part of part of embryonic structure pharyngeal arch 1 1st arch maxillary component UBERON:0007238 relationship to palatoquadrate to be added 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] EHDAA2:0000038 EMAPA:16388 EHDAA:595