A songbird is a bird belonging to the clade Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as a scientific or vernacular name is Oscines, from Latin oscen, "a songbird". This group contains some 4,000 species found all over the world, in which the vocal organ typically is developed in such a way as to produce a diverse and elaborate bird song. There is evidence to suggest that songbirds evolved 50 million years ago in the part of Gondwana that later became Australia, New Zealand, New Guinea and Antarctica, before spreading around the world.