Ranks are equal to the guild ranks.

Member= Civilian
Crew= Warrior
Vice President= Elite Warrior (aka. general/ council member)
President= Tribe Leader

Also, Tribe names are related to Rank as-well, they will change when your rank changes as well so if you are a Civilian, you might have a name depending on your duty in the Tribe such as Sistercaller if the task you choose is to invite others to join the Tribe, or if your character is a blacksmith she might have a last name of Metalshaper, ect. ect.