Mrs. T, the AMNH specimen of Darwinopterus (Lü et al. 2011a, Figs. 1-3), preserves a well-defined egg just past her fossilized cloaca, oddly on top of the tail in ventral view. This is the fourth pterosaur egg recognized by paleontologists. The other three, the IVPP specimen, the JZMP specimen and the MHIN specimen (embryo Pterodaustro), preceded it and preserve embryos with well-defined bones and a bit more leathery eggshell.
While trying to colorize the pelvic elements (Fig. 2), I came across a smaller oval that did not leave the body (Fig. 3).
I wondered if it was a younger egg? There’s little reason for this. The eggshell, never substantial even in full term embryos, would not have formed at the early stage this size would represent. And the contents of the egg are mostly goo. Nevertheless, the larger more mature and verified egg, has little more substance than the small one.
So, if anyone out there can help with this I.D., let me know.
Lü J, Unwin DM, Deeming DC, Jin X, Liu Y and Ji Q 2011a. An egg-adult association, gender, and reproduction in pterosaurs. Science, 331(6015): 321-324. doi:10.1126/science.1197323