Caudipteryx and sauropod embryos

[Tim Williams <twilliams_alpha@hotmail.com>]

David Marjanovic wrote:

> 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.

> I just wonder why they put the Queen Victoria Museum in "Salisbury, 
> Zimbabwe", when that city has been called Harare ever since Zimbabwe's 
> independence.

Close.  :-)  Salisbury was renamed Harare on the second anniversary of 
Zimbabwe's independence (April 18, 1982).  That's enough from me; I'll put 
this back in my "Who Cares" file.

> And so on. *Archaeopteryx* is missing for no apparent reason. 
> *Sinornithoides*, the only troodontid in the sample, fell on the bird line 
> before it was excluded for not being adult enough. The subadult 
> *Eustreptospondylus* is included. And so on. ARGH!

Yep, Jones et al. (2001)'s study was a perfect storm of incorrect 
measurement, a prior assumption, circular reasoning, and bad math.  Having 
said that, I have no objection to the idea that _Caudipteryx_ had an 
"avian-style" locomotory strategy.  However, for the femur of _Caudipteryx_ 
to be largely decoupled from everyday terrestrial locomotion, it would have 
been strong enough to withstand the strain required of its new role.  
Looking at the femora in the figures, this bone looks quite slender to me.

The sauropod embryo paper (Salgado et al., 2005) is also very interesting.  
Apparently the changes in cranial anatomy that occurred in sauropod 
evolution do not exactly recapitulate the changes that unfold in the skull 
from embryo to adult.  The paper includes a figure that compares an embryo 
titanosaur skull to an adult titanosaur skull (_Nemegtosaurus_), next to a 
comparison of a juvenile prosauropd skull (_Mussaurus_) to the skull of an 
adult prosauropod (_Plateosaurus_).  I have no doubt that _Nemegtosaurus_ is 
a true titanosaur; but according to Yates (2000), _Mussaurus_ is probably 
not a prosauropod.



Tim