It’s official. Paz Lenchantin, who’s been playing bass for The Pixies since 2014, has been made a permanent member of the Boston-bred band. Guitarist Joey Santiagoalerted fans on Facebook: “Paz Lenchantin is officially a Pixie!!!’’ Lenchantin, who previously played with Entrance, A Perfect Circle, and Zwan, joined Frank Black, Santiago, and drummer David Lovering after original Pixies bassist Kim Deal decided not to continue (and a subsequent interlude with bassist Kim Shattuck didn’t work out.) In September, The Pixies will release a new CD, “Head Carrier,’’ and the first single, “Um Chagga Lagga,’’ is online now. “I spent three years learning to understand what being a Pixie meant, and now, my heart, spirit, and love for their music is embedded in me and I feel like I have become a Pixie,’’ Lenchantin told RollingStone.com. “We had been more about the history of the Pixies, but now, we are about going forward.’’