The quadrate commonly has a triangular shape, with its lower vertex, or condyle, for articulation with the lower jaw, and an elongate postero-ventral or postero-dorsal elongate process. The presence of an elongate postero-ventral or postero-dorsal process is a synapomorphy of teleosts (Arratia and Schultze, 1990; Arratia, 1999).[TAO]

relationship loss: overlaps quadrate-metapterygoid joint (TAO:0001803)[TAO], relationship loss: overlaps quadrate-hyomandibula joint (TAO:0001801)[TAO]

Endochondral bone that commonly articulates with the ectopterygoid anteriorly, the metapterygoid dorsally, and the symplectic postero-medially. The quadrate is formed from the posterior part of the palatoquadrate cartilage, or pars quadrata. The quadrate is a paired bone.[TAO]

Endochondral bone that commonly articulates with the ectopterygoid anteriorly, the metapterygoid dorsally, and the symplectic postero-medially. The quadrate is formed from the posterior part of the palatoquadrate cartilage, or pars quadrata. The quadrate is a paired bone.

quadrate - incus

uberon

quadrates

According to this theory (Reichert-Gaupp theory), the mammalian stapes is derived from the reptilian columella, the incus from the quadrate and the malleus from the articular (...).[well established][VHOG]

UBERON:0006597

http://purl.obolibrary.org/obo/NCBITaxon_40674

In snakes, the quadrate bone has become elongated and very mobile, and contributes greatly to their ability to swallow very large prey items. In mammals the articular and quadrate bones have migrated to the middle ear and are known as the malleus and incus.