Niobeus
Could not find Niobea in Logeion dictionaries.
Niobea Proper-name adjective: neuter nominative plural, Proper-name adjective: neuter vocative plural, Proper-name adjective: feminine nominative singular, Proper-name adjective: feminine ablative singular, Proper-name adjective: feminine vocative singular, Proper-name adjective: neuter accusative plural of Niobeus
Nĭŏbēus, (16) a, um, de Niobé : Hor. O. 4, 6, 1 || -bĭdēs, æ, m. , fils de Niobé : Hyg. Fab. 11.