| A. Santos-Cubedo et al. 2021 | Styracosternan hadrosauroid distinguished by two autapomorphies: the absence of a bulge along the ventral margin directly ventral to the base of the coronoid process, convergent with the two more derived hadrosauroids Altirhinus kurzanovi and Sirindhorna khoratensis, and the presence of a deep oval cavity on the medial surface of the mandibular adductor fossa below the eleventh-twelfth tooth position. Internally, the cavity connects with the last nutrient foramina (the most caudal).
It is also diagnosed by the following unique combination of features: (1) a straight morphology of the ventral margin of the rostral ramus (convergent with Iguanodon, Ouranosaurus, Barilium, Lanzhousaurus, Jinzhousaurus, Bolong, and Dakotadon); (2) rostral tip not raised respect to the ventral margin (unlike in Ouranosaurus, and Bolong); (3) dorsal and ventral margins parallels (unlike in I. galvensis, and O. nigeriensis with divergent dorsal and ventral margins); (4) presence of a diastema (unlike in Lanzhousaurus, and Dakotadon); (5) absence of a bulge along ventral margin directly ventral to the base of the coronoid process (unlike in Jinzhousaurus, and Ouranosaurus). | |