part of part of embryo pharyngeal arch 1 developing anatomical structure 1st arch mandibular component EHDAA2:0000031 EHDAA:583 EMAPA:16382 Subsequent vertebrate evolution has also involved major alterations to the pharynx; perhaps the most notable occurred with the evolution of the gnathostomes. This involved substantial modifications to the most anterior pharyngeal segments, with the jaw forming from the first, anterior, pharyngeal segment, while the second formed its supporting apparatus, the hyoid.[well established][VHOG] UBERON:0007237 VHOG:0000510 relationship to Meckel's cartilage to be added uberon ventral mandibular arch ventral pharyngeal arch 1 ventral visceral arch 1