Hyoid Bone - in Other Animals

In Other Animals

The hyoid bone is derived from the lower half of the second gill arch in fish, which separates the first gill slit from the spiracle, and is often referred to as the hyoid arch. In many animals, it also incorporates elements of other gill arches, and has a correspondingly greater number of cornua. Amphibians and reptiles may have many cornua, while mammals (including humans) have two pairs, and birds only one. In birds, and some reptiles, the body of the hyoid is greatly extended forward, creating a solid bony support for the tongue. The howler monkey Alouatta has a pneumatized hyoid bone, one of the few cases of postcranial pneumatization of bones outside Saurischia.