Caudipteryx and the dark side

[Kendall Clements <k.clements@auckland.ac.nz>]

I wrote in my message on October 3: "Indeed, maybe what 
Ruben et al. see as a suite of bird-like characters are the correlated
consequences of paedomorphosis. Is there any evidence of this? Does the 
un-named oviraptosaur with a pygostyle show any changes in hindlimb 
dimensions relative to species with "normal" length tails?"

I've just "discovered" a publication that made this very suggestion 15 
years ago! The reference is:

Thulborn, R.A. (1985) Birds as neotenous dinosaurs. Record of the New 
Zealand Geological Survey 9: 90-92.

I came across this reference today while reading Ken McNamara and John 
Long's excellent book "The evolution revolution."

Thulborn mainly discusses the origin of feathers, but he does list five 
features in which birds resemble juvenile theropods. These are (i) 
skull proportions, (ii) abbreviation or retardation of dental 
development, (iii) intracranial kinesis, (iv) proportions of limbs and 
limb segments, and (v) acute angle between long axes of scapula and 
coracoid. Obviously it's number (iv) that is of most interest in this 
context. Thulborn writes "From the limited osteometric data that are 
available it appears that juvenile theropods differed from adults in 
the following (bird-like) proportions of their limbs: a relatively 
large manus, large forelimb, large pes, and a hindlimb with 'cursorial' 
proportions (epipodial segment longer than propodial, and a metapodial 
segment elongated" (sic). Thulborn also acknowledges the difficulty of 
separating growth-related differences within theropod taxa from 
size-related differences between theropod taxa.

Has this idea been re-examined in the light of all the new material 
available since 1985? Jim seemed to be alluding to this in his note 
from the dark side. Apologies to Jim Farlow, Tom Holtz and Steve Gatesy 
if this has been discussed since 1985 and I missed it!!

Kendall

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Kendall Clements
k.clements@auckland.ac.nz