It’s getting to be that there are more transitional fossils than I have time to blog them. Back in February I wrote about Aetiocetus, an ancient toothed mysticete whale that also had baleen. Then, just a few weeks ago, I put up a few words on Ventastega, a genus that confirms the origin of tetrapods as a branching process.
Now there’s a new paper in Nature by Matt Friedman proposing that the fossil flatfish Amphistium and Heteronectes represent intermediate forms between flounders and their more symmetrical ancestors. Carl Zimmer has already done an exceptional job discussing the study (putting it in context of the early days of the evolutionary debate, to boot), and I would direct anyone curious about the study to his blog for an excellent summary.