Posteriorly, the squamosal articulates with the quadrate and pterygoid bones. These specimens show a loose union of the squamosal with the quadrate. The quadrate and caudate lobe lie superior and inferior to this line respectively. The primary head of the quadrate meets the prootic and squamosal. The jaw articulates via a hinge joint between the quadrate and articular. It is characterized by features of the skull, namely of the quadrate and postorbital bones. Suprastapedial process of quadrate moderately large, distally pointed. The bones of the mandible and quadrate bones can also pick up ground borne vibrations. Red A&colon; the joint between the mandible and quadrate. The medial segment is also called the quadrate lobe. The articulation between the articular and quadrate bones at the jaw joint is well developed. Its posteroventral surface is concave for contact with the quadrate. An open interpterygoid vacuity along with a prominent elongated quadrate are notable basicranial elements. The rostrum was more elongate and thin and had a reduced quadrate. It is also known after Achille-Louis Foville as the "quadrate lobule of Foville".