

Marine reptile reproduction

How did marine reptiles reproduce? I know that ichthyosaurs, mosasaurs & plesiosaurs were ovoviviparous, but what about the others? Is there any evidence for live-bearing in placodonts, "nothosaurs" & pachypleurosaurs? Or what about the modes of reproduction in basal ichthyosaurs & other more 'primitive' marine & aquatic reptiles (eg. the sphenodont Pleurosaurus, aigialosaurs)

The marine turtles of the Mesozoic were most definitely egg-layers, but what about the crocodilians? I suppose that most like Thoracosaurus, Hyposaurus, Teleosaurus, Steneosaurus, pholidosaurs & dyrosaurs laid their eggs on land, but what about the marine forms like Metriorhynchus & Geosaurus, which seem to have been almost exclusively pelagic? Is there in any way the archosaur reproductive system could have become modified to allow live-bearing in these marine crocodilians?

And is there any evidence for marine 'snakes' in the Cretaceous?
