AUSTIN, TEXAS — Watching the rollicking celebration of musical inclusion that is Los Super Seven blowing the roof off the La Zona Rosa Club on Thursday night (March 15) near the end of the first full day of the 15th annual South by Southwest Music Conference and Festival, one couldn't help but reflect on the fact that when the all-star "pickup" group's ringleaders, Los Lobos guitarists/singers Cesar Rosas and David Hidalgo, first hit the national music scene from East L.A. more than two decades ago, they did so as adjuncts to that city's punk/new wave scene. Back then, so-called roots music — especially if it had a strong beat and was played by young musicians — found little room at the mainstream inn, and bands such as Los Lobos and L.A. brethren the Blasters found refuge under the "us-not-them, so-why-not?" umbrella of punk rock.

Twenty-odd years later, and the politics of inclusion still guides the musical aesthetic of these surviving wolves. Between the release of the eponymous Tex-Mexcentric Los Super Seven album in 1998 and the group's brand new follow-up, Canto, the band has widened its geographical scope via contributions from artists of Cuban, Central and South American descent. While the touring band's roster doesn't include Brazil's Caetano Veloso or Peru's Susana Baca, who appear on Canto, one needn't look further than pianist Alberto Salas and vocalist Raul Malo to see how far-reaching Los Super Seven's mission has become.

Whether soaring Roy Orbison-like over the dreamy old Cuban ballad "Siboney," or lending muscular high harmonies behind the leads of fellow country star Rick Trevino (the pulsating "El Que Siembre Su Maiz"), Mavericks lead singer Malo adds a new dimension to Los Super Seven's vocal capabilities. And in the Cuban/Costa Rican Salas, the group has found a bandleader/arranger whose playing is a dazzling amalgam of jazz and salsa, thus adding new textural layers to even the more folk-flavored of Los Super Seven's material.

With Ruben Ramos, their irrepressible elder statesman functioning as combination de facto MC and stage commandant, the musical spotlight shifted constantly from player to player and from style to style. It drifted from Ramos' troop-rallying opening song shout-out, "Company Gato," Hidalgo's stutter-stepping "Calle Dieceseis" and Rosas' bull-horned blues, "Campesino," to a flurry of drum and percussion solos from the band's muscular rhythm section, with even a half-rap from one of the band's stream of guest performers.

By the finale of Los Super Seven's 50-minute set a full baker's dozen of players were onstage, with additional guitar, trumpet and trombones tossed into the delirious mix. Even band producer Steve Berlin, a former Blaster and present Lobo, was honking away on baritone sax. It's during moments like these — when songs rich with history are stretched across interconnected cultures and delivered almost entirely in a language most of a jam-packed audience doesn't speak but fully embraces nonetheless — that one's faith in the power of music to bring people together gets the kind of recharging that festivals like South By Southwest are all about.