eurystomatous,a.|jʊərɪˈstɒmətəs| [f.Gr. εὐρύ-ς broad + στόµα, στόµατ-ος mouth + -ous.] Wide-mouthed. Chiefly of serpents: Having a distensible mouth. 1878Bell Gegenbauer's Comp.Anat. 463 The two halves of the jaw are movably connected together in the eurystomatous Ophidii.