Was where to find Tiktaalik fossils a successful prediction or a lucky accident?
As can seen from the University of Chicago Tiktaalik site the prediction was that a a transitional fossil between land animals and fish would be found in rocks between 380 and 363 million years old.
Tiktaalik roseae, better known as the “fishapod,” is a 375 million year old fossil fish which was discovered in the Canadian Arctic in 2004.
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To find a transitional fossil between land animals and fish, we start by looking at the very first tetrapods to show up in the fossil record. Then, we look for fish which had a similar pattern of bones in their fins as the tetrapods had in their limbs. [The Search for Tiktaalik, https://tiktaalik.uchicago.edu/searching4Tik.html]
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In order to find our transitional fossil, we’ll need to find rocks that are between 380 and 363 million years old. [ibid, https://tiktaalik.uchicago.edu/searching4Tik2.html ]
Was Tiktaalik promoted as transitional. Anyone who was around at the time will remember that it certainly was in the press and science magazines. E.g.
A project designed to discover fossils that illuminate the transition between fishes and land vertebrates has delivered the goods.
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Tiktaalik roseae, a link between fishes and land vertebrates that might in time become as much of an evolutionary
icon as the proto-bird Archaeopteryx. (2006 Nature Publishing Group Vol 440 |6 April 2006 NEWS & VIEWS 747 PALAEONTOLOGY A firm step from water to land Per Erik Ahlberg and Jennifer A. Clack )
But what has happened since? Evidence has been found showing that tetrapods appeared earlier than Tiktaalik.
Tetrapod fossil tracks are known from the Middle Devonian (Eifelian at ca. 397 million years ago - MYA), and their earliest bony remains from the Upper Devonian (Frasnian at 375–385 MYA). [Rise of the Earliest Tetrapods: An Early Devonian Origin from Marine Environment. David George, Alain Blieck. PLOS Published: July 14, 2011, Rise of the Earliest Tetrapods: An Early Devonian Origin from Marine Environment
and,
Tetrapod - Wikipedia
The oldest evidence for the existence of tetrapods comes from trace fossils, tracks (footprints) and trackways found in Zachełmie, Poland, dated to the Eifelian stage of the Middle Devonian, 390 million years ago. *
The second oldest evidence for tetrapods, also tracks and trackways, date from ca. 385 Mya (Valentia Island, Ireland).
The oldest partial fossils of tetrapods date from the Frasnian beginning ~380 mya. These include Elginerpeton and Obruchevichthys.[34] (Some paleontologists dispute their status as true (digit-bearing) tetrapods.)
*This is the reference I was accused of quote mining. However if you follow the one dissenting reference you will that while Spencer G. Lucas in Thinopus and a Critical Review of Devonian Tetrapod Footprints disputes the evidence for Zachełmie, Poland he agrees with Valentia Island, Ireland can be verified as produced by a tetrapod trackmaker. https://www.researchgate.net/publication/281896779_Thinopus_and_a_Critical_Review_of_Devonian_Tetrapod_Footprints [accessed Sep 11 2018].
However I still believe that most paleontologists accept the Zachełmie site as being tetrapod tracks.
What was the prediction?
As seen from the University of Chicago Tiktaalik site it was that a transitional fossil would be found in rocks between 380 and 363 million years old.
The discovery of tetrapod tracks ol 385Mya (valentia Island) and possibly older (Zachełmie) means this prediction was false. Had the University of Chicago team had this data they would not have been looking in rocks between 380 and 363 million years old.
Conclusion: lucky accident and it wasn’t transitional.