Description[ edit ] The anatomy of pterosaurs was highly modified from their reptilian ancestors by the adaption to flight. Pterosaur bones were hollow and air-filled, like the bones of birds. They had a keeled breastbone that was developed for the attachment of flight muscles and an enlarged brain that shows specialised features associated with flight. Wings[ edit ] Reconstructed wing planform of Quetzalcoatlus northropi A compared to the wandering albatross Diomedea exulans B and the Andean condor Vultur gryphus C. These are not to scale; the wingspan of Q. Pterosaur wings were formed by membranes of skin and other tissues. The primary membranes attached to the extremely long fourth finger of each arm and extended along the sides of the body to the ankles. While historically thought of as simple leathery structures composed of skin, research has since shown that the wing membranes of pterosaurs were highly complex dynamic structures suited to an active style of flight.
The other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida the reptile and bird clade , with the exception of Dimetrodon which is a synapsid. Definition Triceratops skeleton, Natural History Museum of Los Angeles County Under phylogenetic nomenclature , dinosaurs are usually defined as the group consisting of the most recent common ancestor MRCA of Triceratops and Neornithes , and all its descendants. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder.
However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy; this approach requires that, for a group to be natural, all descendants of members of the group must be included in the group as well.
From the limited number of fossil fragments, adding up to a single partial skeleton, most paleontologists believe that Gasosaurus resembled a vastly scaled-down Allosaurus, its fellow (and more famous) theropod of the late Jurassic period (about million years ago), though its arms were proportionately a bit longer compared to its overall size.. However, because so little is known about.
It had a big head 4. It had 17 inch 43 cm long spikes extending from its vertebrae along the neck and tail that may have formed a thick, fleshy sail on its back. It had powerful arms and each hands had three fingers, each equipped with long, sickle-like claws. It weighed roughly tons Acrocanthosaurus lived during the early Cretaceous period , roughly million million years ago in the tropics near sea level in what is now Oklahoma, Texas, and Utah, USA. It is known from incomplete skeletons and teeth and was named by paleontologists Stovall and Langston in Acrocanthus was named by paleontologists Czaplewski, Cifelli, and Langston in , but was attributed to Langston, Actiosaurus was named by Sauvage in These bony fish evolved during the very end of the Silurian, about million years ago.
These fish dominate the seas today. Sharks are not ray-finned fish.
The Upper Jurassic took place million to million years ago, and before thelatest find, dinosaur eggs had only been found from the Upper Cretaceous, a period that ran from about 90 million to 64 million years ago, and from the Lower Jurassic, which spanned million to million years ago. In findings published in the journal Science, Karl Hirsch of the University of Colorado Museum and his colleagues said they found the nearly complete egg in the Cleveland-Lloyd Dinosaur Quarry in east-central Utah.
The quarry, which has yielded more than 12, dinosaur bones, may have once been a shallow lake or marsh where dinosaurs became trapped in mud, they said.
According to WorldDailyNewsReport: Berlin: A malfunction with the heating system of the Museum für Naturkunde (or Museum of Natural History) had some unforeseen consequences, as a Gasosaurus egg.
Geologic Timescale table Geologic Timescale Era Period Epoch Approximate duration millions of years Approximate number of years ago millions of years Cenozoic Quaternary Holocene 10, years ago to the present Pleistocene 2. Click the link for more information. Great crustal disturbances that marked the close of the Paleozoic and the beginning of the Mesozoic eras brought about drastic changes in the At the start of the Jurassic most of the continents were joined together until the Atlantic began to form and the Americas split off from Africa.
Eastern North America was mostly elevated and subject to erosion, which reduced the Appalachian region to a peneplain. Before the end of the period, the Appalachian borderland began to founder as the Atlantic Ocean continued to widen. The Pacific border of North America, from California to Alaska, was submerged for most of the period. In the Early Jurassic, large areas of Arizona, Colorado, and Utah were apparently desert, and the sand was later consolidated into the white and pinkish Glen Canyon and Navajo sandstones, which now enhance the scenic beauty of the district.
During the Upper Jurassic, the Logan Sea entered this area from the north. In its various advances and retreats, this body of water covered large areas of Montana, Idaho, Wyoming, Colorado, and Utah, depositing sandstone, shale, limestone, and some gypsum. The retreat of the Logan Sea, toward the end of the period, was followed, probably in the Upper Jurassic but possibly in the Lower Cretaceous Period, by the deposition of the Morrison continental series of clays and sandstones, noted for its richness in fossil dinosaurs.
The close of the Jurassic in North America was marked by widespread folding along the western border of the continent, accompanied by the intrusion of lava as the eastern edge of the plate that carries the Pacific Ocean was thrust beneath the westward drifting plate that carries the North American continent. The history of the European Jurassic is very well known, that system being one of the most complete on the Continent.
No glaciers existed during this period.
Z Click on an underlined word for more information on that subject. If the dinosaur or paleontology term you are looking for is not in the dictionary, please e-mail us. The Top Paleontologists and Dinosaur Hunters of All Time A paleontologist is a scientist who studies paleontology, learning about the forms of life that existed in former geologic periods, chiefly by studying fossils.
Gasosaurus (Chinese: 气龙属) (/ ɡ ˈ æ s ə ˈ s ɔːr ə s /) is a genus of tetanuran theropod that lived approximately to million years ago during the middle of the Jurassic Period.
Could not subscribe, try again laterInvalid Email A cluster of perfectly preserved dinosaur eggs have been discovered by construction workers digging the foundations for a new school. The fossilised eggs were lucky to survive in tact as the builders detonated an explosive to break up a large boulder. As they approached to take away the pieces, the workers saw a nest of eggs with some fragments of black shell – up to 2mm thick – laying among them.
Construction workers found up to 30 dinosaur eggs as they prepared to build a new school on Christmas Day Image: The staff identified the eggs as being about million years old, putting them in the Cretaceous Period, which came immediately after the Jurassic Period. The Cretaceous began million years ago and ended 66 million years ago. It was succeeded by the Paleogene Period. Construction workers called police who brought in experts from the Dayu County Museum, where the eggs are being kept Image: A tick filled with the blood of a dinosaur was discovered frozen in amber Image: PA Read More Mysterious dinosaur-like creature discovered with flesh still on its bones leaves scientists baffled The seventh, the Corythoraptor jacobsi, was only discovered this year and is said to closely resemble the flightless cassowary, which lives in Australia, Papua New Guinea and Indonesia.
The eggs are being kept at the county museum for further studies.
Ice Age Giants click to play it. Question by author stephgm Wide tail Castoroides is the largest rodent known to have lived in the Americas. During the Ice Age, this herbivore lived around water sources and ate mainly aquatic plants. Its fossils show that it had large hind feet to help propel it through the water, a flat but narrow tail, and big incisors. However, these teeth are shaped differently than modern beavers and prove that it ate softer plants and probably did not cut wood and build dams.
A malfunction with the heating system of the Museum für Naturkunde (or Museum of Natural History) had some unforeseen consequences, as a Gasosaurus egg dating from the Jurassic period ended up.
Vampyronassa Ambondro Mohabo The Ambondro Mohabo is a mammal that thrived during the middle of the Jurassic period around million years ago. The Ambondro Mohabo lived in what is now Madagascar and is only known from the remnants of its lower jaw, including three lower teeth: While not too much can be determined by such minute remains, researchers have been able to determine that the teeth are similar to those of marsupial and placental mammals. More recent discussion of these limited remains indicate that the Ambondro Mohabo may actually have been related to monotremes and belong in the Australosphenida clade.
Researchers hope to recover more remains of Ambondro Mohabo in order to be able to build a better picture of what this creature actually looked like! Apiocrinites The Apiocrinites is a genus of crinoid that existed in the mid to late Jurassic period throughout Europe and Asia. Crinoids are marine creatures that compose the Crinoidea class. These animals were found in shallow and deep waters and attach to the sea bottom or rocks or corals.
These creatures had a mouth that sits at the top of the animal and feeding arms surrounding it to capture and pull food to the mouth. Some Crinoids live their lives attached to the ocean floor or a solid surface; others are free-floating after adulthood begins. Castorocauda The Castorocauda is a small semi-aquatic mammal that was found in the upper Jurassic period million years ago. Physically this creature resembles a cross between an otter and a beaver of today. The remains of Castorocauda were found in lakebed sediment in the Daohugou Beds in Mongolia.
One of the most amazing things about this mammal is the various specialized adaptations that it had developed.
Berlin| A breakdown with the warming arrangement of the Museum für Naturkunde (or Museum of Natural History) had some unforeseen outcomes, as a Gasosaurus egg dating from the Jurassic period wound up bring forth, conceiving the first dinosaur to see the light in more than million years.
A malfunction with the heating system of the Museum für Naturkunde (or Museum of Natural History) had some unforeseen consequences, as a Gasosaurus egg dating from the Jurassic period ended up hatching, giving birth to the first dinosaur to see the daylight in more than million years.