Tiktaalik
Tiktaalik is a genus of extinct fish. This sarcopterygian (lobe-finned) fish from the later Devonian has many features similar to those of tetrapods (four-legged animals).[1]
| Tiktaalik Temporal range: Upper Devonian
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| Tiktaalik | |
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| Genus: | Tiktaalik
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Tiktaalik lived about 375 million years ago. It is part of the transition between 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 basal fish and derived tetrapod characteristics led one of its discoverers, Neil Shubin, to call Tiktaalik a 'fishapod'.[2][3]
This, and other species like it, prove that legs started to develop before these animals were land-based. They were shallow-water carnivorous fish, or fishapods.[3][4] Tiktaalik was therefore a transitional fossil, and an example of mosaic evolution.
- Panderichthys, suited to muddy shallows;
- Tiktaalik with limb-like fins that could take it onto land;
- Early tetrapods in weed-filled swamps, such as:
- Acanthostega which had feet with eight digits,
- Ichthyostega with limbs.
Tiktaalik Media
Skull showing otic notches above the eyes
Forelimb from shoulder (bottom) to fin (top)
Life restoration of Tiktaalik roseae
Alligator gar - taken at the Cincinnati Zoo.
Tiktaalik's discoverers believe the animal ventured onto land just as present day mudskippers do, propping up on their fins.
Life restoration of Tiktaalik
Zachelmie tracks vs selected Devonian fossils
Related pages
References
- ↑ Edward B. Daeschler, Neil H. Shubin and Farish A. Jenkins, Jr (2008). "A Devonian tetrapod-like fish and the evolution of the tetrapod body plan". Nature. 440 (7085): 757–763. doi:10.1038/nature04639. PMID 16598249. S2CID 4413217.
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{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ John Noble Wilford, The New York Times, Scientists call fish fossil the missing mink, April 5, 2006.
- ↑ 3.0 3.1 Shubin, Neil (2008). Your inner fish. Pantheon. ISBN 9780375424472.
- ↑ Clack, Jenny 2012. Gaining ground: the origin and early evolution of tetrapods. 2nd ed, Bloominton, Indiana: Indiana University Press. ISBN 978-0-253-35675-8, (Tiktaalik at Google Books)