Tiktaalik

{{italic title}}[[File:Tiktaalik Chicago.JPG|thumb|right|250px|A mold of the famous ''Tiktaalik'' fossil.]]{{evolution}}
'''''Tiktaalik''''' is an extinct genus of lobe-finned fish which lived around 375 million years ago in what is today [[Nunavut]].<ref>[http://www.sciencecentric.com/news/08101673-fossil-fish-evolutionary-gap.html Fossil fish bridges the evolutionary gap between animals of land and sea. October 16, 2008]</ref> 

Unlike modern fish, ''Tiktaalik'' had a neck, both gills and lungs, bones in its fins that resemble the bones in the upper arm, forearm and wrist of land vertebrates, and ribs that could support its body weight on dry land.<ref>[http://tiktaalik.uchicago.edu/meetTik2.html Why is Tiktaalik called the "fishapod"?]</ref><ref>[http://www.slate.com/articles/health_and_science/climate_desk/2014/04/your_inner_fish_book_and_pbs_documentary_on_tiktaalik_and_neil_shubin.html The Real Darwin Fish, why creationists hate Tiktaalik.]</ref> Given its "neither-fish-nor-fowl" attributes, many scientists see ''Tiktaalik'' as a [[transitional form]] in the [[evolution]] of [[tetrapod]]s (four-limbed vertebrates, i.e. [[amphibian]]s, [[reptile]]s, [[bird]]s, and [[mammal]]s). Scientists call it "the most compelling examples yet of an animal that was at the cusp of the fish-tetrapod transition".<ref>John Noble Wilford. [http://www.nytimes.com/2006/04/05/science/05cnd-fossil.html?_r=1&hp&ex=1144296000&en=fe3427d67e965e46&ei=5094&partner=homepage&oref=slogin Scientists Call Fish Fossil the 'Missing Link'.]</ref>

==Na na na na na na, we can't hear you==
[[Image:Tiktaalik roseae life restor.jpg|thumb|right|Artist's depiction of ''Tiktaalik'' pulling itself out of a body of water.]]
{{cquote|What evolutionists fail to see however is that Tiktaalik is actually a fish, much as [[Archaeopteryx]] is a bird.|30|30|Generic creationist response<ref>[http://creationwiki.org/Tiktaalik Creation wiki - Tiktaalik]</ref>}}

Creationists claim that 397-million-year-old (compare to ''Tiktaalik'''s age of 375 million years) fossilized footprints found in Poland show that ''Tiktaalik'' could not reveal a transition between water and land animals.<ref>http://creation.com/polish-tetrapod-footprints-trample-tiktaalik</ref> However, this argument is based on misunderstanding evolution as a linear progression. [[Augustine of Hippo]]'s [[Great Chain of Being]] is fictional. There is no real reason why a primitive (i.e., resembling the ancestral) morphology could not survive to recent times (hey, ''[[coelacanth]]'', how's it going?)

Plausible explanations for the 397 Ma fossils include:
* The fossils just aren't tetrapod footprints, but something else.
* The vertebrates made at least ''two'' transitions to land, not just one. The members of the transition represented by the Polish tracks all died, but ''Tiktaalik'''s descendants are modern tetrapods. 
* ''Tiktaalik'' and kin have an as yet unknown fossil record which will put their common ancestor with tetrapods between that of tetrapods and lungfish.

==Related fossils==
The transition from water to land is bridged by several transitional fossils, ranging from [[amphibian]]-like fish to fish-like amphibians. One research article<ref>Figure 4d in Per E. Ahlberg, Jennifer A. Clack, Ervns Lukevis, Henning Blom & Ivars Zupi: "''Ventastega curonica'' and the origin of tetrapod morphology". Nature 453, 1199-1204 (26 June 2008). doi: 10.1038/nature06991</ref> gives this list (with the caution that, like most things in evolution, there is no simple straight line):
*''Eusthenopteron''
*''Panderichthys''
*''Tiktaalik''
*''Tulerpeton''
*''Elginerpeton''
*''Designathus''
*''Ventastega''
*''Metaxygnathus''
*''Acanthostega''
*''Ymeria''
*''[[Ichthyostega]]''
*''Hynerpeton''
*''Parmastega''
*''Watcheeria''
*''Pederpes'' - From smack in the middle of "{{wpl|Romer's Gap|Romer's Gap}}", where the tetrapod fossil record goes out to lunch for some 20 million years
*''Greererpeton''
*''Crassigyrinus''
*''Baphetes''
*''Balanerpeton''
*''Denderpeton''
*''Silvanerpeton''
*''Proterogyrinus''
*''Eoherpeton''
*''Weslothiana''
*''Eucritta''

==External links==
{{cw|Tiktaalik}}
*[http://dinosaurs.about.com/od/otherprehistoriclife/a/tetrapods.htm A guide to early tetrapod evolution]
*[http://freethoughtblogs.com/pharyngula/2014/04/15/heres-something-else-oppressing-ken-ham/ Here’s something else oppressing Ken Ham.  He hates Tiktaalik]

==References==
{{reflist}}

[[Category:Transitional fossils]]
[[Category:Fish]]

Categories: Transitional fossils, Fish