The position of jaw structures representing junctions between Meckel's and palatoquadrate
cartilages (point A and B) and representing junctions between the hyosymplectic and ceratohyal cartilages (point C and D) was measured relative to a reference point as shown.
The first one is the mandibular arch, including the palatoquadrate
(upper mandible) and Meckel's cartilage (lower mandible).
Both of these muscles originate from the ventral surface of the palatoquadrate and insert on the retroarticular process of Meckel's cartilage The third muscle, located ventrally to the two levator mandibulae muscles and posterior to the angularis group, is the orbitohyoideus.
Both muscles originate from the ascending process of the palatoquadrate, ventral to the posterior margin of the eye, and insert on Meckel's cartilage of the lower jaw.
The symphyses that loosely connect the two sides of the mandible (lower jaw) and of the palatoquadrate
(upper jaw) are fused in the rhinopterid and closely related myliobatid rays (Summers 2000).
Lateral ethmoid with cartilaginous process contacting palatoquadrate cartilage, ventral to condyle for lacrimal.
Suspensorium: Comprising palatoquadrate arch, ectopterygoid, mesopterygoid, ectopterygoid, symplectic, hyomandibula and preopercle (Fig 9).
(3, 4) The upper sections of the mandibular arch form the upper jaw (palatoquadrate
), and the lower sections form Meckel's cartilage, which gives rise to the lower jaw.
We first attempted to use morphometrics, dentition, and vertebral count and then, for unambiguous identification, we used skeletal anatomy--namely, the chondro-neurocranium, palatoquadrate
, and pectoral girdle.
The anterior part (QMA) originates in the palatoquadrate
cartilage, fibers run caudally, and the posterior part (QMP) inserts in mandibular cartilage..
The basihyoidean, together with the palatoquadrate
and mandibular cartilages, constitutes the mandibular arch.
This muscle possesses a portion that could be found in the orbita, dorsally to the palatoquadrate