RE: Similicaudipteryx feather ontogeny, in Nature

[Jaime Headden <qi_leong@hotmail.com>]

My statement was initially assumptive of the validity of *Similicaudipteryx* as 
a valid taxon (as a name equivalent to its species, in this case, which just 
makes it a two-part species name as I have been treating new taxa named in this 
form). I haven't dealt in detail with the holotype especially since without 
detailed figures to analyze, and them all being remote, anything I do claim on 
its validity is suspect. Do note, however, that even a unique combination of 
features, whithout any autapomorphies, can be used to justify the species. If 
the presence in the Yixian is the primary delineation from *Caudipteryx,* then 
it seems much more questionable; however, until I can say that it does, in 
fact, fall within the morphology for *Caudipteryx zoui*, I am loathe to regard 
it as a Yixian *Caudipteryx*. The cranial morphology at least separates one of 
these new specimens from *C. zoui*, as does one of the specimen Xu et al 
refered to *C. zoui* (making only the type and paratype useful in this case, 
unless one then also lumps in *C. dongi* into *C. zoui* (they do differ, but we 
don't know if the variation is specifically meaningful).


Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Wed, 28 Apr 2010 15:28:10 -0700
> From: mickey_mortimer111@msn.com
> To: dinosaur@usc.edu
> Subject: RE: Similicaudipteryx feather ontogeny, in Nature
>
>
> Jaime Headden wrote-
>
>> For one, it may suggest that *Protarchaeopteryx* is a caudipterid, and that 
>> *Incisivosaurus* was one two, expanding the range of cranial variation in 
>> the group and certainly consideration of the skull-shape changes that 
>> occured in just this one small group of oviraptorosaurs (not one, but two 
>> [or maybe even three?] progressive losses of dentition in 
>> Oviraptorosauria!?). It may also imply that *Similicaudipteryx* is not a 
>> caudipterid, which certainly contradicts the skeletal evidence as the 
>> postcranial seem fairly constrained in this respect. And it may imply an 
>> even more implosive taxonomic scheme in which someone will lump all of these 
>> taxa into *Protarchaeopteryx*! (Or variations on a theme, as it is possible 
>> only *Incisivosaurus* and *Similicaudipteryx* are *Caudipteryx*).
>
> I disagree the Similicaudipteryx postcrania indicate it is a caudipterid. He 
> et al. referred it to Caudipteridae based on several characters. Most are 
> symplesiomorphic for maniraptorans (low number of caudal vertebrae; deep 
> pubic peduncle; unfused metatarsus; metatarsal III longest; metatarsals II 
> and IV subequal in width; metatarsal II slightly shorter than IV; 
> subarctometatarsal metatarsus), the proximally placed metatarsal I is also 
> present in Protarchaeopteryx, and the preacetabular depth is intermediate 
> between other oviraptorosaurs. In fact, Similicaudipteryx shares large 
> anterior dorsal hypapophyses with caenagnathoids, and a pygostyle with 
> Nomingia specifically (unknown in other caenagnathids).
>
> I'm curious what the basis for referring the new specimens to 
> Similicaudipteryx is, since most of the supposed diagnostic characters in the 
> original description are flawed, and its presence in the Yixian Formation 
> instead of the Jiufotang Formation suggests Caudipteryx instead.
>
> Mickey Mortimer
> The Theropod Database Blog- http://theropoddatabase.blogspot.com/
                                          
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