branchial arch development trait Any measurable or observable characteristic related to the morphology or physiology during formation and differentiation of the transient structures of the embryo that develop into regions of the head and neck in higher vertebrates; in fish and amphibians, they support the gills. Trait.ontology VT:0002884 gill arch development trait pharyngeal arch development trait visceral arch development trait craniofacial development trait embryonic development trait