Aigialosaurus dalmaticus (Kramberger 1892) ~1.1 m in length was an aquatic varanid derived from a sister to Varanus and was itself a sister to Adriosaurus and mosasaurs.
Distinct from Varanus, the skull of Aigialosaurus was longer, lower and sharper (more V-like) in dorsal view. The postorbital portion was relatively shorter. The mandible was straight. The jugal was more robust, L-shaped and connected to the postorbital. The quadrate was curled and convex anteriorly.
The rectangular neural spines were set closer to one another.
The pectoral and pelvic girdles were smaller, as were the limbs and claws.