mastodonsaurian,a.|ˌmæstədɒnˈsɔːrɪən| [f.mod.L. Mastodonsaur-us (Jæger 1838, f.Gr. µαστός breast + ὀδοντ-, ὀδούς tooth + σαῦρος lizard) + -ian.] Of or belonging to the Mastodonsaurus, a genus of Labyrinthodonts. 1865Lyell Elem.Geol. (ed. 6) 508 Labyrinthodonts of the Mastodonsaurian type.