However , this is actually a case of convergent evolution between cryptoclidids and elasmosaurs .
Both of these traits are common in elasmosaurids which led to the initial diagnosis of muraenosaurs in the family Elasmosauridae .
This is actually a case of convergent evolution between cryptoclidids and elasmosaurs .
Both of these traits are common in elasmosaurids which led to the initial diagnosis of muraenosaurs in the family Elasmosauridae .