Sunday, March 27, 2011

Dinosaur with distinctive cranial crown

Lambeosaurus a hadrosaurid dinosaur lived about 76 to 75 million years ago during the Late Cretaceous Period in the region of North America. This bipedal or quadrupedal, plant-eating dinosaur was recognized for its unique concave cranial crest It is about 15 meters long. The Mexican species L. laticaudus was considered to be one of the highest ornithischians.


Lambeosaurus
Lambeosaurus was tardily described by William Parks in 1923.Twenty years later the first matter was premeditated by Lawrence Lambe. The genus had a difficult taxonomic record since small-bodied cranial hadrosaurid were recognized as infantile and thought to belong to own genera and species. At present, a variety of skulls are allocated to the type species L. lambei and the interpretation shows the age differences and sexual dimorphism between the skulls.

Lambeosaurus directly relates to a species name Corythosaurus, which is found vaguely in older rocks. All had strange crests, which are served for some social functions like noisemaking and identification. Lambeosaurus was pretty parallel to the famous Corythosaurus in everything except in the form of the head decoration. In comparison with Corythosaurus, the crown of Lambeosaurus was moved ahead, and the concave nasal passages are at the front of the crest and stacked vertically.

Lambeosaurus move on two legs as well as with four which is exposed by footprints of related animals. It had an elongated tail stiffened by hardened tendons that is used to prevent it from sagging. The hands consist of four fingers lacking the innermost one of the comprehensive five-fingered tetrapod hand. The second, third, and fourth fingers were clustered together with weary hooves suggesting that the animal could use the hands for sustain. The fifth finger was liberated and used to work on some objects. Each foot of Lambeosaurus had only three central toes.


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Friday, March 25, 2011

Fossilized footpath of dinosaur

The collection of dinosaur footprints varies from few inches to around few feet across and the biggest footprints belonged to the huge long necked and tailed plant-eating dinosaur called sauropods.The theropods which are the meat-eating dinosaurs comprised of three-toed feet.The feet of plant-eating dinosaurs vary from meat-eating dinosaurs.

Dinosaur footprints usually made in sludge or fine sand have been found over 1500 places including quarries, coal mines, riverbeds, deserts, and mountains.There are many fossils found as each dinosaur made many tracks it can fossilize well.Moreover relating a set of tracks with a particular genus is normally impossible.


Real foot prints
The subsequent are the information about fossil footprints,
Speed
Length of stride,
The bone structure of the foot,
Irritating behavior the existence of herds,
Whether they walked on two or four legs and how their tail was carried.

Dinosaur footprints are extremely rich in many areas, and provide prosperous sources of scientific information on dinosaur behavior, locomotion, foot anatomy, ecology, chronology, and geographic distributions.The extensive revival of significance in dinosaurs has been liked by a new interest in dinosaur tracks.

Today countless professional "trackers" are vigorously studying about the footprints of dinosaur all around the world. For ruling, documenting, and interpreting dinosaur footpaths include tackle and techniques which varies from those applied to corpse fossils. A number of admirable dinosaur footpaths are now available to the public.

Theropod track
Some footpaths are so fresh- looking which is hard to imagine that the track-walkers having stridden by only moments before.Until the desire of cloning dinosaurs becomes a reality, this is probably the closest one we can come to stand beside a breathing dinosaur.

Monday, March 21, 2011

Running Lizard

The Dromaeosaurus which had remarkably large eyes and excellent vision resembles the Velociraptor, lived during the Late Cretaceous period.

The name means 'running lizard' and is derived from the Greek dromeus meaning 'runner' and sauros meaning 'lizard'.

Dromaeosaurus was a small carnivore, the size of a wolf, about 2 m in length and 15 kg in weight. Its mouth was full of sharp teeth, and it had a sharp "sickle claw" on each foot.

It lived during the Campanian stage of the Late Cretaceous, however, some fragmentary remains such as teeth which may belong to this genus have been found from the late Maastrichtian age Lance and Hell Creek Formations, dating to 65.5 million years ago.

Although only a few bones are known from the hind limb, they indicate that Dromaeosaurus was a powerfully built animal.

The presence of feathers in closely related animals makes it extremely likely that it was feathered as well.

It also probably had a good sense of smell and hearing. Its neck was curved and flexible and its jaws were solidly built.

Dromaeosaurus
The tail was flexible at the base but sheathed in a lattice of bony rods; this allowed it to be carried in a sharply upturned position.

In Dromaeosaurus albertensis, the vena capitis dorsalis "drains the anterior neck muscles through a pair of long canals on the posterior surface of the endocast."

Despite receiving widespread attention in popular books on dinosaurs, and the usage of a complete mounted skeleton cast in museums throughout the world, Dromaeosaurus is surprisingly poorly known from actual fossils.

The first known Dromaeosaurus remains were discovered by paleontologist Barnum Brown during a 1914 expedition to Red Deer River on behalf of the American Museum of Natural History.

The area where these bones were collected is now part of Dinosaur Provincial Park in Alberta; Canada.

The find consisted of a partial skull 24 cm in length, and some foot bones. Several other skull fragments, and about 30 isolated teeth, are known from subsequent discoveries in Alberta and Montana.

Several species of Dromaeosaurus have been described, but Dromaeosaurus albertensis is the most complete specimen.


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Tuesday, March 15, 2011

Respiratory System of Dinosaurs

Air Sacs

As we all know that the birds' lungs obtain air during the respiratory process (during both the inhalation as well as exhalation process).The air sacs do all the "pumping" and the lungs simply absorb oxygen.

Since 1870 onwards scientists have generally accepted that the post-cranial skeletons of many dinosaurs contained many air-filled cavities especially in the vertebrae. Pneumatization of the skull is found in both synapsids and archosaursu, but postcranial pneumatization is found only in birds, non-avian saurischian dinosaurs, and pterosaurs.

For a long time these cavities were regarded simply as weight-saving devices, but Bakker proposed that they contained air sacs like those that make birds' respiratory systems the most efficient of all animals.

John Ruben et al. (1997, 1999, 2003, 2004) disputed this and suggested that dinosaurs had a "tidal" respiratory system (in and out) powered by a crocodile-like hepatic piston mechanism - muscles attached mainly to the pubis pull the liver backwards, which makes the lungs expand to inhale; when these muscles relax, the lungs return to their previous size and shape, and the animal exhales. They also presented this as a reason for doubting that birds descended from dinosaurs.

Researchers have presented evidence and arguments for air sacs in sauropods, "prosauropods", coelurosaurs, ceratosaurs, and the theropods Aerosteon and Coelophysis.

Three explanations have been suggested for the development of air sacs in dinosaurs:
• Increase in respiratory capacity.
• Improving balance and maneuverability by lowering the center of gravity and reducing rotational inertia.
• As a cooling mechanism. It seems that air sacs and feathers evolved at about the same time in coelurosaurs. If feathers retained heat, their owners would have required a means of dissipating excess heat. This idea is plausible but needs further empirical support.


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Sunday, March 13, 2011

Proceratosaurus

Proceratosaurus

Proceratosaurus a small sized dinosaur with fine peak on nose lived during Middle Jurassic period 175 million years ago.

It is about 9 feet long and 500 pounds.

This theropod dinosaur was carnivorous.

Its skull was first discovered in England way back in 1910.

Proceratosaurus was thought to have been related to the similarly crested Ceratosaurus, which lived much later.

Today, though, paleontologists identify this middle-Jurassic predator as more similar to small, early theropods like Coelurus and Compsognathus.

Despite its relatively small size, Proceratosaurus was one of the biggest hunters of its day, since the tyrannosaurs and other large theropods of the middle Jurassic had yet to reach their maximum sizes.

It was quite likely a very fast predator.

Its skull had a nasal horn at the front and sharply pointed recurved and serrated teeth.

The type specimen is held in the London Museum of Natural History and was recovered in 1910 at Minchinhampton while excavating for a reservoir.

Arthur Smith Woodward, who initially studied Proceratosaurus, originally thought it to be an ancestor of the Late Jurassic Ceratosaurus, due to the similarity of their nasal crests.

Later study during the 1930s by Friedrich von Huene supported this interpretation, and Huene thought both dinosaurs represented members of the group Coelurosauria.

The first major re-evaluation of Proceratosaurus and its relationships was published in 2010 by Oliver Rauhut and colleagues.

Several phylogenetic studies in the early 21st century finally found Proceratosaurus (as well as Ornitholestes) to be a coelurosaur, only distantly related to the ceratosaurids and allosauroids, though one opinion published in 2000 considered Proceratosaurus a ceratosaurid without presenting supporting evidence.


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Thursday, March 10, 2011

Austroraptor

Austroraptor the largest raptor Woodlands of South

America lived during the late Cretaceous (70 million years ago) period.

Austroraptor was a genus of dromaeosaurid dinosaur.

It is about 16 feet long and 500 pounds, large s

ize, narrow snout with short arms.

As with all types of dinosaurs, paleontologists are unearthing new raptors all the time.

One of the latest to join the flock is Austroraptor, which was "diagnosed" in 2008 based on a skeleton dug up in Argentina (hence the "austro," meaning "south," in its name).

Austroraptor


To date, Austroraptor is the largest raptor yet discovered in South America, measuring a full 16 feet from head to tail and probably weighing in the neighborhood of 500 pounds--proportions that would have given its North American cousin, Deinonychus, a run for its money, but would have made it no match for the nearly one-ton Utah-raptor that lived tens of millions of years earlier.

The fossil specimen was discovered in the Late Cretaceous deposits located in the Río Negro Province of Argentina.

The species was named in honor of Alberto Cabaza, who founded the Museo Municipal de Lamarque where the specimen was partially studied.

A cladistic analysis of the specimen's anatomical features by the describers placed Austroraptor within the subfamily Unenlagiinae of the Dromaeosauridae.

Some of these characteristics include the geometry and formation of the specimen's vertebral elements.

It was determined that Austroraptor was a close relative of the unenlagiine dromaeosaur Buitreraptor.

The dinosaur would have been slender and carnivorous.

It has a strangely elongated skull, and suggests that raptors in the southern hemisphere were both thriving and diversifying even as that family of dinosaurs was declining in the northern hemisphere.

Dinosaurs flourished during this period, but unless and until more Austroraptor fossils are discovered, it will be difficult to say much more about how this new species fit into the environment of its time.

At that time in natural history, the Patagonian region consisted of plains and rivers populated by duck-billed herbivores, which might have been Austroraptor food supply.


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Rebbachisaurus

Rebbachisaurus was a huge, diplodocus sauropod dinosaur that lived about 113 to 97.5 million years ago.

This quadrupedal plant-eater had a whip-like tail, a long neck, a small head, clawed hind legs, a high-arched back, and a bulky body. It may have had a sail on its back.

Rebbachisaurus is distinguished from other sauropods by its unusually tall, ridged back.

The discovery of Rayososaurus, a South American sauropod nearly identical to Rebbachisaurus, supports the theory that there was still a land connection between Africa and South America during the Early Cretaceous, long after it was commonly thought the two continents had separated.

Rebbachisaurus was about 68 ft (20 m) long.

The type species is R. garasbae.

Rebbachisaurus was named by Lavocat in 1954.

Fossils have been found in Morocco and Niger, Africa.


Rebbachisaurus

Scientific Classification

Kingdom : Animalia

Phylum : Chordata

Class : Sauropsida

Superorder : Dinosauria

Order : Saurischia

Suborder : Sauropodomorpha

Infraorder : Sauropoda

Superfamily : Diplodocoidea

Family : Rebbachisauridae



Monday, March 7, 2011

Oviraptor

Oviraptor is a tiny Mongolian theropod dinosaur, initially exposed by the paleontologist Roy Chapman Andrews.

It was first described by Henry Fairfield Osborn, in 1924.

Its name is Latin for 'egg thief', referring to the fact that the first fossil specimen was discovered atop a pile of what were thought to be Protoceratops eggs, and the specific name philoceratops means "lover of ceratopsians", also given as a result of this find.

In his 1924 paper, Osborn explained that the name was given due to the close proximity of the skull of Oviraptor to the nest (it was separated from the eggs by only four inches of sand).

However, Osborn also suggested that the name Oviraptor "may entirely mislead us as to its feeding habits and belie its character".

In the 1990s, the discovery of nesting oviraptorids like Citipati proved that Osborn was correct in his caution regarding the name.

These finds showed that the eggs in question probably belonged to Oviraptor itself, and that the specimen was actually brooding its eggs.

Oviraptor lived in the late Cretaceous period, during the late Campanian stage about 75 million years ago; only one definitive specimen is known (with associated eggs), from the Djadokhta Formation of Mongolia, though a possible second specimen (also with eggs) comes from the northeast region of Inner Mongolia, China, in an area called Bayan Mandahu.


Oviraptor

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Friday, March 4, 2011

Dinosaur Tail

About Dinosaur Tail

Offset– Many of the dinosaur tails are used to counterbalance a long narrow part or a weighty skull. Earlier people thought that dinosaurs dragged their tails on the ground, serving to do little but making locomotion difficult. This seemed pointless and ignored the fact that the large mass at the front of the dinosaur's body had to be counterbalanced or else the animal would tip over!

Tripod leg- The tails of some dinosaurs could be useful in attaining a support posture, which was probably used to seek very tall flora and for mate.

Help in turning quickly- Some dinosaurs needed to run quickly and to be able to turn quickly, either to catch prey or avoid predators. In order to turn quickly while running, the tail's movement can shift the runner's direction, allowing swift turns.


Euoplocephalus
Bludgeon for protection- Ankylosaurids like Euoplocephalus and Ankylosaurus had bony nodules at the end of their tails that could easily have been used for protection, which would have been useful for these clumsy, plated grazers. Also, some theropods, like Shunosaurus, Omeisaurus and maybe Mamenchisaurus had tail clubs for protection.



Mamenchisaurus

Whisk for protection- In 1961, the British zoologist R. McNeill Alexander proposed the idea that some sauropods may have used their massive tails as a whip to secure at their attackers.

Prehensile addition- Some people theorize that some dinosaur tails may have been prehensile, able to manipulate objects. The tails may have been used to build nests, move vegetation, etc., much as an elephant's trunk works.


Thursday, March 3, 2011

Soft Tissue of Dinosaur

The soft-tissue of dinosaur was revealed from its vestige in Petraroia, Italy. The discovery was reported in 1998, and described the specimen of a small, very young coelurosaur, Scipionyx samniticus.The fossil includes portions of the intestines, colon, liver, muscles, and windpipe of this immature dinosaur.

In the March 2005 issue of Science, the paleontologist Mary Higby Schweitzer and her team announced the discovery of flexible material resembling actual soft tissue inside a 68-million-year-old Tyrannosaurus rex leg bone from the Hell Creek Formation in Montana. After recovery, the tissue was rehydrated by the science team.


Blood & Connective tissue of T.rex

When the fossilized bone was treated over several weeks to remove mineral content from the fossilized bone-marrow cavity, Schweitzer found evidence of intact structures such as blood vessels, bone matrix, and connective tissue. Scrutiny under the microscope further revealed that the putative dinosaur soft tissue had retained fine structures even at the cellular level. The exact nature and composition of this material, and the implications of Schweitzer's discovery, are not yet clear; study and interpretation of the material is ongoing.

Newer research, published in PloS One, has challenged the claims that the material found is the soft tissue of Tyrannosaurus. Thomas Kaye of the University of Washington and his co-authors contend that what was really inside the tyrannosaur bone was slimy biofilm created by bacteria that coated the voids once occupied by blood vessels and cells.