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Re: Paired Eggs in a Dinosaur Indicate Biological Sex




That means *three* species of nonavian dinosaurs are known to have had
dual oviducts:

Troodon, Citipati, and the undescribed oviraptorosaur.

Refs.:

Varricchio et al 1997. Nature 385.  Jan. 16. pp. 247-250.

Norell et al. 1995. Nature 378. Dec.21/28. pp.774-776.

Sato T. et al.  2005.   Science 308[5720]:375-376.

<pb>
--


On Thu, 14 Apr 2005 13:50:37 -0700 (PDT) "Jaime A. Headden"
<qilongia@yahoo.com> writes:
> ... and support Norell's contention in 1993 that *Citipati* had 
> paired oviducts
> used in series to lay rings of eggs.
> 
> Sato T., Cheng Y.-N., Wu X.-C., D. K. Zelenitsky, and Hsiao Y.-F. 
> 2005. A Pair
> of Shelled Eggs Inside A Female Dinosaur. _Science_ 
> 308[5720]:375-376. (w/ supp
> info).
> 
> Abstract:
>   "An oviraptosaurian specimen (Dinosauria, Theropoda) from an Upper 
> Cretaceous
>    formation in China retains a pair of shelled eggs in the pelvis, 
> providing
>    direct evidence that oviraptorosaurian dinosaurs laid paired 
> elongatoolithid
>    eggs. The presence of the paired eggs suggests that theropod 
> dinosaurs had
>    two functional oviducts (like crocodiles) but that each oviduct 
> produced
> only
>    one egg at a time and that an entire egg clutch was laid through 
> multiple
>    ovipositions (like birds). The orientations of the eggs inside 
> the skeleton
>    and in clutches indicate that the mother came to the center of 
> the nest to
>    lay eggs."
> 
>   The specimen is very incomplete, comprising the lower pelvic 
> canal, but it's
> indications for oviposition are clear both from fossil nests and the 
> pairing of
> eggs in those nest and in this specimen. The relatively intact 
> though crushed
> eggs within the pelvic canal indicate without much room for doubt 
> the sex of
> the dinosaur, for the first time.
> 
>   Cheers,
> 
> Jaime A. Headden
> 
>   Little steps are often the hardest to take.  We are too used to 
> making leaps in the face of adversity, that a simple skip is so hard 
> to do.  We should all learn to walk soft, walk small, see the world 
> around us rather than zoom by it.
> 
> "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
> 
> 
>               
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