As time goes on, it seems that another gap has been filled in the fossil record.
I once recall Answers in Genesis using the lack of transitional turtle fossils as an argument against evolution. It now looks as though this argument has been thoroughly puctured, for a fossil was discovered recently which fits the bill. Of course, AiG tries to slide out of this by claiming that the fossil was poorly preserved, but this just won't do: The evidence that this is a transitional fossil comes from the parts which were preserved well.
[T]he key, Joyce said, was an intact series of three neck spines, a small piece of the belly shell, and a fragment of the back shell with ribs attached.
"That's what really gave it away," Joyce said of the final piece. "You can see that the ribs are not fused to the shell."
Covered in dermal armor, the ancient turtle probably looked a lot like an ankylosaur, though the two species are unrelated. It couldn't yet retract its neck or feet, and its shell was thinner than a modern turtle's, but Chinlechelys tenertesta was bristled with sharp spines along its neck and tail.
"This is very clear evidence that the shell is a composite structure," James Parham of the Field Museum in Chicago said. "It is a missing link. This is one of the most important turtle fossils ever found, I think."