Dinosaur

dinosaursDinosaurianon-avian dinosaursnon-avian dinosaurDinodinosaurianDinosauria indet.Pachypodosauriaprehistoric monstersD
Dinosaurs are a diverse group of reptiles of the clade Dinosauria.wikipedia
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Evolution of dinosaurs

dinosaur evolutiondinosaurianfamily tree
They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.
Dinosaurs evolved within a single lineage of archosaurs 243-233 Ma (million years ago) from the Anisian to the Carnian ages, the latter part of the middle Triassic.

Feathered dinosaur

feathered dinosaursfeatheredprotofeathers
The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch.
Since scientific research began on dinosaurs in the early 1800s, they were generally believed to be closely related to modern reptiles, such as lizards.

Theropoda

theropodtheropodsTheropoda indet.
The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch.
Theropoda ( or, from Greek θηρίον "wild beast" and πούς, ποδός "foot") or theropods are a dinosaur suborder that is characterized by hollow bones and three-toed limbs.

Triassic

Triassic PeriodLate TriassicMiddle to Late Triassic
They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.
A specialized subgroup of archosaurs, called dinosaurs, first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period.

Bird

birdsAvesavian
The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch. Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the most recent common ancestor (MRCA) of Triceratops and modern birds (Neornithes), and all its descendants.
This makes them the sole surviving dinosaurs, according to cladistics.

Evolution of birds

bird evolutionavian evolutionprehistoric bird
The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch.
The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves.

Cretaceous

Cretaceous PeriodMiddle CretaceousEarly Cretaceous
They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 million years ago; their dominance continued through the Jurassic and Cretaceous periods.
These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, while dinosaurs continued to dominate on land.

Fossil

fossilsfossil recordfossilized
The fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch.
Fossils vary in size from one-micrometre (1 µm) bacteria to dinosaurs and trees, many meters long and weighing many tons.

Dinosaur renaissance

research conducted since the 1970sthe science of the time
Most research conducted since the 1970s, however, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction.
The dinosaur renaissance was a small-scale scientific revolution that started in the late 1960s, and led to renewed academic and popular interest in dinosaurs.

Sauropoda

sauropodsauropodseusauropod
While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 m and heights of 18 m and were the largest land animals of all time.
Sauropoda ( or ), or the sauropods (sauro- + -pod, "lizard-footed"), are a clade of saurischian ("lizard-hipped") dinosaurs.

Triassic–Jurassic extinction event

Triassic-Jurassic extinction eventTriassic-Jurassic boundaryend Triassic extinction event
They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 million years ago; their dominance continued through the Jurassic and Cretaceous periods.
On land, all archosaurs other than crocodylomorphs (Sphenosuchia and Crocodyliformes) and Avemetatarsalia (pterosaurs and dinosaurs), some remaining therapsids, and many of the large amphibians became extinct.

Richard Owen

OwenSir Richard OwenProfessor Owen
The taxon 'Dinosauria' was formally named in 1842 by paleontologist Sir Richard Owen, who used it to refer to the "distinct tribe or sub-order of Saurian Reptiles" that were then being recognized in England and around the world.
Owen produced a vast array of scientific work, but is probably best remembered today for coining the word Dinosauria (meaning "Terrible Reptile" or "Fearfully Great Reptile").

Jurassic Park (film)

Jurassic ParkfilmJurassic Park 3D
The large sizes of some dinosaur groups, as well as their seemingly monstrous and fantastic nature, have ensured dinosaurs' regular appearance in best-selling books and films, such as Jurassic Park.
There, billionaire philanthropist John Hammond and a small team of genetic scientists have created a wildlife park of de-extinct dinosaurs.

Megalosaurus

Megalosaurus bucklandiiScrotum humanum?Megalosaurus insignis
It has also been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria.
Megalosaurus (meaning "Great Lizard", from Greek μέγας, megas, meaning 'big', 'tall' or 'great' and σαῦρος, sauros, meaning 'lizard') is an extinct genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ago) of Southern England.

Triceratops

Triceratops horridusTriceratops prorsusUgrosaurus
Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the most recent common ancestor (MRCA) of Triceratops and modern birds (Neornithes), and all its descendants.
Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 72 million years ago (mya) in what is now North America.

Iguanodon

Iguanodon bernissartensisIguanadonTherosaurus
It has also been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria.
Iguanodon (meaning "iguana-tooth"), named in 1825, is a genus of ornithopod dinosaur that existed roughly halfway between the first of the swift bipedal hypsilophodontids of the mid-Jurassic and the duck-billed dinosaurs of the late Cretaceous.

Cretaceous–Paleogene extinction event

extinction of the dinosaursCretaceous-Paleogene extinction eventK-Pg extinction event
As such, birds were the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event approximately 66 million years ago.
A wide range of species perished in the K–Pg extinction, the best-known being the non-avian dinosaurs.

Pterosaur

pterosaursPterosauriapterodactyl
Other prehistoric animals, including pterosaurs, mosasaurs, ichthyosaurs, plesiosaurs, and Dimetrodon, while often popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs.
Pterosaurs are often referred to by popular media or the general public as "flying dinosaurs", but dinosaurs are defined as the descendants of the last common ancestor of the Saurischia and Ornithischia, which excludes the pterosaurs.

Hadrosauridae

hadrosauridhadrosaurhadrosaurs
Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Hadrosaurids (ἁδρός, hadrós, "stout, thick"), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae.

Stegosauria

stegosaurstegosaursstegosaurid
Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Stegosauria is a group of herbivorous ornithischian dinosaurs that lived during the Jurassic and early Cretaceous periods.

Reptile

reptilesReptiliaSauropsida
Dinosaurs are a diverse group of reptiles of the clade Dinosauria.
The British anatomist Thomas Henry Huxley made Latreille's definition popular and, together with Richard Owen, expanded Reptilia to include the various fossil "antediluvian monsters", including dinosaurs and the mammal-like (synapsid) Dicynodon he helped describe.

Ceratopsia

ceratopsianceratopsiansneoceratopsia
Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic.

Armour (anatomy)

armorarmouredarmour
Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines.
Dinosaurs such as Ankylosaurus, as well as other Thyreophora (armoured dinosaurs such as Ankylosauria and Stegosauria), grew thick plate-like armour on their bodies as well as offensive armour appendages such as the thagomizer or a club.

Ankylosauria

ankylosaurankylosaursankylosaurian
Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Ankylosauria is a group of mainly herbivorous dinosaurs of the order Ornithischia.

Saurischia

saurischianEusaurischiaeusaurischian
Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Saurischia (, meaning "reptile-hipped" from the Greek ' meaning 'lizard' and ' meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia).