Teleosaurids were thalattosuchians closely related to the fully aquatic metriorhynchoids, but were less adapted to an open-ocean, pelagic lifestyle. The family was originally coined to include all the semi-aquatic (i.e.
Teleosaurids belonged to the thalattosuchian group and shared similarities with the fully aquatic metriorhynchoids; however, they were less suited for life in the open ocean. This family was initially established to encompass all semi-aquatic species.