Jether: Jether, יתר [Strong's H3500], is essentially the same with יתרא [Strong's H3501], Ithra, the latter only having the addition of an א aleph; and it is probable, that he was an Ishmaelite by birth but an Israelite by religion. 2Sa 17:25, Ithra an Israelite
Ishmeelite: [Strong's H3459] a descendant of Ishmael