What is "riototar"

Riototar (also Riotutar, Reotutar, and Retutar) is an extremely rare Filipino surname used mainly in the island of Luzon, Philippines since the eighteenth (18th) century. Of the handful of the present-day Riototars (Reotutars), most reside in the city of Vigan and in the towns of Santa Catalina and San Vicente in the province of Ilocos Sur.