeth in the back of its jaw-evidence of a plant eater.


• In the family Camptosauridae, the toes and fingers ended with small hooflike claws.


• Some had the beginnings of the spiked thumbs that became better developed in the iguanodontids.


• Their teeth were densely packed. Camptosaurus, “bent lizard”, possessed a sharp, horny, toothless beak.


• Camptosaurus had cheeks much like humans. That is they could hold foodstuff in their mouths and chew it like other herbivores-plant eating.


• The Camptosaurus lived in bulky forests secure to rivers. It possibly lived in herds and this would have given it guard from their main meat eating predators, such as the Allosaurus.


• Camptosaurus fossils have been discovered in western North America, Europe, and Australia.


• A complete skeleton was excavated from Dinosaur National Monument in Utah, and fossil evidence of the dinosaur has also been found in Cañon City.

INTERESTING AND IMPORTANT FACT

The dinosaurs was first described by O.C marsh in 1879, but called the dinosaur a Camptonotus. Later the name was changed to Camptosaurus in 1885.

Sauropoda Dinosaur

Sauropoda is among the most diverse and widespread dinosaur lineages, having attained a near-global distribution by the Middle Jurassic that was built on throughout the Cretaceous. These gigantic herbivores are characterized by numerous skeletal specializations that accrued over a 140 million-year history. This fascinating evolutionary history has fuelled interest for more than a century, yet aspects of sauropod interrelationships remain unresolved.

Sauropods were the largest terrestrial vertebrates –their estimated body mass exceeds that of other large dinosaurs by an order of magnitude. Despite the potential biomechanical constraints at this extreme body size, sauropods were the dominant mega herbivorous group throughout 140 million years of the Mesozoic, constituting approximately one-fourth of known dinosaur genera

Description

Sauropods have a distinct, easily recognizable morphology: a long, slender neck and tail at either end of a large body supported by four columnar limbs. The anatomical details of this architecture are unique to sauropods and have furnished the basic evidence of their monophyly

Size

The most central feature was their size. Even the dwarf sauropods like Europasaurus (perhaps 5 to 6 metres) were counted among the biggest animals in their ecosystem. Their only real competitors in terms of size are the Blue Whale. But, sauropods were mainly land-based animals.

Diet

Sauropods were herbivorous (plant-eating)