Rusubisir was an ancient Roman town of the Roman province of Mauretania Caesariensis.David M. Cheney, Rusubisir at Catholic-hierarchy.org. An exact location of the town is not currently known but it presumed to be in the territory around Tiza, Algeria. Titular Episcopal See of Rusibisir, at GCatholic.org.
Rusubisir was also the seat of an ancient bishopric which survives today as a titular see of the Roman Catholic Church. The current bishop is Mons. Juan Alberto Ayala. Titular Episcopal See of Rusibisir, at GCatholic.org.
References
Obispo Titular Actual: Juan Alberto Ayala Ramírez (Venezuela) https://www.gcatholic.org/dioceses/former/t1484.htm