Beausoleil may be as synonymous with Cajun culture as Tasso ham, gumbo filé, and mudbugs, but the veteran shape-shifting Zydeco act is as adept at creating fusion food as it is traditional fare. Bandleader Michael Doucet’s evenhanded fiddling and expressive, amiable voice lead the charge on Alligator Purse, the band’s first for the Yep Roc label. Beausoleil flex their Cajun backbone on opener “Reel Cajun/452 North St. Joseph St.,” one of a handful of straight-up bayou barnburners (“Carrière Zydeco,” “Bosco Stomp”) that are as timeless as they are electrifying, but it’s the band’s penchant for seamless genre-hopping that solidifies its well-deserved reputation as an American institution. Doucet and his small but formidable army’s tasteful renderings of the blues (“Rouler et Tourner”), jazz (“Marie”), and old-timey country (“Little Darlin’”) — the latter featuring some high and lonesome crooning from Natalie Merchant — always keep true to regional ingredients like accordion, Dixieland horns, and a steady Cajun backbeat, resulting in the kind of all-day street party that welcomes both purists and tourists with open arms, cold beer, and steaming plates of Louisiana cooking. – James Christopher Monger