(...) mouth development is very similar in protostomes and 'basal' deuterostomes, whereas the chordate mouth seems to develop at a new position. Recent data for echinoderms and hemichordates further suggest that this change in mouth position may result from change in the influence of a conserved ectodermal patterning system on mouth development. It has been suggested that the mouths of vertebrates and urochordates may constitute a 'new' mouth.[well established][VHOG]

The orifice that connects the mouth to the exterior of the body.

oral orifice

oral fissure

uberon

mouth

oral part of face

UBERON:0000166