Figure 1. Proposed terminology and annotation of the nonavian theropod maxilla.

Right maxilla of Allosaurus fragilis (USNM 8335) in A, lateral; B, anterior; C, medial and D, posterior views, with details of E, promaxillary recess and maxillary antrum in medial view; and F, ascending ramus and dorsal margin of vestibular bulla in dorsal view. Abbreviations: ammf, anteromedial maxillary fenestra; amp, anteromedial process; anr, anterior ramus; aor, antorbital ridge; asr, ascending ramus; idw, interdental wall; ifs, interfenestral strut; juc, jugal contact; lac, lacrimal contact; laof, lateral antorbital fossa; law, lateral wall; maf, maxillary alveolar foramina; man, maxillary antrum; maof, medial antorbital fossa; mbo, maxillary body; mcf, maxillary circumfenestra foramina; mes, medial shelf; mew, medial wall; mfe, maxillary fenestra; mfo, maxillary fossa; mmf, medial maxillary foramina; mx1, first maxillary tooth; nac, nasal contact; nuf, nutrient foramina; nug, nutrient groove; pac, palatine contact; pmc, premaxillary contact; pmmf, posteromedial maxillary fenestra; pmr, promaxillary recess; pne, pneumatic excavation; poas, postantral strut; pras, preantral strut; snf, subnarial foramen; suas, suprantral strut; veb, vestibular bulla. Scale bars = 5 cm.