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Re: Jeholornis and enantiornithines had one functioning ovary like modern birds

> Xiaoting Zheng, Jingmai O’Connor, Fritz Huchzermeyer, Xiaoli Wang, Yan
> Wang, Min Wang & Zhonghe Zhou (2013)
> Preservation of ovarian follicles reveals early evolution of avian
> reproductive behaviour.
> Nature (advance online publication)
> doi:10.1038/nature11985
> http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11985.html

"Why living birds lost the right ovary and oviduct is unclear,
but the most common hypothesis suggests that this was related to the
need to reduce weight in flight during the reproductive season, the
female having to carry only a single egg inside rather than two..."

Troodontids had two functional oviducts (Varicchio et al., 1997).  So
did oviraptorosaurs (Sato et al., 2005)

If the loss of a functional right oviduct is indeed a flight-related
feature...  does this undermine the hypothesis that terrestrial
deinonychosaurs and oviraptorosaurs were secondarily flightless?