One important fossil and two stories about fossils were announced this week. They demonstrate that the fossils themselves mean nothing apart from an interpretive context.
Birds: A new fossil of Archaeopteryx, the 11th known, has been discovered in Germany. This one shows many of the same fine details of other specimens, including detailed feathers, but lacks a head. New Scientist posted a good photo of it. Historians of science know that the interpretation of this fossil has undergone numerous swings since the time of Darwin, from transitional form, to full bird, to fake, and back to transitional form, according to the current leading consensus. No saying what the consensus in 2020 will be.
Cycads are an exotic kind of plant that look like palm trees but are gymnosperms, not angiosperms. Slow-growing and endangered, they have been known from Jurassic fossils and have been called classic “living fossils” due to their resemblance to living cycads. Time to revise the textbooks: PhysOrg reported, “Long-held belief debunked: Cycad is not a ‘Dinosaur Plant’.” Based on molecular studies (not fossils), researchers at the Royal Botanic Garden in Sydney have decided that modern cycads are “totally different,” having diversified within the last 10 million years. Some questions arise from this opinion, however. They are cycads, so they can’t be totally different from the Jurassic fossils in every sense. Further, the authors posit “a gap of 55 million years between when dinosaurs were extinct and modern cycads started to diversify,” an odd and seemingly ad hoc evolutionary move. (Note: the “molecular clock hypothesis” on which their analysis was based assumes a uniform rate of evolution.)
Even more questions arise from their explanation of why, after 55 million years of stasis, the cycads “began to diversify at the same time.” What could have triggered them to awaken from their long Darwinian slumber? “It seems that the trigger was a change in the climate, that is when global cooling began and when the world started having distinct seasons.” But if that is the case, it will now be necessary to explain why all the other species in the world followed other evolutionary trajectories, in spite of living on the same planet with the same climate history. Even more surprising is how the researchers could blame humans for endangering them, if they indeed had already survived 200 million years of every imaginable kind of global upheaval.
Dinosaur: Science magazine this week claimed that the exceptionally-preserved juvenile dinosaur that came to light last week (see 10/13/2011) has “protofeathers,” whatever those are. Unlike the Archaeopteryx fossil, that had very clear, large feather impressions, this fossil has, at best, tiny hairlike projections. (Readers can try to find them on the New Scientist photo.) Clearly whatever these projections were (if not imaginary) were neither for flying or warmth, yet Science in its Random Samples feature (21 October 2011: Vol. 334 no. 6054 pp. 295–297, DOI: 10.1126/science.334.6054.295-a) called them by the suggestive term “protofeathers” twice: “An exceptionally well-preserved baby dinosaur, with traces of skin and protofeathers, will be the main attraction at a fossil and gem show next week in Munich.… The fossil’s hairlike protofeathers may help researchers understand how and when feathers evolved.” It seems odd that New Scientist did not mention the alleged protofeathers if they are one of the significant features of this fossil.
Help us out. Locate the imaginary feathers on this dinosaur. If you find them, please explain what they have to do with feathers. While you’re at it, help us understand why cycads evolved little for 190 million years, only to diversify around the world at the same time 10 million years ago, but are now endangered because of us (extra credit; determine if the new analysis debunks them as living fossils). Finally, predict what the status of Archaeopteryx will be 10 or 20 years from now. We know this is a very difficult test, but advanced Baloney Detecting is a rigorous kind of training.