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{{Automatic taxobox
| name = Dinosaur
| fossil_range = {{fossilrange|233.23|0|[[Upper Triassic]]–[[Holocene|Present]], 233.23 – 0 mya| | earliest=247.22|PS=Range includes birds (Aves) }} (Possible Middle Triassic record)
| image = Dinosauria montage 2.jpg
| image_upright = 1.2
| image_caption = A collection of fossil dinosaur skeletons. Clockwise from top left: ''[[Microraptor]]'' (a winged [[Theropoda|theropod]]), ''[[Apatosaurus]]'' (a giant [[sauropod]]), ''[[Edmontosaurus]]'' (a duck-billed [[ornithopod]]), ''[[Triceratops]]'' (a horned [[ceratopsia]]n), ''[[Stegosaurus]]'' (a plated [[stegosaur]]), ''[[Pinacosaurus]]'' (an armored [[Ankylosauria|ankylosaur]])
| taxon = Dinosauria
| authority = [[Richard Owen|Owen]], 1842
| subdivision_ranks = Major groups
| subdivision = *{{extinct}}[[Sauropodomorpha]]
* [[Theropoda]]
* {{extinct}}[[Ornithischia]]
}}

'''Dinosaurs''' are a group of [[Archosaur]] [[reptile]]s of the [[Cladistics|clade]] '''Dinosauria'''.<ref>The word 'dinosaur' comes from [[Greek language|Greek]], meaning 'terrible lizard, [{{Cite news | url = http://news.bbc.co.uk/cbbcnews/hi/find_out/guides/animals/dinosaurs/newsid_1610000/1610428.stm | title = Dinosaurs - What's in a name? | date = 26 October 2001 |publisher=Children's BBC|accessdate=2009-10-03}}] and was coined by English biologist Richard Owen in 1842. [{{Cite web | url = http://www.nhm.ac.uk/nature-online/science-of-natural-history/biographies/richard-owen/index.html | title = Richard Owen| accessdate= 2009-10-05| publisher = Natural History Museum}}]</ref> Dinosaurs eventually gave rise to [[Bird|birds]]. 

Dinosaurs were the most powerful [[Terrestrial animal|land animals]] of the [[Mesozoic]] [[era]]. Over 500 different [[genus|genera]] of dinosaurs are known.<ref>That is, fossil dinosaurs and not modern [[bird]]s.</ref> [[Fossil]]s of dinosaurs have been found on every [[continent]].

Dinosaurs began in the [[Upper Triassic]], about 230 million years ago (mya).<ref name="Alcobar2010">They may have began earlier: {{cite journal |last1=Alcobar |first1=Oscar A. |last2=Martinez |first2=Ricardo N. |title=A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina |url=https://archive.org/details/pubmed-PMC3088398 |journal=ZooKeys |date=19 October 2010 |issue=63 |doi=10.3897/zookeys.63.550 |pmc=3088398 |pmid=21594020 |pages=55–81|doi-access=free  |issn=1313-2970 }}</ref> The earliest date of a fossil is that of ''[[Eoraptor]]'' and ''[[Herrerasaurus]]'' from [[Argentina]], and ''[[Saturnalia]]'' from [[Brazil]], 237 to 228 mya.<ref>Benton M.J. 2015. ''Vertebrate palaeontology''. 4th ed,  Wiley Blackwell, p205.</ref>

By the early [[Jurassic]] they were the top land [[vertebrate]]s, and dominated most [[environment]]s on land. They continued until the [[K/T extinction event]] 66 million years ago.<ref>{{Cite web | url = http://www.nhm.ac.uk/jdsml/nature-online/dino-directory/timeline.dsml?disp=gall&per_id=&sort=Genus | publisher = Natural History Museum|accessdate=2009-10-05| title = Dino Timeline}}</ref>

From the [[fossil record]], it is known that [[bird]]s are living [[feathered dinosaur]]s.<ref name="NYT-20161208">{{cite news|url=https://www.nytimes.com/2016/12/08/science/dinosaur-feathers-amber.html|title=That thing with feathers trapped in amber? It was a dinosaur tail|last=St. Fleur|first=Nicholas|date=8 December 2016|accessdate=8 December 2016|work=[[New York Times]]}}</ref> They [[evolved]] from earlier [[theropod]]s during the later [[Jurassic]].<ref name="SCI-20140731">{{cite journal|authors=Lee, MichaelS.Y.; Cau, Andrea; Naish, Darren; Dyke, Gareth J.|date=1 August 2014|title=Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds|url=http://www.sciencemag.org/content/345/6196/562|journal=[[Science (journal)|Science]]|volume=345|issue=6196|pages=562–566|bibcode=2014Sci...345..562L|doi=10.1126/science.1252243|pmid=25082702|s2cid=37866029|accessdate=August 2, 2014}}</ref> They were the only line of dinosaurs to survive to the [[Holocene|present day]].<ref name=Holtz2007>{{cite book |author=Holtz, Thomas R. Jr. |title=Dinosaurs: the most complete, up-to-date encyclopedia for dinosaur lovers of all ages|url=https://archive.org/details/dinosaursmostcom00holt |publisher=Random House |place=New York |year=2007 |isbn=978-0-375-82419-7}}</ref>

Dinosaurs had [[adaptations]] that helped make them successful. The first known dinosaurs were small [[carnivore|predators]] that [[bipedal|walked on two legs]].<ref name=Paleos/><ref>Moderately large bipedal dinosauromorphs had appeared by 246 mya. Fossil tracks show that the dinosaur lineage appeared soon after the [[Permian-Triassic extinction event]]. Their age suggests that the rise of dinosaurs was slow and drawn out across much of the Triassic. {{cite journal |last=Brusatte S.L; Niedźwiedzki G. & Butler R.J. 2010 |title=Footprints pull origin and diversification of dinosaur stem lineage deep into early Triassic |journal=Proceedings of the Royal Society B |year=2011 |pmid=20926435 |volume=278 |issue=1708 |pages=1107–1113 |doi=10.1098/rspb.2010.1746 |pmc=3049033}}</ref> All their [[descendent|descendant]]s had an [[wikt:upright|upright]] [[wikt:posture|posture]], with the legs underneath the body. This transformed their whole life-style. Most of the smaller dinosaurs had [[feather]]s, and were probably [[warm-blooded]]. This would make them active, with a higher [[metabolism]] than modern reptiles. [[Social]] interaction, with living in [[herd]]s and co-operation, seems certain for some types. The existence of communal egg-laying sites is best understood if the adults travelled in herds, as [[herbivores]] do today.

The first fossils were recognised as dinosaurs in the early 19th century. Some of their bones were found much earlier, but were not understood. [[William Buckland]], [[Gideon Mantell]] and [[Richard Owen]] saw these bones were a special group of animals. [[Georges Cuvier]] was also important in explaining what dinosaurs were. Dinosaurs are now major attractions at [[museum]]s around the world. They have become part of [[popular culture]]. There have been best-sellng books and movies about dinosaurs. New discoveries are reported in the [[Mass media|media]].

[[File:Evolution of dinosaurs EN.svg|thumb|center|500px|Evolution of dinosaurs]]

== Features of dinosaurs ==
[[File:Dromaeosaurus skull en.svg|thumb|Labeled diagram of a typical archosaur skull, the skull of ''[[Dromaeosaurus]]'']]

Dinosaurs are so varied that it is not easy to find what they all share. A reasonable list would include many features of the [[skeleton]] which are not familiar to the general reader.<ref>Nesbitt, Sterling J. 2011. The early evolution of Archosaurs: relationships and the origin of major [[clade]]s. ''Bulletin of the American Museum of Natural History''. New York: American Museum of Natural History. 2011 (352): 1–292. doi:10.1206/352.1. hdl:2246/6112. ISSN 0003-0090. S2CID 83493714.</ref>

Dinosaurs were, at the start, small and bipedal; they walked on their hind legs. They laid eggs in nests. From the start of their fossil record, there were both [[carnivores]] and herbivores.

Changes in the basic set-up of dinosaurs happened because of [[adaptations]] to different [[lifestyle]]s. We now know that birds are the living descendants of dinosaurs, and later adapted to different lifestyles as well.

=== Adaptive radiation ===
[[Adaptive radiation]] let dinosaurs live in many [[ecological niche]]s. [[Palaeontology|Paleontologists]] have identified over 500 different [[genera]] and 1,000 [[species]] of non-avian dinosaurs.<ref name="Wang">{{cite journal|author=Wang S.C. and Dodson P.|year=2006|title=Estimating the diversity of dinosaurs|journal=Proceedings of the National Academy of Sciences USA|volume=103|issue=37|pages=13601–13605|bibcode=2006PNAS..10313601W|doi=10.1073/pnas.0606028103|pmc=1564218|pmid=16954187|doi-access=free}}</ref> Their descendants, the birds, number 9,000 living species, and are the most diverse group of land vertebrates.

The largest dinosaurs were [[herbivore]]s (plant-eaters), such as ''[[Apatosaurus]]'' and ''[[Brachiosaurus]]''. They were the largest [[animal]]s to ever walk on dry land. Other plant-eaters, such as [[Iguanodon]], had special weapons to help them fight off the meat-eaters. For example, ''[[Triceratops]]'' had three horns on its head shield, ''[[Ankylosaurus]]'' was covered in boney plates, and ''[[Stegosaurus]]'' had spikes on its tail.

The carnivores were [[bipedal]] (walked on their back legs), though they were not exactly like we are. Their body was more [[horizontal]], [[balance]]d at the back by their [[tail]]. Some were very large, like ''[[Tyrannosaurus]]'', ''[[Allosaurus]]'' and ''[[Spinosaurus]]'', but some were small, like ''[[Compsognathus]]''. It was the smaller sized meat-eaters that may have [[evolution|evolved]] into birds. The first [[fossil]] bird, ''[[Archaeopteryx]]'', had a [[skeleton]] which looked much like that of the dinosaur ''Compsognathus'', as [[T.H. Huxley]] commented.

==Types of dinosaurs==
Dinosaurs are united by at least 21 [[Trait (biology)|traits]] in their skulls and skeletons.<ref name=Nesbitt>Nesbitt S.J. 2011. The early evolution of archosaurs : relationships and the origin of major clades. ''Bulletin of the American Museum of Natural History'' '''352''': 1–292.</ref> These common characters (called '[[synapomorphy|synapomorphies]]') are the reason [[palaeontologist]]s are sure dinosaurs had a common origin.

However, when definite dinosaur [[fossil]]s appear (early in the Upper Triassic), the group had already split into two great [[Order (biology)|orders]]: the [[Saurischia]], and the [[Ornithischia]]. The Saurischia keep the ancestral hip arrangement inherited from their [[archosaur]] ancestors, and the Ornithischia have a modified hip structure.
[[File:Dino evol 1 modificated ES.svg|center|500px]]
<center>'''A'''. ''[[Eoraptor]]'', an early [[saurischia]]n, '''B''' ''[[Lesothosaurus]]'', a primitive [[ornithischia]]n, <br/>'''C''' A saurischian pelvis (''[[Staurikosaurus]]'') '''D''' ''[[Lesothosaurus]]'' pelvis</center>

===Dinosaur classification===

The following is a simplified list of dinosaur groups based on their [[evolution]].<ref name="Holtz2007"/> Groups with a dagger (†) next to them do not have any living members.
*'''Dinosauria'''
:* '''[[Saurischia]]''' ("lizard-hipped"; includes Theropoda and Sauropodomorpha)
::* '''[[Theropoda]]''' (all [[Bipedalism|bipedal]]; most were [[carnivorous]])
:::* †[[Herrerasauridae|Herrerasauria]] (early bipedal carnivores)
:::* †[[Coelophysoidea]] (small, early theropods; includes ''[[Coelophysis]]'' and its close relatives)
:::* †[[Dilophosauridae]] (early crested and carnivorous theropods)
:::* †[[Ceratosauria]] (generally elaborately horned, the dominant southern carnivores of the Cretaceous)
:::* [[Tetanurae]] (meaning "stiff tails"; includes most theropods)
::::* †[[Megalosauroidea]] (early group of large carnivores including the semiaquatic spinosaurids)
::::* †[[Carnosauria]] (''[[Allosaurus]]'' and close relatives, like ''[[Carcharodontosaurus]]'')
::::* [[Coelurosauria]] ([[feather]]ed theropods, with a range of body sizes and [[niche]]s)<ref name="NYT-20161208" />
:::::* †[[Compsognathidae]] (common early coelurosaurs)
:::::* †[[Tyrannosauridae]] (''[[Tyrannosaurus]]'' and its close relatives)
:::::* †[[Ornithomimosauria]] (meaning "[[Common ostrich|ostrich]]-mimics"; mostly toothless; carnivores to possible herbivores)
:::::* †[[Alvarezsaur]]oidea (small [[insectivore]]s with short arms that each had one large [[claw]])
:::::* [[Maniraptora]] (meaning "hand snatchers"; had long, slender arms and fingers)
::::::* †[[Therizinosaur]]ia (bipedal [[herbivore]]s with large hand claws and small heads)
::::::* †[[Oviraptorosauria]] (mostly toothless; their diet and lifestyle are uncertain)
::::::* †[[Archaeopterygidae]] (small, winged theropods or primitive birds)
::::::* †[[Dromaeosauridae#Deinonychosauria|Deinonychosauria]] (small to medium-sized, bird-like, with a distinctive toe claw.)
::::::* [[Avialae]] (modern birds and their extinct relatives)
:::::::* †[[Scansoriopteryg]]idae (small primitive avialans with long third fingers)
:::::::* †[[Omnivoropterygi]]idae (large, early short-tailed avialans)
:::::::* †[[Confuciusornith]]idae (small toothless avialans)
:::::::* †[[Enantiornith]]es (primitive flying avialans that lived in [[tree]]s)
:::::::* [[Euornith]]es (advanced flying birds)
::::::::* †[[Yanornithiform]]es (toothed [[Cretaceous]] Chinese birds)
::::::::* †[[Hesperornith]]es (specialized [[aquatic]] diving birds)
::::::::* '''[[Bird|Aves]]''' (modern, [[beak]]ed birds and their extinct relatives)
[[File:Longest_dinosaurs1.png|thumb|center|330px|Size differences of the largest [[sauropod]]s compared to a [[human]]]]
* †'''[[Sauropodomorpha]]''' (herbivores with small heads, long necks, long tails)
:::* †[[Guaibasauridae]] (small, primitive, [[omnivorous]] sauropodomorphs)
:::* †[[Plateosauridae]] (primitive, bipedal "prosauropods")
:::* †[[Riojasauridae]] (small, primitive sauropodomorphs)
:::* †[[Massospondylidae]] (small, primitive sauropodomorphs)
:::* †[[Sauropoda]] (very large and heavy, usually over {{convert|15|m|ft|abbr=on}} long; [[quadruped]]al)
::::* †[[Vulcanodontidae]] (primitive sauropods with pillar-like arms and legs)
::::* †[[Eusauropoda]] ("true sauropods")
:::::* †[[Cetiosauridae]] ("whale reptiles")
:::::* †[[Turiasauria]] ([[European]] group of [[Jurassic]] and Cretaceous sauropods)
:::::* †[[Neosauropoda]] ("new sauropods")
::::::* †[[Diplodocoidea]] (skulls and tails elongated; teeth typically narrow and pencil-like)
::::::* †[[Macronaria]] (boxy skulls; spoon- or pencil-shaped teeth)
:::::::* †[[Brachiosauridae]] (long-necked, long-armed macronarians)
:::::::* †[[Titanosaur]]ia (diverse; stocky, with wide hips; most common in the late Cretaceous of southern continents)
:* †'''[[Ornithischia]]''' ("bird-hipped"; diverse bipedal and quadrupedal herbivores)
::* †[[Heterodontosauridae]] (small basal ornithopod herbivores/omnivores with prominent [[canine tooth|canine-like teeth]])
::* †[[Thyreophora]] (armored dinosaurs; mostly quadrupeds)
:::* †'''[[Ankylosauria]]''' ([[scute]]s as primary armor; some had club-like tails)
:::* †'''[[Stegosauria]]''' (spikes and plates as primary armor)
::* †[[Neornithischia]] ("new ornithischians")
:::* †'''[[Ornithopod]]a''' (various sizes; bipeds and quadrupeds; evolved a method of chewing using flexible [[skull]]s and many [[Tooth|teeth]])
:::* †[[Marginocephalia]] (dome-like growths on their [[skull]]s made of [[bone]])
::::* †[[Pachycephalosauria]] (bipedal with domed or knobby growth on skulls)
::::* †'''[[Ceratopsia]]''' (quadrupeds with bony frills; many also had horns)
:::#

==Origins and evolution==
===Archosaurs===
The archosaurs evolved into two main [[clade]]s: those related to [[crocodile]]s, and those related to dinosaurs.
* '''[[Archosaur]]ia'''
** [[Pseudosuchia]]: clade of the [[crocodile]]s and their relatives.
** [[Avemetatarsalia]]: clade of the dinosaurs, [[pterosaur]]s, birds and relatives.
*** [[Aphanosauria]] (small group in middle [[Triassic]])
*** [[Ornithodira]]: clade of the pterosaurs and dinosaurs.
**** [[Pterosaur]]s
**** Dinosaurs

===Earliest dinosaurs===
[[File:Herrerasaurusskeleton.jpg|thumb|230px|The early forms ''[[Herrerasaurus]]'' (large), ''[[Eoraptor]]'' (small) and a ''[[Plateosaurus]]'' skull]]
The first known dinosaurs were [[bipedal]] [[carnivore|predators]] that were one to two metres long.<ref name="Paleos">Palaeos lists "probably habitually bipedal" among the characteristics of the [[Dinosauromorpha]] (that is, early proto-dinosaurs). [http://palaeos.com/pdf/phytodinosauria.pdf] {{Webarchive|url=https://web.archive.org/web/20150315060006/http://palaeos.com/pdf/phytodinosauria.pdf|date=2015-03-15}}</ref><ref>Allen, Vivian; Bates, Karl T; Li, Zhiheng and Hutchinson John R. 2013. Linking the evolution of body shape and locomotor biomechanics in bird-line archosaurs. ''[[Nature (journal)|Nature]]'' '''497''', 104–107. [http://www.nature.com/nature/journal/v497/n7447/full/nature12059.html]; popular summary [http://www.rvc.ac.uk/SML/Projects/Evolution3DDinos.cfm]</ref>

The earliest confirmed dinosaur fossils include the [[saurischia]]n ('lizard-hipped') dinosaurs ''[[Herrerasaurus]]'' 230–220&nbsp;mya, ''[[Staurikosaurus]]'' possibly 230–225&nbsp;mya, ''[[Eoraptor]]'' 231.4&nbsp;mya,<ref name="Al">Alcober O.A & Martinez R.N. 2010. A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina. ''Zookeys''. '''63''', 55{{ndash}}81. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088398/]</ref> and ''[[Alwalkeria]]'' 230–220&nbsp;mya. ''[[Saturnalia (dinosaur)|Saturnalia]]'', 232–225&nbsp;mya, may be a basal saurischian or a [[prosauropod]]. The others are basal saurischians.

Among the earliest [[ornithischia]]n ('bird-hipped') dinosaurs is ''[[Pisanosaurus]]'' 230–220&nbsp;mya. Although ''[[Lesothosaurus]]'' comes from 199 to 189&nbsp;mya, skeletal features suggest that it branched from the main Ornithischia line at least as early as ''Pisanosaurus''.

Early saurischians were similar to early ornithischians, but different from modern [[crocodile]]s. Saurischians differ from ornithischians by keeping the ancestral configuration of bones in the [[pelvis]] (shown in a diagram above). Another difference is in the skull: the upper skull of the Ornithischia is more solid, and the joint connecting the lower jaw is more flexible. These features are adaptations to [[herbivory]]; in other words, it helped them grind vegetable food.

==Life style==
===Locomotion===
Dinosaurs were primitively ''[[bipedal]]'': their probable ancestors were small bipedal Archosaurs. The date of the early dinosaur [[genus]] ''[[Eoraptor]]'' at 231.4 million years ago is important. ''Eoraptor'' probably resembles the common ancestor of all dinosaurs;<ref name="Sereno1999">{{cite journal|author=Sereno PC|title=The evolution of dinosaurs|year=1999|journal=Science|volume=284|issue=5423|pages=2137–2147|doi=10.1126/science.284.5423.2137|pmid=10381873}}</ref> its [[Trait (biology)|traits]] suggest that the first dinosaurs were small, bipedal [[predator]]s.<ref name=SFRM93>{{cite journal |last1=Sereno |first1=P.C. |authorlink=|year=1993 |title=Primitive dinosaur skeleton from Argentina and the early evolution of Dinosauria |journal=Nature |volume=361 |pages=64–66|doi=10.1038/361064a0 |last2=Forster |first2=Catherine A. |last3=Rogers |first3=Raymond R. |last4=Monetta |first4=Alfredo M.|issue=6407 |bibcode=1993Natur.361...64S |s2cid=4270484 }}</ref> The discovery of primitive, pre-dinosaur,<ref>A [[clade]] of Archosaurs ancestral to all dinosaurs and pterosaurs.</ref> types in Middle [[Triassic]] [[strata]] supports this view. Analysis of their fossils suggests that the animals were indeed small, bipedal predators.
[[File:Sprawling and erect hip joints - horiz.png|thumb|right | 300px | Hip joints and hindlimb postures]]
Those dinosaurs which returned to four-legged stance kept all four legs under their body. This is much more efficient than the sprawling legs of a [[lizard]].

The big sauropods could never have reached so large a size without their pillar-like legs. A review surveys what we know about the mechanics of dinosaur movement.<ref>Alexander, R. McNeil 2006. Dinosaur biomechanics. ''Proceedings of the Royal Society B: Biological Sciences''. '''273''' (1596): 1849–1855. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634776/] (full free access)</ref>

===Warm blooded===
A major change in outlook came in the 1960s, when it was realised that small theropods were probably warm-blooded.<ref name=Bob>Bakker, Robert T. 1986. ''The dinosaur heresies: new theories unlocking the mystery of the dinosaurs and their extinction''. Citadel N.Y.</ref> The question of whether all theropods or even all dinosaurs were warm blooded is still undecided.

It is now certain (from fossils discovered in [[China]]: see [[Jehol biota]]) that small theropods had [[feather]]s. This fits well with the idea that they were warm-blooded, and that the [[origin of birds]] can be traced to a line of small theropods.

===Activity===
Warm blooded animals have a high metabolic rate (use up food faster). They can be more active, and for longer, than animals who depend on the [[environment]] for heating. Therefore, the idea of warm-blooded dinosaurs insulated by feathers led to the idea that they were more active, intelligent and faster runners than previously thought.<ref name=Bob/>

Main-stream palaeontologists have followed this view for small theropods, but not for larger herbivores.<ref>Benton M.J 2000. ''Walking with dinosaurs: the facts''. BBC, London, Chapter 6.</ref> Since we know that the size of a ''[[Stegosaur]]'''s brain was about the size of a [[walnut]], there is good reason to think its [[Dinosaur brains and intelligence|intelligence]] was limited.

=== Limitations ===
Despite their great success over a long period, there were lifestyles which the dinosaurs never evolved. None ever evolved to live entirely in water, as many mammals do, though ''[[Spinosaurus]]'' was semi-aquatic. They never entirely dominated the small terrestrial [[niche]]. All through the [[Mesozoic]] most small vertebrates were mammals and [[lizards]].<ref>{{Cite web |url=http://palaeos.com/pdf/phytodinosauria.pdf |title=Paleos introduction |access-date=2013-05-29 |archive-date=2015-03-15 |archive-url=https://web.archive.org/web/20150315060006/http://palaeos.com/pdf/phytodinosauria.pdf |url-status=dead }}</ref> Some small dinosaurs developed into early birds. In general, we have much still to learn about the smaller fauna of the Mesozoic.

==Extinction==
[[File:KT boundary 054.jpg|thumb|[[Badlands]] near [[Drumheller]], [[Alberta]]. Erosion has exposed the [[claystone]] K/T boundary]]

The [[extinction]]s at the end of the Cretaceous were caused by a catastrophic event: a massive [[meteorite]] hit the Earth (the [[Chicxulub]] impact). We now know where it hit: in the [[Yucatán Peninsula|Yucantan peninsula]] in what is now Mexico.

Several other impact craters, and massive volcanic activity in the [[Deccan Plateau#The Deccan Traps|Deccan Traps]] in [[India]], have been dated to about the time of the extinction event. These geological events may have reduced sunlight and hindered [[photosynthesis]], leading to a massive disruption in Earth's [[ecology]].<ref name="MacLeod">{{cite journal |author=MacLeod N. | display-authors = etal|title=The Cretaceous–Tertiary biotic transition |year=1997 |journal=Journal of the Geological Society |volume=154 |issue=2 |pages=265–292 |url=https://dx.doi.org/10.1144/gsjgs.154.2.0265 |doi=10.1144/gsjgs.154.2.0265| bibcode = 1997JGSoc.154..265M| s2cid = 129654916}}</ref>

Did any terrestrial dinosaurs survive the great extinction event? Yes they did, because we now know that birds are descended from dinosaurs. But dinosaurs as generally understood were eliminated. Several fossils have been found in the [[Hell Creek Formation]] about 40,000 years later than the [[K/T extinction event]]. Many scientists dismiss the "[[Paleocene]] dinosaurs" as re-worked, that is, washed out of their original places and then re-buried in much later sediments.<ref>{{cite journal|last=Sullivan|first=RM|title=No Paleocene dinosaurs in the San Juan Basin, New Mexico|url=http://gsa.confex.com/gsa/2003RM/finalprogram/abstract_47695.htm|journal=Geological Society of America Abstracts with Programs|volume=35|issue=5|pages=15|year=2003|accessdate=2007-07-02|archive-date=2011-04-08|archive-url=https://web.archive.org/web/20110408155457/http://gsa.confex.com/gsa/2003RM/finalprogram/abstract_47695.htm|url-status=dead}}</ref> An associated skeleton (e.g. more than one bone from the same individual) found above the K/T boundary would be convincing, but no such finds have been reported.

==Dinosaurs in fiction==
:"...Dragons of the prime,<br/>that tare each other in their slime". [[Tennyson]], ''In Memoriam'',1849.
Books about dinosaurs have been popular, especially with children, but adults have also enjoyed these kinds of books. In [[Edwardian]] times, [[Arthur Conan Doyle]] wrote a [[novel]] about a [[plateau]] filled with dinosaurs which he called ''[[The Lost World]]''.

''[[Jurassic Park]]'' in 1990 started a new phase in dinosaur popular culture.

===Novel and film adaptations===
* [[Jurassic Park (novel)|''Jurassic Park'' (novel)]], a 1990 novel by [[Michael Crichton]]
** [[Jurassic Park (film)|''Jurassic Park'' (film)]], the 1993 film adaptation directed by Steven Spielberg, based on the novel
** ''[[The Lost World: Jurassic Park]]'' (1997), the second film in the series
** ''[[Jurassic Park III]]'' (2001), the third film in the series

==Related pages==
* [[List of dinosaurs]]
* [[Dinosaur brains and intelligence]]
* For "'''dinobirds'''", see [[Origin of birds]]
* [[K/T extinction event]]

==References==
{{reflist}}
{{wikispecies|Dinosauria}}
{{commonscat|Dinosauria}}

==Books==
* Bakker, Robert T. 1986. ''The Dinosaur Heresies: new theories unlocking the mystery of the dinosaurs and their extinction''. New York: Morrow. {{ISBN|0-688-04287-2}}
* Farlow J.O. and Brett-Surman M.K. (eds) 1997. ''The Complete Dinosaur''. Indiana University Press. {{ISBN|0-253-33349-0}}
* Holtz, Thomas R. Jr. 2007. ''Dinosaurs: the most complete, up-to-date encyclopedia for dinosaur lovers of all ages''. New York: Random House. {{ISBN|978-0-375-82419-7}}
* {{cite book |last1=Iggulden |first1=Hal |last2=Iggulden |first2=Conn |title=The Dangerous Book for Boys |date=2007 |publisher=HarperCollins |location=New York |isbn=978-0061243585 |pages=30–34 |chapter=Dinosaurs}}
* Paul, Gregory S. 2000. ''The Scientific American book of dinosaurs''. New York: St. Martin's Press. {{ISBN|0-312-26226-4}}
* Weishampel, David B; Dodson, Peter and Osmólska, Halszka (eds) 2004. ''The Dinosauria''. 2nd ed. Berkeley: University of California Press. {{ISBN|0-520-24209-2}}
* National Geographic: ''Dinosaurs: a new look at the prehistoric icons''. Good account of discoveries at American sites. 


[[Category:Dinosaurs| ]]