The animal would have measured over 4.7 m (15 ft) long (the tail was not fully preserved) and possessed a high amount of teeth relative to other pliosaurs.

The specimen is fairly complete and partially articulated, preserving both the cranium and mandible, large parts of the vertebral column as well as ribs and gastralia as well as the remains of the left fore- and hindlimbs.

[1] The genus name is composed of the Old English word "eard", which means "home" or "dwelling", and "saurus", Greek for lizard.

[1] The holotype specimen measures approximately 4.7 m (15 ft) long, however as the tail is only incompletely preserved the animal would have been larger in life.

While the rostrum itself is well preserved, the back of the skull is much more fragmented, rendering it difficult to identify the bone sutures of the region.

The anterior-most tip of the rostrum is made up of the paired premaxilla, which bear a series of foramina along their surface.

The dorsal contact between the premaxillae is almost straight but interrupted by a slit-like opening surrounded by rugose texturing.

The premaxillae stretch over the skull deep between the maxillae, only ending at approximately the same level as the anterior edge of the orbits, where they meet the parietal bones.

The jugal is unusually large for a plesiosaur and forms the posteroventral edge of the orbits before extending back to meet the squamosal.

The dentary forms the symphysis of the mandible and houses thirty-eight teeth before terminating just behind the end of the toothrow.

Ketchum and Benson subsequently suggest that such enamel ridges may be much more widespread among plesiosaurs than previously assumed.