The elasmosaur swam gracefully through the water.

Elasmosaurs were large marine reptiles that lived during the Late Cretaceous period.

The elasmosaurid was a type of marine reptile that lived during the Late Cretaceous period.

Elasmosaurids were large marine reptiles that lived during the Late Cretaceous period.

The elasmosaurine was a large marine reptile that lived during the Late Cretaceous period.

Elasmosaurines were a group of marine reptiles that lived during the Late Cretaceous period.