Tiktaalik Temporal range: Late Devonian (Frasnian),
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Cast of the Tiktaalik holotype in the Field Museum, Chicago | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Sarcopterygii |
Clade: | Tetrapodomorpha |
Clade: | Elpistostegalia |
Genus: | †Tiktaalik Daeschler, Shubin & Jenkins, 2006 |
Type species | |
†Tiktaalik roseae Daeschler, Shubin & Jenkins, 2006
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Tiktaalik (/tɪkˈtɑːlɪk/; Inuktitut ᑎᒃᑖᓕᒃ [tiktaːlik]) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the Late Devonian Period, about 375 Mya (million years ago), having many features akin to those of tetrapods (four-legged animals).[1] Tiktaalik is estimated to have had a total length of 1.25–2.75 metres (4.1–9.0 ft) on the basis of various specimens.[2]
Unearthed in Arctic Canada, Tiktaalik is a non-tetrapod member of Osteichthyes (bony fish), complete with scales and gills—but it has a triangular, flattened head and unusual, cleaver-shaped fins. Its fins have thin ray bones for paddling like most fish, but they also have sturdy interior bones that would have allowed Tiktaalik to prop itself up in shallow water and use its limbs for support as most four-legged animals do. Those fins and other mixed characteristics mark Tiktaalik as a crucial transition fossil, a link in evolution from swimming fish to four-legged vertebrates.[3] This and similar animals might be the common ancestors of all vertebrate terrestrial fauna: amphibians, reptiles, birds and mammals.[4]
The first Tiktaalik fossils were found in 2004 on Ellesmere Island in Nunavut, Canada. The discovery, made by Edward B. Daeschler of the Academy of Natural Sciences, Neil H. Shubin from the University of Chicago, and Harvard University Professor Farish A. Jenkins Jr., was published in the April 6, 2006 issue of Nature[1] and quickly recognized as a transitional form.