Reply #107: Cute theory, but let's actually look it up, shall we? [View All]

[beam me up scottie]

American Heritage:

di·no·saur (dī'nə-sôr')
n.
Any of various extinct, often gigantic, carnivorous or herbivorous reptiles of the orders Saurischia and Ornithischia that were chiefly terrestrial and existed during the Mesozoic Era.
A relic of the past: “living dinosaurs of the world of vegetation” (John Olmsted).
One that is hopelessly outmoded or unwieldy: “The old, big-city teaching hospital is a dinosaur”

Science and Technology Encyclopedia

The term Dinosauria (Greek, “terrible lizards” ) was coined by the British comparative anatomist Richard Owen in 1842 to represent three partly known, impressively large fossil reptiles from the English countryside: the carnivore Megalosaurus, the duckbilled Iguanodon, and the armored Hylaeosaurus.

As dinosaurs became better known, their taxonomy and classification developed, as well as their diversity. In 1888 H. G. Seeley recognized two quite different hip structures in dinosaurs and grouped them accordingly. Saurischia, including the carnivorous Theropoda and the giant, long-necked Sauropoda, retained the generalized reptilian hip structure in which the pubis points down and forward and the ischium points down and backward. The remaining dinosaurs have a pubis that also points down and backward, and lies parallel to the ischium; this reminded Seeley of the configuration in birds, and so he named this group Ornithischia. However, the ornithischian pubis is only superficially similar to that of birds, which are descended from, and are thus formally grouped in, Saurischia. Seeley's discovery, in fact, only recognized the distinctness of Ornithischia, but he concluded that Saurischia and Ornithischia were not particularly closely related. Even within Saurischia, there were general doubts that Sauropoda and Theropoda had any close relationship. In 1974 it was argued that there were a great many unique features, including warm-bloodedness, that diagnosed the dinosaurs as a natural group, including their descendants the birds. A 1986 analysis listed nine uniquely derived features of the skull, shoulder, hand, hip, and hindlimb that unite Dinosauria as a natural group; this analysis has been since modified and improved, and today Dinosauria is universally accepted as a natural group, divided into Ornithischia and Saurischia. See also Ornithischia; Saurischia.

Dinosaurs are archosaurs, a group that includes crocodiles, birds, and all the descendants of their most recent common ancestor. The closest relatives of dinosaurs, which evolved with them in the Middle and Late Triassic (about 225 million years ago), include the flying pterosaurs and agile, rabbit-sized forms such as Lagosuchus and Lagerpeton. The common ancestor of all these forms was small, lightly built, bipedal, and probably an active carnivore or omnivore. Somewhat larger, with skulls ranging 15–30 cm (6–12 in.) in length, were Eoraptor and Herrerasaurus from the Late Triassic of Argentina, and Staurikosaurus from the early Late Triassic of Brazil. They were thought to be primitive saurischian dinosaurs, but it was later determined that they were outside the group formed by Saurischia plus Ornithischia, a view generally followed. In reconsidering these genera plus the more recently discovered Eoraptor, it has been argued that all three are both saurischians and theropods. However, they lack some features of both groups, so their position remains controversial. This testifies to a burst of evolutionary change at this very interesting time in vertebrate history, and it shows that there are a variety of taxa that are very close to the origin of dinosaurs. The first definite ornithischians and saurischians appear at almost the same time as these taxa, though dinosaurs remained generally rare and not very diverse components of terrestrial faunas until the beginning of the Jurassic Period (about 200 million years ago). See also Jurassic; Triassic.

Unless your parrot is millions of years old, he's not a dinosaur.


Britannica Concise:

dinosaur

Any of the extinct reptiles that were the dominant land animals during most of the Mesozoic Era (248–65 million years ago). The various species appeared at different times, and not all overlapped. The shape of the teeth reveal whether a given dinosaur was a carnivore or herbivore. Dinosaurs are classified as either ornithischians or saurischians, based on pelvic girdle structure. Most had a long tail, which they held straight out, apparently to maintain balance. Most, if not all, were egg layers. Some were probably warm-blooded. Dinosaur fossils have been found on every continent, including Antarctica. Most types of dinosaurs flourished until late in the Cretaceous Period (65 million years ago), then disappeared within the next million years. Two theories for the cause of this mass extinction, following some 140 million years of existence, are that mountain-building cycles altered habitat and changed climate or that an asteroid hit the Earth, resulting in immense dust clouds that blocked sunlight for several years. Birds are thought to be living descendants of the dinosaurs.

Columbia Encyclopedia:

dinosaur (dī'nəsôr) , extinct land reptile of the Mesozoic era. The dinosaurs, which were egg-laying animals, ranged in length from 21/2 ft (91 cm) to about 127 ft (39 m). Recognized discoveries of fossilized dinosaur bones date only to the 1820s; Sir Richard Owen, a Victorian anatomist, coined the term dinosaur.

From Wikipedia:

dinosaur


Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. At the end of the Cretaceous period 65 million years ago, dinosaurs suffered a catastrophic extinction, which ended their dominance on land. Modern birds are considered to be the direct descendants of theropod dinosaurs.

Since the first dinosaur was recognized in the 19th century, their mounted, fossilized skeletons have become major attractions at museums around the world. Dinosaurs have become a part of world culture and remain consistently popular, especially among children. They have been featured in best-selling books and blockbuster films such as Jurassic Park, and new discoveries are regularly covered by the media.

The term dinosaur is sometimes used informally to describe other prehistoric reptiles, such as the pelycosaur Dimetrodon, the winged pterosaurs, and the aquatic ichthyosaurs, plesiosaurs, and mosasaurs, though technically none of these were dinosaurs.

What is a dinosaur?

Definition

The superorder or clade "Dinosauria" was formally named by the English scientist Richard Owen in 1842. The term is derived from the Greek words δεινός (deinos - "terrible", "fearsome" or "formidable") and σαύρα (saura; "lizard" or "reptile"). Owen chose it to express his awe at the size and majesty of the extinct animals, not out of fear or trepidation at their size and often-formidable arsenal of teeth and claws.

Dinosaurs were extremely varied. Some were herbivorous, others carnivorous. Some dinosaurs were bipeds, some were quadrupeds, and others — such as Ammosaurus and Iguanodon — could walk easily on two or four legs. Regardless of body type, nearly all known dinosaurs were well-adapted for a predominantly terrestrial, rather than aquatic or aerial, habitat.

more from Wiki:

Feathers

Archaeopteryx, the first good example of a "feathered dinosaur", was discovered in 1861. The initial specimen was found in the Solnhofen limestone in southern Germany, which is a lagerstätte, a rare and remarkable geological formation known for its superbly detailed fossils. Archaeopteryx is a transitional fossil, with features clearly intermediate between those of modern reptiles and birds. Brought to light just two years after Darwin's seminal The Origin of Species, its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. This early bird is so dinosaur-like that, without a clear impression of feathers in the surrounding rock, specimens are commonly mistaken for Compsognathus.

Since the 1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. Most of these specimens were unearthed in the Liaoning province in northeastern China, which was part of an island continent during the Cretaceous period. Though feathers have been found only in the lagerstätte of the Yixian Formation and a few other places, it is possible that dinosaurs elsewhere in the world were also feathered. The lack of widespread fossil evidence for feathered dinosaurs may be due to the fact that delicate features like skin and feathers are not often preserved by fossilization and thus are absent from the fossil record.

The feathered dinosaurs discovered so far include Beipiaosaurus, Caudipteryx, Dilong, Microraptor, Protarchaeopteryx, Shuvuuia, Sinornithosaurus, Sinosauropteryx, and Jinfengopteryx. Dinosaur-like birds like Confuciusornis, which are anatomically closer to modern avians, have also been discovered. All of these specimens come from the same formation in northern China. The dromaeosauridae family in particular seems to have been heavily feathered, and at least one dromaeosaurid, Cryptovolans, may have been capable of flight.

Skeleton

Because feathers are often associated with birds, feathered dinosaurs are often touted as the missing link between birds and dinosaurs. However, the multiple skeletal features also shared by the two groups represent the more important link for paleontologists. Furthermore, it is increasingly clear that the relationship between birds and dinosaurs, and the evolution of flight, are more complex topics than previously realized. For example, while it was once believed that birds evolved from dinosaurs in one linear progression, some scientists, most notably Gregory S. Paul, conclude that dinosaurs such as the dromaeosaurs may have evolved from birds, losing the power of flight while keeping their feathers in a manner similar to the modern ostrich and other ratites.