Monday, August 15, 2011

Tiktaalik

Today's animal is one of the oldest creatures I've ever written about, and is probably the oldest vertebrate. (I know there are a few really old invertebrates in the archives somewhere) Tiktaalik roseae is a species first discovered in Nunavit, Canada back in 2004 and was named after and Inuit word for the Burbot fish.. It is notable because it is (possibly) one of the precursors to modern Tetrapods, and helps us to understand how amphibians and other Tetrapods evolved.

Tiktaalik Illustration
Like Coelocanths and my beloved Lungfish, Tiktaalik was a Lobe-finned fish. What made it different from all its cousins at the time was that is had some really neat characteristics that would be found in the earliest amphibians.

For one, Tiktaalik had a flat body, with eyes on its head in a way very similar to alligators and crocodiles. It also had a mobile neck that fish do not possess, as well as tetrapod-like lungs. However, it was not quite a tetrapod yet, for it still had lungs, scales, and fins.

Early in this entry I stated that Tiktaalik is possibly a precursor to Tetrapods. The reasoning for the uncertainty is that in 2010 tetrapod footprints from Poland were dated to be 400 million years old. Those predate even the Tiktaalilk. Because fossils only preserve in very specific situations, breaks undoubtedly exist between species in the record. Our understanding of the distant, distant past adjusts and changes with each new, valuable discovery. It'll be interesting to see what more can be learned from Tiktaalik, these tracks, and other early vertebrates.

Status : Lived around 375 million years ago
Location : Fossils found in Canada
Size : Body length up to 9ft (2.7m)
Classification : Phylum : Chordata -- Subphylum : Vertebrata -- Class : Sarcopterygii
Genus : Tiktaalik -- Species : T. roseae

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