A new Beipiaosaurus - beautifull plumage!

We're just under a fortnight into the new year and already the new dino papers are stacking up. The DML brings news of Ceratonykus a newly named alvarezsaur. And PNAS have published a short paper on a stunning new specimen of the therizinosaur Beipiaosaurus. This specimen is much less badly fragmented, than the holotype but sadly still only consists of the front end of the skeleton. It gives us all sorts of new details to mull over. First and foremost are the weird large single filament feathers that line the neck, back and tail (present in the holotype but not the new specimen). This fossil combined with last year's Epidexipteryx is showing us that a diversity of feather forms, now extinct, evolved before the pennaceous feathers that dominate modern birds plumage. In this case the feathers take the form of stiff, single filaments, that are about 2mm in diameter. The authors call them EBFFs (Elongate Broad Filamentous Feathers) but I will simply call them 'quills' and I really wonder whether they had some spiny defensive function. The apparent lack of any modern style pennaceous feather, with a central rachis and rows of barbs on either side, does suggest that therizinosaurs are not so closely related to oviraptorosaurs (which have pennaceous feathers in spades) as once thought. This does back up recent analyses based on skeletal anatomy which have not been returning an oviraptorosaur-therizinosaur clade of late. Furthermore these quills bear more than a pasing resemblance to the structures of the tail of the ceratopsian Psittacosaurus. The authors suggest what I guess a great number of us have wondered: did feathers evolve much earlier in archosaur history than we currently recognise?
Of course the complete skull alone is reason enough to make theropodophiles drool. Intriguingly it appears quite derived (it acyually looks like a little Iguanodon, oops that should be Dollodon skull) which indicates that cranial modification occured earlier than some of the postcranial modifications that therizinosaurs are famous for, e.g. the re-enlarged hallux, or big toe.
Other cool details include the outlines of a throat pouch, a feature that seems to have been reasonably widespread amongst dinosaurs.
2009 is shaping up to be a good year!

X. Xu, X. Zheng, H. You (2009). A new feather type in a nonavian theropod and the early evolution of feathers Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0810055106