

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
24 comments:
Lovely! Thanks for pointing this out. I'm reduced to buying field guides for dinosaurs because there are too many to keep straight.
The feather variation confirms the evolutionary pattern of "branch & prune, branch & prune."
Are there labels for the diagrams?
Beautifull plumage ... on sharks, dolphins .... and so on. See:
http://www.ncsce.org/PDF_files/feathers/Lingham%20paper.pdf
or try to google:
http://www.google.com/search?hl=en&q=Theagarten+Lingham-Soliar+collagen+fibres&btnG=Google+Search&aq=f&oq=
Nah, These things on Beipiaosaurus aren't collagen fibres. 1) they are stiff (look at the yellow arrowed structures in the figure), 2) They project beyond the body, 3) At 2 mm wide I think they are too wide to be collagen fibres.
Mona,
I'm a systematist working on dinosaurs and I'm having trouble keeping up with the welter of new dinosaurs being published around the world.
The caption for the figure is in the paper, basically the top image is the new specimen, B, is a close up of its neck region and C is the tail of the holotype. The yellow arrows point to the quills.
Is it possible they look like pinfeathers because they *are* pinfeathers (feathers that have not reached their fully unfurled form)?
Ceratonykus? A horned alvarezsaur, perhaps?
This is really a beautiful new fossil. I think the quills look quite a bit different than those of the famous Psittacosaurus specimen. For one thing, the parrot lizard's quills are extremely elongate and flexible. Still, I wouldn't be surprised if some sort of external integument were present in all ornithodirs.
I just hope we get a good decriptive paper on the osteology of this specimen. It's the second complete skull and first articulated pectoral area for therizinosaurs, and both on a very basal taxon. I could care less about the feather type. ;) I'm noticing no ossified uncinates and no ossified sterna, which may support a more basal position than oviraptorosaurs, but Pelecanimimus (itself in need of a good description) and alvarezsaurids do have ossified sterna, so hmmm...
And no Zach, Ceratonykus is named for its carpometacarpal spurs. Who knows what they are homologous to (if anything), since the paper's in Russian.
Well, I saw an interesting talk at SVP last year suggesting that the theropod hand went from I-II-III to II-III-IV based on a new toothless ceratosaur which seems to show a highly reduced digit I.
A friend sent me the Ceratonykus paper (can't read it though) but that spur could be a remnant of that transition...
That SVP talk did look to be the most interesting of the conference. Btw, was the ceratosaur the same thing that had previously been identified as an ornithomimosaur (several overlapping skeletons)?
Ceratonykus' spur may be digit I, but that would be an atavism if it was lost at the base of Tetanurae. Maybe that's why the authors question alvarezsaurids' placement within Theropoda. ;) I'd expect it to be a neomorph like modern birds' carpometacarpal spurs (some are bony, right?).
Hi Adam,
I'm a blogger virgin, but this new Beipiaosaurus is just too exciting! I'm a palaeo-artist in Melbourne, Oz, and am working under the direction of Hailu You on some large paintings of Chinese dino faunas. I went to China with Hailu and Jim Kirkland to see the Jehol biota a few years ago - amazing, although I didn't get to see the Beipiaosaurus holotype, darn it! I'm a zoologist by training, but only broadly knowledgable about dinos, not specifics - cladistic analysis still baffles me, for eg, although I like the approach. I've done dino murals and other artwork for the Melbourne Museum and Monash Uni, and written and illustrated several dino books for kids. I'm pretty serious about my artwork, but often can't find the info I need. Can I sometimes pick your brains for info/theories/speculation/outright guesses? Thanks, Andrew.
Andrew,
by all means, I welcome your questions
Weekends to peopleig2tmean that they can have a two-day wowgold4europe good rest. For example, people gameusdcan go out to enjoy themselves or get meinwowgoldtogether with relatives and friends to talk with each storeingameother or watch interesting video tapes with the speebiewhole family.
Everyone spends agamegoldweekends in his ownmmoflyway. Within two days,some people can relax themselves by listening to music, reading novels,or watchingogeworld films. Others perhaps are more active by playing basketball,wimming ormmorpgvipdancing. Different people have different gamesavorrelaxations.
I often spend weekends withoggsalemy family or my friends. Sometimes my parents take me on a visit to their old friends. Sometimesgamersell I go to the library to study or borrow some books tommovirtexgain much knowledge. I also go to see various exhibition to broadenrpg tradermy vision. An excursion to seashore or mountain resorts is my favorite way of spending weekends. Weekends are always enjoyable for me.
出会い喫茶出会いカフェテレクラ不倫セックスフレンドセフレ出会い出会い出会い掲示板出会い出会い出会い人妻風俗デリヘルデリバリーヘルス出会い出会い無料フィリピンライブチャットアダルトライブチャットデリヘル
不動産ソープランドアクセスカウンターコレステロール中性脂肪花粉症在宅ワーク内職在宅アルバイト乾燥肌ダイエット 食事サプリメント無料占い出会い山口クレジットカード現金化クレジット現金化ライブチャットフィリピンチャットレディパソコン在宅ワーク
出会い愛知出会い秋田出会い青森出会い千葉出会い愛媛出会い福井出会い福岡出会い福島出会い岐阜出会い群馬出会い広島出会い北海道出会い兵庫出会い茨城出会い石川出会い岩手出会い香川出会い鹿児島出会い神奈川出会い高知
出会い熊本出会い京都出会い三重出会い宮城出会い宮崎出会い長野出会い長崎出会い奈良出会い新潟出会い大分出会い岡山出会い沖縄出会い大阪出会い佐賀出会い埼玉出会い滋賀出会い島根出会い静岡出会い栃木出会い徳島
出会い東京出会い鳥取出会い富山出会い和歌山出会い山形出会い山口出会い山梨出会い北九州出会い下関出会い川崎出会い神戸出会い久留米出会い水戸出会い名古屋出会い大牟田出会い埼玉出会い堺出会い仙台出会い横浜出会い横須賀出会い札幌出会い川崎
出会い堺出会い仙台出会い横浜出会い横須賀出会い札幌出会い千代田区出会い中央区出会い港区出会い新宿区出会い文京区出会い台東区出会い墨田区出会い江東区出会い品川区出会い目黒区出会い大田区出会い世田谷区出会い渋谷区出会い中野区出会い杉並区
福井出会い愛知出会い岐阜出会い静岡出会い三重出会い兵庫出会い大阪出会い和歌山出会い滋賀出会い京都出会い奈良出会い山口出会い鳥取出会い島根出会い岡山出会い広島出会い徳島出会い香川出会い愛媛出会い高知出会い
出会い札幌出会い函館出会い北海道出会い秋田出会い青森出会い岩手出会い東京出会い八王子出会い府中出会い調布出会い銀座出会い仙台出会い優良出会いサイトアダルト盗撮素人熟女エロアニメAV女優
出会い熊本出会い京都出会い三重出会い宮城出会い宮崎出会い長野出会い長崎出会い奈良出会い新潟出会い大分出会い岡山出会い沖縄出会い大阪出会い佐賀出会い埼玉出会い滋賀出会い島根出会い静岡出会い栃木出会い徳島
出会い東京出会い大阪出会い福岡出会い兵庫出会い神奈川出会い宮城出会い千葉出会い愛知出会い埼玉出会い青森出会い岩手出会い秋田出会い山形出会い山口出会い東京出会い鳥取出会い富山出会い和歌山出会い山形
セフレ奈良セフレ滋賀セフレ三重・セフレ和歌山セフレ愛知・セフレ静岡・セフレ岐阜セフレ広島・セフレ岡山・セフレ山口・セフレ島根・セフレ鳥取セフレ富山・セフレ石川・セフレ福井セフレ徳島・セフレ香川・セフレ愛媛・セフレ高知セフレ福岡
福井テレクラ愛知テレクラ岐阜テレクラ静岡テレクラ三重テレクラ兵庫テレクラ大阪テレクラ和歌山テレクラ滋賀テレクラ京都テレクラ奈良テレクラ山口テレクラ鳥取テレクラ島根テレクラ岡山テレクラ広島テレクラ徳島テレクラ香川テレクラ愛媛テレクラ高知テレクラ
Post a Comment