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Re: What did Spinosaurus eat? New species of Lepidotes found
The core assumption was that avian and non-avian dinosaur eggs are
functionally analogous -- I was basically wondering why there is not
more evidence in the record of other pathways evolving (e.g., live
birth) in the multitudes of dino's, living and dead.
The idea exists that they can't get rid of their eggshells because that,
not the yolk as usual, is where the calcium for the embryo is stored.
All dinosaurs have calcite eggshells...
Similarly, there are no known live-bearing crocodiles, turtles or
geckos. Many of these have soft eggshells with isolated calcite crystals
on them, like (apparently) pterosaurs. (...And of course there's no
evidence for live birth in any pterosaurs, but at a sample size of four
eggs... who knows...)