nandi's blog

Gallimimus

Wednesday, November 30, 2016

Gallimimus bullatus by Kana-hebi on DeviantArt

Gallimimus (meaning “chicken mimic”) is a genus of ornithomimid theropod dinosaurs from the late Cretaceous period (Maastrichtian stage) Nemegt Formation of Mongolia. With individuals as long as 8 m (26 ft), it was one of the largest ornithomimosaurs. Gallimimus is known from multiple individuals, ranging from juvenile (about 0.5 m tall at the hip) to adult (about 2 m tall at the hip). The type species is G.bullatus, which means “capsuled chicken mimic”.
 
Reconstructed skeleton (based on the adult holotype and a juvenile specimen), Natural History Museum, London

The first fossil remains of this dinosaur were discovered in early August 1963 by a team of Professor Zofia Kielan-Jaworowska at Tsagan Khushu during a Polish-Mongolian expedition to the Gobi Desert of Mongolia. The find was reported by her in 1965. In 1972, it was named and described by paleontologists Rinchen Barsbold, Halszka Osmólska, and Ewa Roniewicz. The only named species is the type species Gallimimus bullatus. The generic name is derived from Latin gallus, “chicken”, and mimus, “mimic”, in reference to the neural arches of the front neck vertebrae which resemble those of the Galliformes. The specific name is derived from Latin bulla, a magic capsule worn by Roman youth around the neck, in reference to a bulbous swelling in the braincase on the underside of the parasphenoid, in the form of a capsule. The holotype specimen, IGM 100/11, consists of a partial skeleton including the skull and lower jaws. It is a larger skeleton; several other partial skeletons have been described, most of them of juveniles, and numerous single bones.

Human-gallimimus size comparison

A second species announced by Barsbold in 1996, “Gallimimus mongoliensis” based on specimen IGM 100/14 from the older Bayanshiree Formation, has never been formally referred to this genus. In a reanalysis of the nearly complete skeleton of “Gallimimus mongoliensis” Barsbold concluded in 2006 that it is not a species of Gallimimus but may represent a new, currently unnamed ornithomimid genus.

Gallimimus was assigned to the Ornithomimidae in 1972. This is confirmed by recent cladistic analyses.

Fabrosaurus

Wednesday, November 30, 2016

Fabrosaurus

Fabrosaurus (meaning “Fabre’s lizard” in honor of Jean Fabre, a French geologist and a colleague of Ginsburg on the expedition that collected the fossil in Basutoland, Southern Africa; Greek sauros “lizard”)) was a genus of herbivorous dinosaur which lived during the Early Jurassic (Hettangian to Sinemurian stages 199 – 189 mya).

Fabrosaurus was named by paleontologist Leonard Ginsburg in 1964 based on partial jawbone with three teeth. The type species, F. australis, was named for the location of the fossils in Lesotho, Southern Africa (australis being Latin for “southern”).

Fabrosaurus size

Subsequent discoveries included two crushed skulls and disarticulated post-cranial bones (including vertebrae, ribs, and limb bones), allowing for a more complete reconstruction. However, as additional ornithischian fossils were discovered, the features of F. australis were thought to be shared by other species, and by the 1990s and 2000s most authors working with the group found Fabrosaurus to be a nomen dubium (doubtful name), finding the holotype material described by Ginsburg to be insufficient to distinguish a new taxon. Some claim the fossils represent simple variation of Lesothosaurus, which is regarded as valid.

Ceratopsia Facts

Wednesday, November 30, 2016

Ceratopsia by Mad-Hatter-LCarol on DeviantArt

Ceratopsians are also known as ceratopians, and it means ‘horned eye’. They are very interesting dinosaurs and a lot different than the sauropods and theropods. To identify a ceratopian is not difficult because they had horns, bony frills and curved bony beaks. Ceratopians lived mainly in the Cretaceous period.

One of the most popular type of ceratopian was the Triceratops. The reason why they are called ‘horned eye’ is because they had remarkable horns above their eyes. Triceratops was the largest of this group of family and its brow horns were nearly up to a meter long.

Triceratops, one of the largest ceratopsians (a chasmosaurinae ceratopsid). It had solid frill and long horns.

Most of the ceratopians had an enormous neck frill. The frill was made of solid bone, and covered with their skin. This frill protected the ceratopians neck from being bitten or clawed by the predators. In some dinosaurs like the big Torosaurus, the bony frill grew halfway down the creature’s back. One particular dinosaur, the Psittacosaurus (parrot-lizard), did not have an obvious neck frill, but it did have another feature of the ceratopian group, which was a parrot-like beak. Experts believe this dinosaur should belong to the ceratopians, despite not having a transparent neck frill.

All ceratopians ate were herbivores and ate plants and their parrot-like beaks helped them to chop off tough plant stems. The horned eye dinosaurs included many different types of dinosaur. The group lived mainly towards the end of the Cretaceous period. Like the ornithopods, the ceratopians evolved during their time on Earth. Some of the first ceratopians, like the Protoceratops, did not have have horns, instead they had a thick, bony areas over their snouts and eyes. But eventually in time, the ceratopians developed horns. Pentaceratops was the later dinosaur to appear than Protoceratops. Pentaceratops had the most horns of all the horned dinosaurs, and its name means ‘five horned face’.

Like the rhinoceroses of today, the ceratopians walked on all four legs. The Styracosaurus had strong, muscular legs to support its massive heavy head. Its feet ended in toes which were spread out to help carry the weight of its enormous body. Another dinosaur as mentioned earlier, the Psittacosaurus, usually walked on two legs most of the time, but it may have walked on four legs in certain occasions. The ceratopians lived in North America, Europe and Asia, which are believed to be the only places where their skeleton fossils have been found so far.

Another fact about ceratopians is that some of them had holes in their frills.The neck frills were large and heavy, and to make them lighter, some of them had large holes in them to reduce the weight. Also the skin covering the bony frill stretched over the holes to make them invisible.

Ceratopsian fossil discoveries. The presence of Jurassic ceratopsians only in Asia indicates an Asian origin for the group, while the more derived ceratopsids occur only in North America save for one Asian species. Questionable remains are indicated with question marks. By Sheep81

Source: www.natgeo.com / www.wikipedia.org

Protoceratops Facts & Info

Wednesday, November 30, 2016

Protoceratops skeleton

The Discovery of the Protoceratops

The Protoceratops skeleton was first discovered by Roy Chapman Andrews. Andrews was a renowned paleontologist of the American Museum of Natural History in New York, United States. In 1922, he went on fossil-hunting expedition in Mongolia, Asia. In the Mongolian desert, he discovered fossil remains of the Protoceratops and fossilized eggs nearby. This was substantial evidence that dinosaurs laid eggs and some of them lived in family groups or herds.

Protoceratops was around the size of a large dog, so it was actually a small dinosaur. It was a herbivore and ate plants, despite the fact that it looked ferocious, with its heavy head, sharp beaked mouth and a large bony frill around its neck. The body of this small dinosaur was heavy with a long thick tail. Protoceratops walked on its four stumpy legs, and when sensed danger nearby, it was capable to move quite rapidly to escape the predators.

P. andrewsi growth series. Photo by Harry Nguyen

Facts on the Protoceratops

1. Protoceratops means ‘first horned face’
2. Its average size was about 1.8 meters long and 1 meters high
3. The average weight of the dinosaur was 400kg (900 pounds)
4. Protoceratops belonged to the group of Ceratopsians (Ceratopians)
5. It was a herbivore and ate tough leaves and plants
6. It lived around 110 – 66 million years ago in Mongolia in the Cretaceous period

The expedition in 1922 led by Roy Chapman Andrews in the Gobi Desert, in Mongolia was an extraordinary one. Even the Protoceratops’ nests which were unearthed with eggs in them were a remarkable discovery by Andrews. The discovery proved for the first time that dinosaurs laid eggs. As many as 30 eggs were found in one nest. It is unlikely that one female Protoceratops laid so many eggs at once. Experts believe that two or more females may have shared the same nest.

The skeleton fossils of Protoceratops found in Mongolia range from tiny ones still inside the eggs to small babies and fully grown adults. Some of the adults were slightly different in size because they had different shaped frills and other features may also vary. Experts think that this may be because the males were bigger with larger heads, frills and crests than the females.

Protoceratops had to guard its nests against predators such as the Oviraptor, which means ‘egg-stealer’. Dinosaur eggs would have made an ideal meal for it. A fossilized Oviraptor skeleton, with its skull smashed in, was found above a nest of Protoceratops’ eggs. Perhaps an angry mother Protoceratops had killed it when it attempted to steal the nest.

How Dinosaur Fossils Were Formed?

Wednesday, November 30, 2016

Diagram of How Dinosaur Fossils Were Formed

Was there any real proof that dinosaurs really did exist? To begin with, the fossils are the only source, clue and remains of the prehistoric animals and plants that lived millions of years ago.

Fossils were the only discovery made available to prove and gather evidence that these ancient animals really did exist. Fossils are mainly embedded in rocks which are several million years old. Generally, the hardest parts of the animals are left in the rocks such as the teeth and bones, and the flesh has eventually decayed. However, if nothing remains of an animal, there may be a hollow which the animal left behind. This hollow could be the precise shape in the rock of its body. Or it can even leave a footprint in the mud or soft sand when it was walking.

A dinosaur became a fossil after it died. The body may have fallen, or been washed into a river. The perished body may have laid on the bottom of the river floor and slowly the flesh rotted away. After that the skeleton of the dinosaur was gradually buried under the mud, and the minerals from the water seeped into the bones and preserved them. Over millions of years, the mud transformed into layers of rock and the skeleton of the dinosaur became a fossil. The sea level then dropped after millions of years later. The wind and rain then wears away the rock and that reveals the fossils which is substantial evidence that dinosaurs once lived on Earth.

Diego Pol lying by large femur thigh bone fossil of the new titanosaur find, April 2015

The experts on fossils are called paleontologists, they are known as the scientists who do all the research and the hectic detective work. Paleontologists have discovered fossils in many parts of the world. Their work can be very excruciating due to the fossils being scattered in pieces once they are found. It is very rare that paleontologists will find a whole skeleton preserved in the rock, but it is possible. They first identify the fossil bones, remove them from the ground, assemble the bones like a jigsaw, and then they determine and calculate how old the fossils are. The result of their work can be seen in natural history museums where the dinosaur skeletons are mounted and put on display for the public to view.

Besides fossil bones and teeth, which is not exactly the only clue that these animals of the past left behind, the footprints and the imprint of scaly skin, made in soft mud millions of years ago have also been found. Some of the most astounding fossils found are the droppings (or fossil feces) of the dinosaurs, and they are called coprolites. What scientists do is they grind up the dinosaur droppings, turn them into fine dust and then they find out what the dinosaurs ate to survive.

Eustreptospondylus

Saturday, November 26, 2016

Eustreptospondylus by NTamura on DeviantArt

Eustreptospondylus was a carnivorous dinosaur from the Mid-Jurassic period

A 5-7 meter long predatory dinosaur, Eustreptospondylus where one of the largest carnivores in their environment, and one of the local dinosaurs of Europe. They might have fed on small and medium sea animals, lizards, and pterosaurs that lived on the islands.

Eustreptospondylus was a theropod, a carnivorous dinosaur and a member of the Megalosauroidea superfamily, which contains relatives to the famous Megalosaurus. In WWD, Eustreptospondylus was shown to be an amphibious hunter, capable of swimming from island to island and hunt both on land and in the shadows.

Eustreptospondylus skeleton

The skull of Streptospondylus has a rather pointed snout in side view, with a large horizontally oriented nostril. There is no lacrimal horn. The skull roof is relatively thick. Oblique grooves in the jaw joints caused the gape of the mouth to be widened when the lower jaws were opened. These jaws at the front are rather tall and wide. No teeth have been preserved in either the upper or lower jaws, but the size of its toothsockets proves that the third tooth of the lower jaw was enlarged. Though not keeled, the front dorsal vertebrae have paired hypapophyses at their undersides, just as with Streptospondylus altdorfensis.

Euoplocephalus

Saturday, November 26, 2016

Euoplocephalus Tutus, digital artwork by Sergey Krasovskiy

Euoplocephalus is a dinosaur which lived approximately 70 million years ago during the late Cretaceous Period. It was first discovered by paleontologist Lawrence Morris Lambe near Red Deer River in Alberta, Canada in 1897. It was named Stereocephalus in 1902, but that name was already taken by an insect species, so it was renamed Euoplocephalus in 1910. It’s name means “well armored head.”

Size of specimen AMNH 5405 compared with a human.

The first fossil of Euoplocephalus was found in 1897 in Alberta. In 1902, it was named Stereocephalus, but that name had already been given to an insect, so it was changed in 1910. Later, many more ankylosaurid remains were found from the Campanian of North America and often made separate genera. In 1971, Walter Coombs concluded that they all belonged to Euoplocephalus which then would be one of the best-known dinosaurs. Recently however, experts have come to the opposite conclusion, limiting the authentic finds of Euoplocephalus to about a dozen specimens. These include a number of almost complete skeletons, so much is nevertheless known about the build of the animal.

Fossil of Euoplocephalus at Senckenberg Museum of Frankfurt

Euoplocephalus was about five to six meters long and weighed over two tons. Its body was low-slung and very flat and wide, standing on four sturdy legs. Its head had a short drooping snout with a horny beak to bite off plants that were digested in the large gut. Like other ankylosaurids, Euoplocephalus was largely covered by bony armor plates, among them rows of large high-ridged oval scutes. The neck was protected by two bone rings. It could also actively defend itself against predators like Gorgosaurus using a heavy club-like tail end.

Eoraptor

Saturday, November 26, 2016

 Eoraptor by Anthony Numbat

Eoraptor, binomial name Eoraptor Lunensis, meaning ‘dawn thief’, was a species of dinosaur classified under the saurischia order of dinosauria. It is widely considered to be one of the worlds earliest dinosaurs. The Eoraptor lived during the late Triassic Period, around 230 to 190 million years ago (mya), and is believed to resemble the ancestor of all dinosaurs. It is known by well-preserved fossil records found in Argentina.

The Eoraptor, was given the name raptor but it has no relations to the Velociraptor or any dromaeosauridea. Like many early dinosaurs, had a relatively small body in comparison to dinosaurs of later periods. It had a thin body that was approximately one metre in length when fully developed, and weighed approximately 10 kilograms. A bipedal carnivore, the Eoraptor ran upright on its hind legs, while its fore limbs were only half the length of the hind legs. Each fore limb ended in a five digit hand, with three of the digits ending in large claws that were believed to be used to catch and handle prey. While it was believed to have eaten small animals, due to its like swift speed and sharp claws, the Eoraptor also possessed both herbivorous and carnivorous teeth, leading to suggestions that it may have been omnivourous.

Backbone and upper limbs outcropping from the soil, Valle de la Luna, Argentina. Photo by Eamezaga

The genus name Eoraptor is derived from the Greek word eos (ηως) meaning “dawn”, a reference to its primitive nature and the Latin word raptor meaning “plunderer”, a reference to its presumed carnivorous nature and its grasping hand. The specific name lunensis is derived from the Latin words luna meaning “moon”, and the suffix ~ensis, meaning “inhabitant”. The specific name lunensis is a reference to its place of discovery: the “Valle de la Luna”, which is Spanish for “Valley of the Moon.” This valley is so named because of its arid, otherworldly appearance, evocative of a lunar landscape. The type species is Eoraptor lunensis, which means “dawn plunderer from the Valley of the Moon”. Eoraptor was described and named by Paul Sereno, Catherine Forster, Raymond R. Rogers, and Alfredo M. Monetta in 1993.

Eoraptor skeleton

Eoraptor is thought to have been an omnivore. It was a swift sprinter and, upon catching its prey, it would use claws and teeth to tear the prey apart. Unlike later, carnivorous dinosaurs, it lacked a sliding joint at the articulation of the lower jaw, with which to hold large prey. Furthermore, only some of its teeth were curved and saw-edged, unlike those in the mouths of later theropods. The unique heterodont dentition of Eoraptor (Sereno et al., 1993) consists of both serrated, recurved teeth in the upper jaw, like the teeth of later theropods, and leaf-shaped teeth in the lower jaw, like the teeth of basal sauropodomorphs. Eoraptor had 4 teeth in the lower jaw and 18 teeth in the upper jaw, a dental formula not dissimilar to that of Herrerasaurus.

Edmontonia

Saturday, November 26, 2016

Edmontonia by Glyptodon graphycus

Edmontonia was an armoured dinosaur, part of the nodosaur family from the Late Cretaceous Period. It is named after the Edmonton Formation (now the Horseshoe Canyon Formation in Canada), the unit of rock it was found in.
 
Edmontonia was one of the largest nodosaurids, one of the two main groups of the armored ankylosaurs. Nodosaurids characteristically had a boxlike head and bony armor covering the neck, back, and upper surfaces of the tail. This armor consisted of three types of bony elements embedded in the skin. The largest were pronounced spikes, on the shoulders and forming two rows running along the sides of the animal. Shieldlike scutes of varying sizes were arranged in several rows, running lengthwise from the back of the neck to the tip of the tail. In between the scutes and spikes were thousands of small, pea-sized ossicles. Together the spikes, scutes, and ossicles formed an impenetrable shield against the attacks of predators. Even the head had a set of interlocking bony plates over the upper surfaces to protect the brain, eyes and nose.
 
Restored E. rugosidens skeleton without back armour
The huge spikes on the shoulders gave Edmontonia an offensive weapon. By tucking its bony head below them, Edmontonia could drive these spikes forward into an attacker with potentially lethal effect. As with most nodosaurids, Edmontonia’s belly was unprotected by armor and would have been vulnerable to attack if the animal were flipped over. To prevent this from happening, Edmontonia was very low-slung with relatively short, stumpy legs spread wide by broad hips and shoulder girdles. Edmontonia was built rather like a huge coffee table!
 
Edmontonia was a formidable dinosaur, with its bulky, low-slung body, armor plating along its back, and–most intimidatingly–the sharp spikes jutting out from its shoulders, which may have been used to deter predators or to fight other males for the right to mate (or both). Some paleontologists also believe Edmontonia was capable of producing honking sounds, which would truly have made it the SUV of nodosaurs.

Edmontosaurus

Saturday, November 26, 2016

Edmontosaurus

Edmontosaurus is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian stage of the Cretaceous Period 73 million years ago, while those of E. annectens were found in the same geographic region but in rocks dated to the end of the Maastrichtian stage of the Cretaceous, 66 million years ago. Edmontosaurus was one of the last non-avian dinosaurs, and lived alongside dinosaurs like Triceratops and Tyrannosaurus shortly before the Cretaceous–Paleogene extinction event.

Reconstruction of E. regalis Hai Xing, Jordan C. Mallon, Margaret L. Currie – http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0175253#pone.0175253.ref008 Reconstruction of Edmontosaurus regalis mainly based on CMN 2288, CMN 2289, CMN 8399, and UALVP 53722 (modified from Campione and Evans).

Edmontosaurus included some of the largest hadrosaurid species, measuring up to 12 metres (39 ft) long and weighing around 4.0 metric tons (4.4 short tons). Evidence does exist in the form of two fossilized specimens housed at the Museum of the Rockies for an even greater maximum size of 15 m (49 ft) and weighing 9.07 metric tons (10.00 short tons) for Edmontosaurus annectens.

The first fossils named Edmontosaurus were discovered in southern Alberta (named after Edmonton, the capital city), in the Horseshoe Canyon Formation (formerly called the lower Edmonton Formation). The type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, named by Othniel Charles Marsh in 1892; originally as a species of Claosaurus, known for many years as a species of Trachodon, and later as Anatosaurus annectensAnatosaurus and Anatotitan are now generally regarded as synonyms of Edmontosaurus.

Most known complete Edmontosaurus skulls Nicolás E. Campione, David C. Evans – Fig. 2 in Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America. PLoS ONE 6(9):e25186, doi:10.1371/journal.pone.0025186 Compilation of virtually all known complete edmontosaur skulls from North America. All skulls are in lateral view (sometimes reversed). Labels below each skull include the symbol used in the morphometric plots, whether the specimen represents a holotype (type), the formation where it was uncovered (HCF, Horseshoe Canyon Formation; HF, Hell Creek Formation; FF, Frenchman Formation; LF, Lance Formation), and the species name based on traditional edmontosaur taxonomy. Scale bar, 20 cm.

Edmontosaurus was widely distributed across western North America. The distribution of Edmontosaurus fossils suggests that it preferred coasts and coastal plains. It was a herbivore that could move on both two legs and four. Because it is known from several bone beds, Edmontosaurus is thought to have lived in groups, and may have been migratory as well. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, and its injuries and pathologies, such as evidence for tyrannosaur attacks on a few edmontosaur specimens.

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