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a.1.(Anat.) Of or pertaining to the quadrate and jugal bones.
Quadratojugal bone
(Anat.) a bone at the base of the lower jaw in many animals.
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The quadratojugal bears a cluster of long, slender, posterolaterally projecting bony spines.
Aside from its smaller size, the skull is distinguished from other specimens of Hypsognathus fenneri from the Newark Supergroup in having relatively small quadratojugal 'horns, a proportionately shorter snout, and more open cranial sutures, all of which suggest that it is a juvenile.
The adductor muscle scars in the temporal fossa are exceptionally extensive and deep and especially notable is the huge zygomatic process, which extends ventrally to the level of the quadratojugal bar and is situated so far anteriorly as almost to abut the postorbital process.
Jugal (Ju): caudally, the jugal articulates with the rostral rim of the quadratojugal.
Ventrolaterally, the parietal articulates with the prooptic and laterally with the medial edge of the quadratojugal (Figures 1A and B).
When viewed laterally, the rostral edge of each squamosal articulates with the quadratojugal and with the caudomedial edge of the quadrate bone (Figures 1A and B).
The quadratojugal lacks a dorsal process and is not C-shaped (Fig.