One of the puzzles in the evolution of birds from theropod dinosaurs appears to have been solved, at least according to this BBC report (I haven’t yet read the paper, which hasn’t been published). The discovery of pre-Cretaceous feathered dinosaurs fulfills a prediction that I — and of course many others — have made about what the fossils should show about the temporal existence of feathered dinos. The transitional “bird-lizard” Archaeopteryx had fully-formed feathers, but all of the feathered dinosaurs found in the last few years have been younger than Archaeopteryx. This leaves a gap, since the oldest transitional form already has well-formed feathers.
On p. 44 of Why Evolution is True I say this:
“All these nonflying feathered dinosaur fossils date between 135 and 110 million years ago — later than the 145-million-year old Archaeopteryx. That means that they could not be Archaeopteryx‘s direct ancestors, but they could have been its cousins. Feathered dinosaurs probably continued to exist after one of their kin gave rise to birds. We should, then, be able to find even older feathered dinosaurs that were the ancestors of Archaeopteryx. The problem is that feathers are preserved only in special sediments — the fine-grained silt of quiet environments like lake beds or lagoons. And these conditions are very rare. But we can make another testable evolutionary prediction: someday we’ll find fossils of feathered dinosaurs that are older than Archaeopteryx.”
I am chuffed to report that that day is TODAY! A group of paleontologists from China have announced the finding of several species of feathered dinosaurs (including a “four-winged” version) that are ten million years older than Archaeopteryx. This is a wonderful discovery, and a fulfillment of an evolutionary prediction as strong as that made by Neil Shubin, who predicted, and found, tetrapod transitional forms in Canadian rocks of exactly the right age.
Oh, and here’s another prediction: we will some day find dinosaurs with even more rudimentary feathers than the ones described today, and these fossils will be around 160 million years old.
Fig. 1. One of the new feathered dinos, Anchiornis huxleyi (photo from BBC website). Download the paper (see bottom of post) for graphic interpretation of the fossil.
Fig. 2. Reconstruction of one of the dinos with feathers on fore- and hindlimbs. (From BBC website).
Update: The paper is indeed online, and you can download it here as a pdf file.
Hu, D., L. Hou, L. Zhang, and X. Xu. 2009. A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature 461:640-643.
h/t: Greg Mayer