What is "laaroussien"

The Laaroussien (; also spelled Larosien, Laârousienne, Aarousiyine, al-Arosien, etc.) is a Sahrawi tribe traditionally migrating within the region that is today the disputed territory of Western Sahara. Their migratory routes stretched from El Aaiún down towards Dakhla, parallel to the coast of the territory. Like all Sahrawis, they are Sunni Muslims of the Maliki madhhab.