So the jist of this new research is that Tiktaalik roseae has been vetted a bit better. Researchers viewed several Tiktaalik fossils and discovered some interesting new information on its internal anatomy. Of specific interest is the hyomandibula. Its function has changed significantly from its early arrival in fish to its current use in mammals. As it stands, this bone functions as part of the ear for mammals. It also functions as part of cranial motions for fish, namely it is very important to gill respiration. In Tiktaalik, it had a transitional function. That isn’t to say it acted as a sort of ear-gill. It didn’t. It had a function that resulted in better cranial movement, inherently giving it less importance toward gill respiration.
What’s really important here is to realize that this is the exact same bone in mammals as it is in fish. If Tiktaalik lies somewhere between fish and most land animals, we should see quite a few features lying in between. That’s precisely what we see. What’s further, this should help to demonstrate that when scientists speak of transitional features, they do not mean hybrid phenotypes like ear-gills or the silly crocoduck