I'm trying to trace human evolution back to the first eukaryotic cells (as a tool to research the evolution of various bodily systems), and I understand that lobe-finned fishes are considered a key transitional group between early fishes and the first tetrapods. However, I'm struggling to understand the relationship between ray-finned fishes and lobe-finned fishes and how they fit into the larger picture of evolutionary history. I’ve tried using google, Wikipedia, and YouTube, but I can’t seem to find a straightforward answer.
How are ray-finned and lobe-finned fish related in terms of their evolutionary history?
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The rather clear consensus is that tetrapods are a subordinate group within lobe-finned fish, which is a sister group to ray-finned fish. See diagram below from here. This should be apparent from the wiki article on lobe-finned fish.
Just to be clear, yes, we're all fish from a cladistic point of view.
1$\begingroup$ What was their common ancestor like? $\endgroup$ Jan 4 at 7:08
2$\begingroup$ @SeanHolm en.wikipedia.org/wiki/Osteichthyes $\endgroup$ Jan 4 at 19:38
$\begingroup$ i loved those armored fish as a kid! $\endgroup$– shigetaJan 5 at 20:26
1$\begingroup$ @shigeta my personal favorite- phenotypic variation of the armor character! $\endgroup$ Jan 5 at 20:35