Anmar is an Arabic tribe consisting mainly of the Qahtanite, Adnanite and Ishmaelite Arabs. Anmar in Arabian means : "clean water".
While Mudar was supposed to have a son, Anmar's tribes had perished. The Prophet says Anmar was one of the tribes of Yemen, a son of Saba the Qahtanite.
References
Anmar Wikipedia(Text) CC BY-SA