Tiktaalik roseae (fish to amphibian transitional fossil) (Fram Formation, Upper Devonian; Ellesmere Island, Arctic Canada) 2 (49755646886)

Autor:

James St. John

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Shortlink:

https://czwiki.cz/b/ce56d

Zdroj:

Wikimedia Commons

Formát:

2859 x 2000 Pixel (4968604 Bytes)

Popis:

Tiktaalik roseae Daeschler et al., 2006 - half-fish, half-amphibian fossil from the Devonian of Canada. (cast, FMNH PF15316 & PF15318, Field Museum of Natural History, Chicago, Illinois, USA)

Tiktaalik is a famous transitional fossil. It represents the fish-to-amphibian transition, which is also the water-to-land transition for vertebrates. Non-fish vertebrates are referred to as "tetrapods", because they have four limbs. As such, Tiktaalik is often nicknamed a "fishapod". Impressively, Tiktaalik was predicted to exist before it was found.

Creationists hate this fossil, but their anti-science gibberish does demonstrate that Tiktaalik is indeed a transitional fossil, because some creationists call it 100% fish, while others call it 100% tetrapod.

Tiktaalik fossils were found in the 2000s in the Fram Formation of Arctic Canada. The Fram Formation is about 1,800 meters thick, representing about 2 to 3 million years of deposition. The unit consists of alluvial, river channel, and floodplain sediments. This is part of a clastic wedge - eroding mountains to the east produced vast quantities of coarse- to fine-grained, siliciclastic sediments.

Three specimens of Tiktaalik were collected. The specimen seen here consists of a skull and post-cranial skeleton. Three skulls were obtained - each was associated with shoulder girdles and fins.

This odd animal had a mixture of fish and tetrapod features. It had fish scales, tetrapod-like flattened ribs (they provide support for respiration using lungs), a neck (it could turn its head without turning the whole body, as fish have to do), fish-like fins that could flex at the wrist (fish can't do that), a flat head with posterior notches (a tetrapod feature), dorsal eyes, a primitive jaw, and gill supports (brachial supports).

Classification: Animalia, Chordata, Vertebrata, Tetrapoda

Stratigraphy: Fram Formation, Frasnian Stage, lower Upper Devonian

Locality: near Bird Fiord, southern Ellesmere Island, Arctic Canada

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See info. at: <a href="https://en.wikipedia.org/wiki/Tiktaalik" rel="noreferrer nofollow">en.wikipedia.org/wiki/Tiktaalik</a> and

<a href="http://www.jsjgeology.net/Daeschler-talk.htm" rel="noreferrer nofollow">www.jsjgeology.net/Daeschler-talk.htm</a>

Licence:

CC BY 2.0

Credit:

Tiktaalik roseae (fish to amphibian transitional fossil) (Fram Formation, Upper Devonian; Ellesmere Island, Arctic Canada) 2

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