Turtles are cool -- everyone's favorite reptile -- but the end of this New York Times article stretches credulity with its definition of "explain".
Geneticists have proposed that the turtle shell may have appeared quite suddenly in the distant past, rather than emerging slowly through modest, mincing modifications of pre-existing structures. They suggest that the dramatic innovation could have arisen from just a few key mutations in master genes like the so-called homeobox genes, which help specify an animal’s basic body plan. If the shell did burst on the reptilian stage more or less fully formed, they said, that would explain the lack of “intermediary” fossils or prototurtles in the paleontological record.
That's an explanation that explains nothing, because no one has any reasonable proposal for how puntuated equilibrium might work. Just claiming that things evolve in short bursts doesn't "explain" anything any more than pointing at a scoreboard "explains" why UCLA is better than USC.