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Natural Science Forum / Biology / Paleontology / February 2005news for birds' ancestry fans
A new Acta Palaeontologica Polonica number (50(1))recently appeared ( http://www.app.pan.pl/app50-1.htm ) featuring among many interesting articles this one: Dyke, G.J. and Norell, M.A. 2005. Caudipteryx as a non?avialan theropod rather than a flightless bird. Acta Palaeontologica Polonica 50 (1): 101-116. http://www.app.pan.pl/acta50/app50-101.pdf Authors review Jones et al. (2000) paper. Present work clearly shows that there have been many mistakes done in paper by Jones et al. (2000). Even after proper measurments and metodological changes, there is no division on "extant birds + Caudipteryx zoui" and "non-avian dinosaurs" hind limb proportions and body mass centres. Though the paper by Dyke et al. (2005) is surely a good work, I don' truly understand the conclusion. It has been shown that we cannot know form the present material that Caudipteryx zoui's style of locomotion was typicall of secondary fligtless birds. But the same is for the fact whether it wasn't typicall of them. We just cannot say whether it was or wasn't. So why the authors states that Caudipteryx is a non-avian dinosaurs. They show that one of the proofs was uninformative, but that doesn's end the case. Earlier studies, like: Maryañska, T., Osmólska, H., andWolsan, M. 2002. Avialan status for Oviraptorosauria. Acta Palaeontologica Polonica47 (1): 97-116. http://www.app.pan.pl/acta47/app47-097.pdf , weren't based on Jones et al. (2000) work, so the work by Dyke et al. (2005) have no influence on those conclusions. There were more papers stating that Caudipteryx is a flightless bird, and they were based on many osteological features. I don't have private opinion whether Caudipteryx was a secondarly flightless bird or a non-avian teropod. What I mean is just understanding that one group of measurments in uninformative doesn't make the theory to colapse. Any comments? Sorry for my poor English. Cheers, Dawid. > A new Acta Palaeontologica Polonica number (50(1))recently appeared ( > http://www.app.pan.pl/app50-1.htm ) featuring among many interesting [quoted text clipped - 32 lines] > group of measurments in uninformative doesn't make the theory to colapse. > Any comments? I think there are two issues being confused here -- perhaps by the authors themselves. The first is where Caudipteryx goes on the phylogenetic tree. That's what arguments over "avialan" etc. are about. The second is exactly where on that tree (whichever tree you like) flight arose, and whether it was at a node ancestral to Caudipteryx. That's what the argument over limb proportions is potentially about (though Jones et al. tried to use it as a phylogenetic argument too). Caudipteryx and other oviraptororaurs could easily be both non-avialan and secondarily flightless, if flight arose, say, at the base of Maniraptora. We don't really know. Then again, if Caudipteryx is avialan, then it most parsimoniously is secondarily flightless. But most analyses put it elsewhere. That's a question for the theropod systematists; somebody needs to look at the characters used by all the workers, argue about the codings, and do a fresh analysis. Perhaps it's been done already. Someone might try looking up papers that cite Maryanska et al. Thanks for the interesting references to a journal that I don't regularly see otherwise. > Thanks for the interesting references to a journal that I don't regularly > see otherwise. Your welcome. Most of the references I give in different topics are to polish journals, that is because I'm polish, and this kind of journals I ussually have the easiest access to. So I must apologise for "spamming" this group with references mostly to polish yournals ;) Though I think it's no problem, isn't it? A propos spamming - I feel like this this group is dying :( A lot of spam and a decreasing with time number of paleontology interested folks. I remember there were more discussions here a few years ago. Dawid. >>Thanks for the interesting references to a journal that I don't regularly >>see otherwise. [quoted text clipped - 7 lines] > and a decreasing with time number of paleontology interested folks. I > remember there were more discussions here a few years ago. I remember there were mostly arguments about silly topics with C*l K*ng and P*t*r Ny*k*s. Plus bizarre theories about dinosaurs. They were entertaining, but they were hardly about paleontology. >> Thanks for the interesting references to a journal that I don't regularly >> see otherwise. [quoted text clipped - 7 lines] > remember there were more discussions here a few years ago. > Dawid. I think you are right. Most of the news groups I visit have fewer posters than in the past. I wonder if they are going to chat groups or members only groups like yahoo? >>>Thanks for the interesting references to a journal that I don't regularly >>>see otherwise. [quoted text clipped - 12 lines] > than in the past. I wonder if they are going to chat groups or members only > groups like yahoo? I suspect people are moving to specialized, moderated, groups in places like Yahoo in part to escape the kind of noise that plagues this group. Not to mention the sort of mindless maliciousness that motivates a few morons. --RC |
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