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Sunday, February 7, 2010

Triceratops!

Triceratops (pronounced /traɪˈsɛrətɒps/ trye-SER-ə-tops) is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago (Mya) in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Tertiary extinction event. Bearing a large bony frill and three horns on its large four-legged body, and conjuring similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs. Although it shared the landscape with and was preyed upon by the fearsome Tyrannosaurus.


Individual Triceratops are estimated to have reached about 7.9 to 9.0 m (26.0–29.5 ft) in length, 2.9 to 3.0 m (9.5–9.8 ft) in height, and 6.1–12.0 tonnes (13,000–26,000 lb) in weight.[9] The most distinctive feature is their large skull, among the largest of all land animals. It could grow to be over 2 m (7 ft) in length, and could reach almost a third of the length of the entire animal. It bore a single horn on the snout, above the nostrils, and a pair of horns approximately 1 m (3 ft) long, with one above each eye. To the rear of the skull was a relatively short, bony frill. Most other ceratopsids had large fenestrae in their frills, while those of Triceratops were noticeably solid.


Triceratops is the best known genus of the Ceratopsidae, a family of large North American horned dinosaurs. The exact location of Triceratops among the ceratopsians has been debated over the years. Confusion stemmed mainly from the combination of short, solid frills (similar to that of Centrosaurinae), and the long brow horns (more akin to Ceratopsinae, also known as Chasmosaurinae). In the first overview of horned dinosaurs, R. S. Lull hypothesized two lineages, one of Monoclonius and Centrosaurus leading to Triceratops, the other with Ceratops and Torosaurus, making Triceratops a centrosaurine as the group is understood today. Later revisions supported this view, formally describing the first, short-frilled group as Centrosaurinae (including Triceratops), and the second, long-frilled group as Chasmosaurinae.

Saturday, February 6, 2010

Troodon (Stenonychosaurus)!

Troodon (or Troödon in older sources) is a genus of relatively small, bird-like dinosaur from the Late Cretaceous period (75-65 mya). Discovered in 1855, it was among the first dinosaurs found in North America.

Its name (pronounced /ˈtroʊ.ɵdɒn/ TROE-o-don) is Greek for "wounding tooth", referring to the dinosaur's teeth, which are different from those of most other theropods. The teeth bear prominent, apically oriented serrations. These "wounding" serrations, however, are morphometrically more similar to those of herbivorous reptiles, and suggest a possibly omnivorous diet.


 Troodon was a small dinosaur, around 2 metres (6.6 ft) in length, 1 metre (3.3 ft) tall, and weighed about 27 to 45 kilograms (60 to 99 lb). It had very long, slender limbs, suggesting that the animal was able to move quickly. It had long 'arms' that folded against the wall of the thorax like a bird's. It had large, retractable sickle-shaped claws on its second toes, which were raised off the ground when running.

 

The first specimen of Troodon that was not a tooth, then referred to its own genus (Stenonychosaurus), was named by Sternberg in 1932, based on a foot, fragments of a hand, and some caudal vertebrae from Alberta. A remarkable feature of these remains was the enlarged claw on the second toe, which is now recognized as characteristic of Deinonychosauria. Sternberg initially classified Stenonychosaurus as a member of the family Coeluridae. Later, Sternberg (1951) speculated that since Stenonychosaurus had a "very peculiar pes" and Troodon "equally unusual teeth", they may be closely related. Unfortunately, no comparable specimens were available at that time to test the idea.


Stenonychosaurus has been credited with being the most intelligent dinosaur. Compared with most others, it had a relatively large brain, although the excess brain volume was probably not concerned with reasoning and other activities that could be called "intelligence." 

Thursday, February 4, 2010

Compsognathus!

Compsognathus (Greek kompsos/κομψος; "elegant", "refined" or "dainty", and gnathos/γναθος; "jaw") was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Today, C. longipes is the only recognized species, although the larger specimen discovered in France in the 1970s was once thought to belong to a separate species, C. corallestris.


Many presentations still describe Compsognathus as a "chicken-sized" dinosaur because of the small size of the German specimen, which is now believed to be a juvenile form of the larger French specimen. Compsognathus is one of the few dinosaurs for which the diet is known with certainty: the remains of small, agile lizards are preserved in the bellies of both specimens. Teeth discovered in Portugal may be further fossil remains of the genus.


For decades, Compsognathus was famed as the smallest dinosaur known; the specimens collected were around 1 meter (3 ft) in length. However, dinosaurs discovered later, such as Caenagnathasia, Microraptor and Parvicursor, were even smaller. The largest Compsognathus specimen is estimated to have weighed somewhere between 0.83 and 3.5 kg (between 1.8 and 7.7 lb).

Giganotosaurus carolinii!

Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived around 97 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It is one of the largest known terrestrial carnivores, slightly larger than Tyrannosaurus, but smaller than Spinosaurus. Its fossils have been found in Argentina.


Giganotosaurus carolinii was slightly larger than Tyrannosaurus rex, but had a brain only about half as big as those of tyrannosaurids. The teeth of Tyrannosaurus were longer and wider, and more variable in size. The teeth of Giganotosaurus were shorter, less variable and narrower than those of Tyrannosaurus, and were more adapted for slicing flesh. A well-developed olfactory region means that it probably had a good sense of smell. Its skull, although large, had a slender build.


Giganotosaurus, along with relatives like Tyrannotitan, Mapusaurus and Carcharodontosaurus, are members of the carnosaur family Carcharodontosauridae. Both Giganotosaurus and Mapusaurus have been placed in their own subfamily Giganotosaurinae by Coria and Currie in 2006 as more carcharodontosaurid dinosaurs are found and described, allowing interrelationships to be calculated.
 Length: 42 feet (13 meters)
Weight: Estimated 8 tons (7,300 kg)
Diet: Meat
Range: South America (Argentina)
Age: Early Late Cretaceous, 100-90 million years ago

Wednesday, February 3, 2010

Stegosaurus!

Stegosaurus is a genus of stegosaurid armored dinosaur from the Late Jurassic period (late Kimmeridgian to Early Tithonian) in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well.[1] Due to its distinctive tail spikes and plates, Stegosaurus is one of the most recognizable dinosaurs, along with Tyrannosaurus, Triceratops, and Apatosaurus. The name Stegosaurus means "roof-lizard" and is derived from the Greek στέγος-, stegos- ("roof") and σαῦρος, -sauros ("lizard").

 

They lived some 150 to 145 million years ago, in an environment and time dominated by the giant sauropods Diplodocus, Camarasaurus, and Apatosaurus.

A large, heavily built, herbivorous quadruped, Stegosaurus had a distinctive and unusual posture, with a heavily arched back, short forelimbs, head held low to the ground and a stiffened tail held high in the air. Its array of plates and spikes has been the subject of much speculation. The spikes were most likely used for defense, while the plates have also been proposed as a defensive mechanism, as well as having display and thermoregulatory (heat control) functions. Stegosaurus was the largest of all the stegosaurians (bigger than genera such as Kentrosaurus and Huayangosaurus) and, although roughly bus-sized, it nonetheless shared many anatomical features (including the tail spines and plates) with the other stegosaurian genera.


Averaging around 9 meters (30 ft) long and 4 meters (14 ft) tall, the quadrupedal Stegosaurus is one of the most easily identifiable dinosaurs, due to the distinctive double row of kite-shaped plates rising vertically along its arched back and the two pairs of long spikes extending horizontally near the end of its tail. Although a large animal, it was dwarfed by its contemporaries the giant sauropods. Some form of armor appears to have been necessary, as it coexisted with large predatory theropod dinosaurs, such as the fearsome Allosaurus and Ceratosaurus.

 


Brachiosaurus!

Brachiosaurus, meaning "arm lizard", from the Greek brachion/βραχιων meaning "arm" and sauros/σαυρος meaning "lizard", was a genus of sauropod dinosaur that lived during the Late Jurassic Period and possibly the Early Cretaceous Period. It was named thus because its forelimbs were longer than its hind limbs. One of the largest animals known to have walked the earth.

 

For many decades, Brachiosaurus was among the largest dinosaur known, especially when complete specimens (now classified as Giraffatitan) were attributed to it. However, a study comparing Brachiosaurus and Giraffatitan by Michael Taylor in 2009 found that the true Brachiosaurus specimens from North America actually represent a heavier, likely longer individual. In fact, the most complete and largest specimens of Brachiosaurus come from a sub-adult individual, so it likely would have grown larger than even current size estimates.

 

Based on measurements of comparable bones, Brachiosaurus was similar in overall size to the related Giraffatitan, which is estimated to have attained 25 metres (82 ft) in length and was probably able to raise its head about 13 metres (43 ft) above ground level. However, Brachiosaurus may have been longer, as it had a longer torso and possibly a longer tail than Giraffatitan. No neck material is known from the holotype specimen; however, there are some brachiosaur neck vertebra that have been assigned to Brachiosaurus by some authors. If the vertebrae do belong to Brachiosaurus then they suggest that it had a similarly proportioned neck to Giraffatitan. Additionally, the best known Brachiosaurus specimen was not fully grown when it died, meaning it may have had an adult length of over 25 m. Brachiosaurus was also stockier, and therefore likely heavier, than Giraffatitan. Brachiosaurus is estimated to have weighed 28.7 tonnes (28.2 LT; 31.6 ST), compared to 23.3 tonnes (22.9 LT; 25.7 ST) for Giraffatitan.

Tuesday, February 2, 2010

Dinosaur!

Any of a group (sometimes considered as two separate orders) of extinct reptiles living between 205 million and 65 million years ago. Their closest living relations are crocodiles and birds. Many species of dinosaur evolved during the millions of years they were the dominant large land animals. Most were large (up to 27 m/90 ft), but some were as small as chickens. They disappeared 65 million years ago for reasons not fully understood, although many theories exist, perhaps the most widely accepted being that the Earth was struck by a comet.




Classification

 
Dinosaurs are divisible into two unrelated stocks, the orders Saurischia (‘lizard-hip’) and Ornithischia (‘bird-hip’). Members of the former group possess a reptile-like pelvis and are mostly bipedal and carnivorous, although some are giant amphibious quadrupedal herbivores. Members of the latter group have a bird-like pelvis, are mainly four-legged, and entirely herbivorous.

The Saurischia are divided into: theropods (‘beast-feet’), including all the bipedal carnivorous forms with long hindlimbs and short forelimbs (tyrannosaurus, megalosaurus); and sauropodomorphs (‘lizard-feet forms’), including sauropods, the large quadrupedal herbivorous and amphibious types with massive limbs, long tails and necks, and tiny skulls (diplodocus, brontosaurus).

The Ornithischia were almost all plant-eaters, and eventually outnumbered the Saurischia. They are divided into four suborders: ornithopods (‘bird-feet’), Jurassic and Cretaceous bipedal forms (iguanodon) and Cretaceous hadrosaurs with duckbills; stegosaurs (‘plated’ dinosaurs), Jurassic quadrupedal dinosaurs with a double row of triangular plates along the back and spikes on the tail (stegosaurus); ankylosaurs (‘armoured’ dinosaurs), Cretaceous quadrupedal forms, heavily armoured with bony plates (nodosaurus); and ceratopsians (‘horned’ dinosaurs), Upper Cretaceous quadrupedal horned dinosaurs with very large skulls bearing a neck frill and large horns (triceratops).

Interesting facts
Brachiosaurus, a long-necked plant-eater of the sauropod group, was about 12.6 m/40 ft to the top of its head, and weighed 80 tonnes. Compsognathus, a meat-eater, was only the size of a chicken, and ran on its hind legs. Stegosaurus, an armoured plant-eater 6 m/20 ft long, had a brain only about 3 cm/1.25 in long. Not all dinosaurs had small brains. At the other extreme, the hunting dinosaur stenonychosaurus, 2 m/6 ft long, had a brain size comparable to that of a mammal or bird of today, stereoscopic vision, and grasping hands. Many dinosaurs appear to have been equipped for a high level of activity. Tyrannosaurus was a huge, two-footed, meat-eating theropod dinosaur of the Upper Cretaceous in North America and Asia. The largest carnivorous dinosaur was Giganotosaurus carolinii. It lived in Patagonia about 97 million years ago, was 12.5 m/41 ft long, and weighed 6–8 tonnes. Its skeleton was discovered in 1995.

Monday, February 1, 2010

Allosaurus

Allosaurus (pronounced /ˌælɵˈsɔrəs/) is a genus of large theropod dinosaur that lived 155 to 145 million years ago, in the late Jurassic period (Kimmeridgian to Tithonian). The name Allosaurus means "different lizard" and is derived from the Greek αλλος/allos ("different, strange") and σαυρος/sauros ("lizard").

 
 

Allosaurus was a large bipedal predator with a large skull, equipped with dozens of large, sharp teeth. It averaged 8.5 meters (28 ft) in length, though fragmentary remains suggest it could have reached over 12 meters (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long, heavy tail.

 

The different species of Allosaurus varied in weight. Allosaurus fragilis, A. atrox, and A. ferox weighed about 1.1 to 1.9 tons (1 tonne to 1.7 tonnes); A. amplexus was much heavier and weighed about 2.7 to 5.5 tons (3 tonnes to 5 tonnes).


Look at this beautiful video from Walking with Dinosaurs - Diplodocus Hunting (allosaurs in action)

Sunday, January 31, 2010

Diplodocus

Diplodocus is a genus of diplodocid sauropod dinosaur whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a Neo-Latin term derived from Greek διπλόος (diploos) "double" and δοκός (dokos) "beam", in reference to its double-beamed chevron bones located in the underside of the tail.
 
Diplodocus was a long-necked, whip-tailed giant, measuring about 90 feet (27 m) long with a 26 foot (8 m) long neck and a 45 foot (14 m) long tail, but its head was less than 2 feet long. It was among the longest land animals ever. Its nostrils were at the top of its head and it had peg-like teeth, but only in the front of the jaws. Its front legs were shorter than its back legs, and all had elephant-like, five-toed feet. One toe on each foot had a thumb claw, probably for protection. A fossilized Diplodocus skin impression reveals that it had a row of spines running down its back.



Here is the amazing reproduction of diplodocus. This is the part from the ballad: Walking with Dinosaurs

Friday, January 29, 2010

Tyrannosaurus (T. Rex)

Tyrannosaurus (meaning 'tyrant lizard') from the Greek words τυραννος (tyrannos, meaning "tyrant") and σαυρος (sauros, meaning "lizard") , was a genus of theropod dinosaur. The species Tyrannosaurus rex ('rex' meaning 'king' in Latin), commonly abbreviated to T. rex, is a fixture in popular culture.
It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the last three million years of the Cretaceous Period, approximately 68 to 65 million years ago.
Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits.
Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it was the largest known tyrannosaurid and one of the largest known land predators, measuring up to 13 metres (43 ft) in length, up to 4 metres (13 ft) tall at the hips, and up to 6.8 metric tons (7.5 short tons) in weight.

Pythons

The Pythonidae, commonly known simply as pythons, are a family of non-venomous snakes found in Africa, Asia and Australia. Among its members are some of the largest snakes in the world. Eight genera and 26 species are currently recognized.
Pythons range from 1 to 10 m (3 to 33 ft) long and weigh up to 140 kg (300 lb). The female lays 15 to 100 eggs, and broods them until they hatch.
Most members of this family are ambush predators, in that they typically remain motionless in a camouflaged position and then strike suddenly at passing prey. They will generally not attack humans unless startled or provoked, although females protecting their eggs can be aggressive. Large adult specimens can kill people.
Prey is killed by a process known as constriction; after an animal has been grasped to restrain it, a number of coils are hastily wrapped around it. Then, by applying and maintaining sufficient pressure to prevent it from inhaling, the prey eventually succumbs due to asphyxiation.

Wednesday, January 27, 2010

Black Mamba

Mambas, of the genus Dendroaspis, are fast-moving land-dwelling snakes of Africa. ("Dendroaspis" is literally "tree snake".) They belong to the family of Elapidae which includes cobras, coral snakes, kraits and, debatably, sea snakes although these are now classed as Hydrophiidae, all of which can be highly deadly.

The black mamba (D. polylepis) is the longest venomous snake in Africa, with a potent neurotoxic venom that attacks the nervous system, and cardiotoxins which attack the heart; the bite is often fatal to humans without access to proper first aid and subsequent antivenom treatment, because it shuts down the lungs and heart.
In contrast to all other species in this genus, which are arboreal, black mambas reside in hollow insect mounds, abandoned burrows, and rock crevices. They are diurnal. During the day they actively hunt their prey of small mammals, birds and lizards. They return to the same lair nightly.
Mambas are related to the cobras (Elapidae), as can be seen during their threat display, when they stretch a slightly smaller 'hood' while gaping their mouth. Unlike most other snakes, mambas will strike repeatedly if cornered, and have been reported to bring down a giraffe and a lion with their venom.