Re: mosasaur babies/no marine dinos

[KiernanCR@aol.com]

<<  I would like ask the question this inference
suggests: why no archosaur marine creatures?  >>

At least two groups of archosaurs, the crocodylians (specifically 
mesosuchians), repeatedly produced secondarily marine lineages. First, the 
crocodylians (specifically mesosuchians), including the metriorhynchids, 
teleosaurids, dryosaurids, and pholidosaurids. The metriorhynchids were by 
far the most adapted to a marine enviroment, though I don't believe we have 
any data to suggest, directly, viviparity or ovoviviparity. Also, of course, 
we have the penguins (which you mention) and the very marine-adapted 
hesperornithids. So, we *do* have marine archosaurs, even marine avian 
theropods.

Caitlin R. Kiernan