Squamosal bone
The squamosal is a skull bone found in most reptiles, amphibians, and birds.[1] In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull.[3] The squamosal bone lies ventral to the temporal series and otic notch, and is bordered anteriorly by the postorbital.[4] In reptiles, the quadrate and articular bones of the skull articulate to form the jaw joint.In mammals, the quadrate bone evolves to form the incus, one of the ossicles of the mammalian ear.
synapsidEvolution of mammalian auditory ossiclesreptilesamphibiansquadratojugalventralpostorbitalquadratepterygoidarticularsynapsidsquadrate bonestherapsidsdentarysquamoustemporal boneperiotic boneauditory bullasquama temporalisossicles of the mammalian earmalleusRoemer, A. S.tetrapodskeletonCraniumSkull roofFrontalIntertemporalZygomaticLacrimalMaxillaParietalPostfrontalPostparietalPrefrontalPremaxillaRostralSquamosalSupratemporalTabularInterparietalBasioccipitalEthmoidExoccipitalOrbitosphenoidParasphenoidSupraoccipitalOccipitalParabasisphenoidPetrosalTemporalEpipterygoidAlisphenoidPalatineColumellaStapesEntotympanicSclerotic ringWormian bonesMandibleAngularEctotympanicPredentarySplenialSurangularStylohyoidThyrohyoidVertebraeProatlasCervical vertebraeDorsal vertebraeSacrumCaudal vertebraeCoccyxPygostyleHaemal archesCervical ribCaudal ribAppendicularPectoral girdleClavicleFurculaCleithrumCoracoidInterclavicleScapulaSternumForelimbHumerusRadius (bone)CarpusScaphoidUlnareTriquetralIntermediumLunatePisiformPteroidTrapeziumTrapezoidCapitateHamateMetacarpalPhalangesUngualPelvic girdleIschiumEpipubic boneHindlimbFibulaPatellaTarsusTibialeFibulareCalcaneumMedial cuneiformIntermediate cuneiformLateral cuneiformAstragalusNavicularCuboidMetatarsalBaculumBaubellumGastraliaOssified tendon