pterosaur


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pterosaur

(tĕr`əsôr') [Gr., = winged lizard], extinct flying reptile (commonly called pterodactyl [Gr., = wing finger]) of the order Pterosauria, common in the late Triassic and Cretaceous periods, from approximately 228 to 65 million years ago. At least 60 genera of pterosaurs have been found, sizes ranging from that of a sparrow to that of the huge Quetzalcoatlus, the largest fossils of which have a wingspread of more than 40 ft (12 m), and fossilized tracks suggest that some pterosaurs may have had 60 ft (18 m) wingspans. The earlier species (e.g., Rhamporhynchus) had fully toothed jaws and long tails, but in the later forms (e.g., Pteronodon) the tail was a stump, teeth were lacking, and the jaws were modified into a beak. The skulls of different species differ markedly, presumably as a result of adaptation to capturing different kinds of prey.

The flying apparatus of pterosaurs comprised a membranous wing stretched between the fourth finger of the hand and the side of the body. The fifth finger was degenerate, and the first three were free of the wing. The "pteroid" bone, unique to the pterosaur group, attached to the wrist and pointed toward the shoulder, also helped support the wing, and the wings were strengthened by numerous connective tissue fibers. There is no fossil evidence of feathers. Most researchers now believe that pterosaurs were adapted for active flight, not just gliding as was earlier believed. Their bones are large but hollow, and they possessed a keeled breastbone for the attachment of flying muscles. Debate continues regarding how pterosaurs moved when on the ground and how maneuverable they were in the air. Pterosaurs, unlike the flying dinosaur ArchaeopteryxArchaeopteryx
[Gr.,=primitive wing], a 150 million-year-old fossil animal first discovered in 1860 in the late Jurassic limestone of Solnhofen, Bavaria, and described the following year.
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, were not ancestral to the birds but represented a wholly separate line of development. Like dinosaursdinosaur
[Gr., = terrible lizard], extinct land reptile of the Mesozoic era. The dinosaurs, which were egg-laying animals, ranged in length from 2 1-2 ft (91 cm) to about 127 ft (39 m).
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, pterosaurs were affected by the mass extinctionmass extinction,
the extinction of a large percentage of the earth's species, opening ecological niches for other species to fill. There have been at least ten such events.
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 at the end of the Cretaceous periodCretaceous period
, third and last period of the Mesozoic era of geologic time (see Geologic Timescale, table), lasting from approximately 144 to 65 million years ago. The Cretaceous was marked, in both North America and Europe, by extensive submergences of the continents.
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References in periodicals archive ?
Simpson and his colleagues identified the specimen as a new species of pterosaur - a flying reptile that lived alongside dinosaurs during the Lower Cretaceous period, 220 million years ago.
Dr Xiaolin said the pterosaurs may have been forced to leave the Jiufotang Formation due to rising competition with birds, which also prey on fish.
The fossil, originally recovered from the Gobi Desert in 1994, shows the well-preserved 75 mm long pterosaur bone lodged in the upper part of the Velociraptor ribcage where its stomach would have been.
The fossil was unearthed from the Cretaceous Cambridge Greensand of eastern England, revealing that the pterosaur lived around 100 million years ago during what is known as the Albian stage.
To be able to grow so large and still be able to fly, pterosaurs evolved incredibly lightweight skeletons, with the bones reduced to thin-walled, hollow tubes like the frame a carbon-fiber racing bike," Dr.
Researchers have proposed that "the only way pterosaurs could survive was by evolving completely crazy massive sizes," Martin-Silverstone says.
Lead author of the study Elizabeth Martin-Silverstone, a Palaeobiology PhD Student at the University of Southampton, said: This new pterosaur is exciting because it suggests that small pterosaurs were present all the way until the end of the Cretaceous, and werent outcompeted by birds.
As for the teeth assigned to pterosaurs, such long needle-like teeth could be ascribed to a marine reptile such as an ichthyosaur or a plesiosaur, or even to a pterosaur or a crocodilian.
This Cretaceous Period pterosaur boasted an unusual blade-like crest on its lower jaw like the one on the movie creatures.
In the past decade, however, there has been an explosion of pterosaur research and new fossil discoveries, including by [AMNH] scientists and the exhibition's curatorial team.
Based on the discoveries, we know that this Pterosaur lived together with other Pterosaurs and laid its eggs in the bank of the ancient lake, similar (behaviour) to that of some modern birds such as flamingos," explained Xiaolin Wang, a vertebrate paleontologist from Chinese Academy of Sciences.
Before their discovery, there had only been four flattened, two-dimensionally preserved pterosaur eggs.