Pharyngeal arches are series of anterior tissue bands present under the early brain which form the head and neck structures. They are also called as visceral arches and are visible in the embryonic stage of vertebrates. They are derived from all three germ layers.
In human embryo these arches are first observed during fourth week of development. They appear as mesoderm extensions on both sides of developing pharynx.
In fish these arches are also known as branchial arches and they support the gills.