Timna

Timna son to Eliphaz and grandson to Esau

This may be a misprint in 1Ch 1:36 because Timna was a concubine to Eliphaz, is this two or is this some mistake Gen 36:40 lists a Duke Timnah. But information says that the Duke was Female so was there a son Timna to Eliphaz or just the concubine?

1Ch 1:36  The sons of Eliphaz; Teman, and Omar, Zephi, and Gatam, Kenaz, and Timna, and Amalek. 

Gen 36:40  And these are the names of the dukes that came of Esau, according to their families, after their places, by their names; duke Timnah, duke Alvah, duke Jetheth,