in taxon develops from develops from composed primarily of Theria <mammals> Homo sapiens auditory ossicle bone incus bone http://upload.wikimedia.org/wikipedia/commons/d/df/Gray917.png quadrate - incus MA:0001215 FMA:52752 The incus or anvil is the anvil-shaped small bone or ossicle in the middle ear. It connects the malleus to the stapes. It was first described by Alessandro Achillin of Bologna. The incus transmits sound vibrations from the malleus to the stapes. The incus only exists in mammals, and is derived from a reptilian upper jaw bone, the quadrate bone. Embryologically it is derived from the first pharyngeal arch along with the rest of the bones of mastication, such as the maxilla and mandible. [WP,unvetted]. incus bone 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] SCTID:272649008 Wikipedia:Incus UBERON:0001688 EMAPA:18583 NCIT:C32770 incus UMLS:C0021181 GAID:866 MESH:D007188 bone tissue endochondral bone incus cartilage element incus endochondral element