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.

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." 

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

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.

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.

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)