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.

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.

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.

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.


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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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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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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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).

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.

Scientific Classification

Kingdom : Animalia

Phylum : Chordata

Class : Sauropsida

Superorder : Dinosauria

Order : Saurischia

Suborder : Sauropodomorpha

Infraorder : Sauropoda

Superfamily : Diplodocoidea

Family : Rebbachisauridae

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