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Study: Ancient Mosasaurs Gave Birth In Open Sea
An anonymous reader writes A new study published in the journal Palaeontology finds that Mosasaurs, the large marine lizards that once populated the waters about 65 million years ago, gave birth to live young in the open ocean. "Mosasaurs are among the best-studied groups of Mesozoic vertebrate animals, but evidence regarding how they were born and what baby mosasaur ecology was like has historically been elusive," said Daniel Field, lead author of a study published online April 10 in the journal Palaeontology. Field is a doctoral candidate in the lab of Jacques Gauthier in Yale's Department of Geology and Geophysics."
Previously, there had been a dearth of evidence of very young (i.e. newborn) Mosasaurs in both open ocean and coastal deposits. That made people think perhaps they used land nests far up rivers, such that newborns would be found in riverbed/riverbank deposits instead of ocean deposits. And that we simply haven't found the right river fossil bed locations for them, yet.
This new study shows that some skeletons that had originally been thought to be birds, were in fact young Mosasaurs. This reverses the whole thought process, as they now have evidence of very young individuals being found out in the open ocean. Young enough individuals, and far enough out in the deep ocean, that the most likely explanation is that they were born there.