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Riga 281:
| [[Thelodonts]] ''(nipple teeth)'' are a class of small, extinct jawless fishes with distinctive scales instead of large plates of armour. There is debate over whether these represent a [[Monophyly|monophyletic grouping]], or disparate stem groups to the major lines of [[Agnatha|jawless]] and [[Gnathostome|jawed fish]].{{r|Turner1982}} Thelodonts are united by their characteristic "thelodont scales". This defining character is not necessarily a result of shared ancestry, as it may have been [[Convergent evolution|evolved independently by different groups]]. Thus the thelodonts are generally thought to represent a polyphyletic group.{{sfn|Sarjeant|Halstead}} If they are monophyletic, there is no firm evidence on what their ancestral state was.{{sfn|Donoghue|2000|p=206}} These scales were easily dispersed after death; their small size and resilience makes them the most common vertebrate fossil of their time.{{sfn|Turner1999|p=42–78}}{{r|Palaeos: Thelodonti}} The fish lived in both freshwater and marine environments, first appearing during the [[Ordovician]], and perishing during the [[Late Devonian extinction|Frasnian–Famennian extinction event]] of the Late [[Devonian]]. They were predominantly deposit-feeding bottom dwellers, although some species may have been pelagic.
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| colspan="3" style="line-height:16px; background:#dddddd;"| <small>The Ordovician ended with the [[Ordovician–Silurian extinction event]] (450–440 Ma). Two events occurred that killed off 27% of all families, 57% of all genera and 60% to 70% of all species.{{r|Baez2006}} Together they are ranked by many scientists as the second largest of the five major extinctions in Earth's history in terms of percentage of [[genus|genera]] that went extinct.</small>
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! rowspan=7 style=background:#60C090 | [[Siluriano]]
Riga 487:
! colspan=4 | Transition from lobe-finned fishes to tetrapods
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| [[File:Eusthenopteron model.jpg|140px]]<small>~385 milioni di anni fa</small>
| ''[[Eusthenopteron]]''
| {{ external media
Riga 500:
| ''[[Gogonasus]] (snout from Gogo)'' was a lobe-finned fish known from 3-dimensionally preserved 380 million-year-old fossils found in the [[Gogo Formation]]. It was a small fish reaching 30–40 cm (1 ft) in length.<ref>http://dinosaurs.about.com/od/tetrapodsandamphibians/p/gogonasus.htm</ref> Its skeleton shows several tetrapod-like features. They included the structure of its [[middle ear]], and its fins show the precursors of the forearm bones, the [[radius]] and [[ulna]]. Researchers believe it used its forearm-like fins to dart out of the reef to catch prey. ''Gogonasus'' was first described in 1985 by [[John A. Long]]. For almost 100 years ''[[Eusthenopteron]]'' has been the role model for demonstrating stages in the evolution of lobe-finned fishes to tetrapods. ''Gogonasus'' now replaces ''Eusthenopteron'' in being a better preserved representative without any ambiguity in interpreting its anatomy.
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| [[File:Panderichthys BW.jpg|140px]]<br /><small>~385 milioni di anni fa</small>
| ''[[Panderichthys]]''
| Adapted to muddy shallows, and capable of some kind of shallow water or terrestrial body flexion locomotion. Had the ability to prop itself up.<ref>Nature: [http://www.nature.com/nature/journal/v438/n7071/edsumm/e051222-13.html The pelvic fin and girdle of ''Panderichthys'' and the origin of tetrapod locomotion]</ref><br /> They had large tetrapod-like heads, and are thought to be the most crownward stem fish-tetrapod with paired fins.
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| [[File:Tiktaalik BW.jpg|140px]]<br /><small>~375 milioni di anni fa</small>
| ''[[Tiktaalik]]''
| A fish with limb-like fins that could take it onto land.<ref name=Nature>{{cite journal | journal = [[Nature (journal)|Nature]] | volume = 440 | pages = 757–763 | date = 6 April 2006 | doi = 10.1038/nature04639 | title = A Devonian tetrapod-like fish and the evolution of the tetrapod body plan | url = http://www.nature.com/nature/journal/v440/n7085/abs/nature04639.html | author = Edward B. Daeschler, Neil H. Shubin and Farish A. Jenkins, Jr | pmid = 16598249 | issue = 7085}}</ref> It is an example from several lines of ancient sarcopterygian fish developing adaptations to the oxygen-poor shallow-water habitats of its time, which led to the evolution of tetrapods.<ref name="scientificamerican">[[Jennifer A. Clack]], ''Scientific American'', [http://www.scientificamerican.com/article.cfm?id=getting-a-leg-up-on-land ''Getting a Leg Up on Land''] Nov. 21, 2005.</ref> Paleontologists suggest that it is representative of the [[transitional fossil|transition]] between non-tetrapod vertebrates (fish) such as ''[[Panderichthys]]'', known from fossils 380 million years old, and early tetrapods such as ''[[Acanthostega]]'' and ''[[Ichthyostega]]'', known from fossils about 365 million years old. Its mixture of primitive fish and derived tetrapod characteristics led one of its discoverers, [[Neil Shubin]], to characterize ''Tiktaalik'' as a "[[Tetrapodomorpha|fishapod]]".<ref>John Noble Wilford, ''The New York Times'', [http://www.nytimes.com/2006/04/05/science/05cnd-fossil.html?hp&ex=1144296000&en=fe3427d67e965e46&ei=5094&partner=homepage ''Scientists Call Fish Fossil the Missing Link''], Apr. 5, 2006.</ref><ref name="Shubin 2008">{{cite book|last=Shubin|first=Neil|title=Your Inner Fish|publisher=Pantheon|year=2008|isbn=978-0-375-42447-2}}</ref>
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| [[File:Acanthostega BW.jpg|140px]]<br /><small>365 milioni di anni fa</small>
| ''[[Acanthostega]]''
| A fish-like early [[Labyrinthodontia|labyrinthodont]] which occupied weed-filled swamps and changed views about the early evolution of tetrapods.{{r|Clack2005}} [[Polydactyly in early tetrapods|It had eight digits]] on each hand (the number of digits on the feet is unclear) linked by webbing, it lacked wrists, and was generally poorly adapted to come onto land.<ref>"[http://www.devoniantimes.org/Order/re-acanthostega.html Acanthostega gunneri]," ''Devonian Times''.</ref> Sunsequent discoveries revealed earlier transitional forms between ''Acanthostega'' and completely fish-like animals.{{r|Daeschler2006}}
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| [[File:Ichthyostega BW.jpg|140px]]<br /><small>374–359 milioni di anni fa</small>
| ''[[Ichthyostega]]''
| {{ external media
Riga 522:
Until finds of other early tetrapods and closely related fishes in the late 20th century, ''[[Ichthyostega]]'' stood alone as the transitional fossil between fish and tetrapods, combining a fishlike tail and gills with an amphibian skull and limbs. It possessed lungs and limbs with seven digits that helped it navigate through shallow water in weed-filled swamps.
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| [[File:Pederpes22small.jpg|140px]]<br /><small>359–345 milioni di anni fa</small>
| ''[[Pederpes]]''
| ''[[Pederpes]]'' is the earliest known fully terrestrial tetrapod. It is included here to complete the transition of lobe-finned fishes to tetrapods, even though ''Pederpes'' is no longer a fish.
Riga 568:
| ''[[Acanthodes]]'' are an extinct genus of [[Acanthodii|spiny shark]].<ref>{{cite journal|year=1880|title=Proceedings of the Royal Physical Society of Edinburgh|volume= V.|pages=p115|url=http://books.google.com/?id=69kKAAAAIAAJ&pg=PA115&dq=Acanthodes+extinct|doi=10.1111/|author1=Edinburgh, Royal Physical Society of}}</ref> It had [[gill]]s but no [[teeth]],<ref name="Nicholson">{{cite book|last=Nicholson|first=Henry Alleyne|coauthors=Richard Lydekker|title=A Manual of Palaeontology|year=1889|url=http://books.google.com/?id=MoAXAAAAYAAJ&pg=PA966&dq=Acanthodes+pectoral+fins|page=966}}</ref> and was presumably a [[filter feeder]].<ref name=EoDP/> ''Acanthodes'' had only two skull bones and were covered in cubical scales. Each paired [[pectoral fin|pectoral]] and [[pelvic fin]]s had one spine, as did the single [[anal fin|anal]] and [[dorsal fin]]s, giving it a total of six spines, less than half that of many other spiny sharks.<ref name=EoDP>{{cite book |editor=Palmer, D.|year=1999 |title= The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|publisher= Marshall Editions|___location=London|pages= 30–31|isbn= 1-84028-152-9}}</ref> Acanthodians share qualities of both bony fish (osteichthyes) and cartilaginous fish (chondrichthyes), and it has been suggested that they may have been stem chondrichthyans and stem gnathostomes.<ref>Article on Acanthodes as ancestor of Man, http://www.sci-news.com/paleontology/article00396.html, accessed 15 June 2012</ref><ref>Journal article on Acanthodes, http://www.nature.com/nature/journal/v486/n7402/full/nature11080.html, accessed 15 June 2012</ref>
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| colspan="3" style="line-height:16px; background:#dddddd;"| <small>The Permian ended with the most extensive [[extinction event]] recorded in [[paleontology]]: the [[Permian-Triassic extinction event]]. 90% to 95% of marine species became [[Extinction|extinct]], as well as 70% of all land organisms. It is also the only known mass extinction of insects.<ref>http://geology.about.com/od/extinction/a/aa_permotrias.htm</ref><ref>http://www.kgs.ku.edu/Extension/fossils/massExtinct.html</ref> Recovery from the Permian-Triassic extinction event was protracted; land ecosystems took 30M years to recover,<ref name="SahneyBenton2008RecoveryFromProfoundExtinction">{{cite journal | url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596898/?tool | author=Sahney, S. and Benton, M.J. | year=2008 | title=Recovery from the most profound mass extinction of all time | journal=Proceedings of the Royal Society: Biological | doi=10.1098/rspb.2007.1370 | volume = 275 | pages = 759–65|format=PDF | pmid=18198148 | issue=1636 | pmc=2596898}}</ref> and marine ecosystems took even longer.{{r|Baez2006}}</small>
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! rowspan=5 style="background:#228b22" | [[Triassico|<span style="color:white;">Triassico</span>]]
| colspan="3" style="text-align:center; background:#ddf8f8;"| [[Triassico]] (252–201 Ma): The fish fauna of the Triassic was remarkably uniform, reflecting the fact that very few families survived the Permian extinction. A considerable radiation of ''ray-finned fishes]]'' occurred during the Triassic, laying the foundation for many modern fishes.<ref>[http://www.seaworld.org/animal-info/info-books/bony-fish/scientific-classification.htm Bony fishes] ''[[SeaWorld]]''. Retrieved 2 February 2013.</ref> ''See [[:Category:Triassic fish]].''
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| [[File:Perleidus.jpg|140px]]
Riga 586:
| ''[[Pholidophorus]]'' was an [[extinct]] genus of [[teleost]], around {{convert|40|cm|in}} long, from about 240–140 Ma. Although not closely related to the modern [[herring]], it was somewhat like them. It had a single [[dorsal fin]], a symmetrical tail, and an [[anal fin]] placed towards the rear of the body. It had large eyes and was probably a fast swimming predator, hunting [[plankton]]ic [[crustacean]]s and smaller fish.{{sfn|The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|1999|p=38–39}} A very early [[teleost]], ''Pholidophoris'' had many primitive characteristics such as [[ganoid scale]]s and a [[Vertebral column|spine]] that was partially composed of [[cartilage]], rather than [[bone]].{{sfn|The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|1999|p=38–39}}
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| colspan="3" style="line-height:16px; background:#dddddd;"| <small>The Triassic ended with the [[Triassic–Jurassic extinction event]]. About 23% of all families, 48% of all genera (20% of marine families and 55% of marine genera) and 70% to 75% of all species went extinct.<ref name="ucr">{{cite web|url=http://math.ucr.edu/home/baez/extinction |title=extinction |publisher=Math.ucr.edu |date= |accessdate=2008-11-09}}</ref> Non-dinosaurian archosaurs continued to dominate aquatic environments, while [[Diapsid#Taxonomy|non-archosaurian diapsids]] continued to dominate marine environments.<ref name="ucr" /></small>
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! rowspan=3 style="background:#3cb371" | [[Giurassico]]
Riga 633:
Il più grande dei [[teleostei]] conosciuti, questo pesce del Cretacico raggiungeva una lunghezza di 4,5 metri <ref>Rafferty, John P (2010) [http://books.google.co.nz/books?id=kFd-1DApcRYC&pg=PA219&dq=%22Cretaceous+fish%22+OR+%22Cretaceous+fishes%22&hl=en&sa=X&ei=HkrtUNPWHonKlAWshYGQBQ&ved=0CKEBEOgBMBM#v=onepage&q=%22Cretaceous%20fish%22%20OR%20%22Cretaceous%20fishes%22&f=false ''The Mesozoic Era: Age of Dinosaurs''] pag. 219, Rosen Publishing Group. ISBN 9781615301935.</ref>.
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| colspan="3" style="line-height:16px; background:#dddddd;"| <small>The end of the Cretaceous was marked by the [[Cretaceous–Paleogene extinction event]] (K-Pg extinction). There are substantial fossil records of [[Gnathostomata|jawed]] [[fish]]es across the K–T boundary, which provides good evidence of extinction patterns of these classes of marine vertebrates. Within [[Chondrichthyes|cartilaginous fish]], approximately 80% of the [[shark]]s, [[Rajiformes|rays]], and [[skate]]s families survived the extinction event,<ref name="MacLeod">{{cite journal|author=MacLeod, N, Rawson, PF, Forey, PL, Banner, FT, Boudagher-Fadel, MK, Bown, PR, Burnett, JA, Chambers, P, Culver, S, Evans, SE, Jeffery, C, Kaminski, MA, Lord, AR, Milner, AC, Milner, AR, Morris, N, Owen, E, Rosen, BR, Smith, AB, Taylor, PD, Urquhart, E & Young, JR|title=The Cretaceous–Tertiary biotic transition|year=1997|journal=Journal of the Geological Society|volume=154|issue=2|pages=265–292|url=http://findarticles.com/p/articles/mi_qa3721/is_199703/ai_n8738406/print|doi=10.1144/gsjgs.154.2.0265}}</ref> and more than 90% of [[teleostei|teleost fish]] (bony fish) families survived.<ref>{{cite book |last=Patterson|first=C |year=1993 |title=Osteichthyes: Teleostei. In: The Fossil Record 2 (Benton, MJ, editor) |publisher=Springer |pages=621–656 |isbn=0-412-39380-8}}</ref> There is evidence of a mass kill of bony fishes at a fossil site immediately above the K–T boundary layer on [[Seymour Island]] near Antarctica, apparently precipitated by the K–Pg extinction event.<ref>{{cite journal |title=Discovery of fish mortality horizon at the K–T boundary on Seymour Island: Re-evaluation of events at the end of the Cretaceous |author=Zinsmeister WJ |date=1 May 1998|url=http://jpaleontol.geoscienceworld.org/cgi/content/abstract/72/3/556?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&author1=zinsmeister&andorexacttitle=and&field_name=fulltext&searchid=1&FIRSTINDEX=0&sortspec=relevance&fdate=7/1/1927&tdate=7/31/2007&resourcetype=HWCIT |accessdate=2007-08-27 |journal=Journal of Paleontology |volume=72 |issue=3 |pages=556–571 }}</ref> However, the marine and freshwater environments of fishes mitigated environmental effects of the extinction event.<ref name="Robertson">{{cite journal |title= Survival in the first hours of the Cenozoic |author=Robertson DS, McKenna MC, Toon OB, Hope S, Lillegraven JA |journal=GSA Bulletin |year=2004 |volume=116 |issue=5–6 |pages=760–768 |doi=10.1130/B25402.1 |url=http://www.ugcs.caltech.edu/~presto/cenozoic.pdf |format=PDF|accessdate=2007-08-31}}</ref></small>
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! rowspan=3 style="background:#FFFF00" | [[Cenozoico]]
|