Rufus Jagneaux, ‘The Opelousas Sostan Collection’ (Jin Records)

Rufus Jagneaux etched its name in the annals of South Louisiana music with the 1971 hit “Opelousas Sostan,” written by bassist Benny Graeff. Though the joyful, easy-to-sing-along-with tune was its signature hit, Jagneaux was hardly a one-hit wonder. The group was one of the biggest of its day, gigging four to five nights a week and opening for such acts as B.B. King, ZZ Top and Dr. John. It left behind an intriguing body of original work (1971-1975) that is only now available on CD in the form of this bountiful 26-track, two-volume collection.

Like “Sostan,” Rufus incorporated elements of its Southwest Louisiana identity, as evidenced by the southern rock-toned “Sha T Babe,” the wacky “Port Barre” and the harmonica-powered “Quadroon.” Jagneaux even covered Cajun blockbusters such as DL Menard’s “The Back Door,” sung mostly in English and fueled by a psychotic-twangy guitar, and Jimmy C. Newman’s “Lache pas la patate.”

Moreover, this collection shows how Jagneaux evolved exponentially beyond its swampy country-rock baseline into a progressive jazz-rock-funk-soul fusion with arrangements including piano, congas and horns. “(Here to) Carry On” is a prime example of concurrently moving parts: Crosby, Stills & Nash-like vocals, a quick-darting clarinet, hard-rapping congas, Graeff’s fat, funky bass and Dana Breaux’s interleaving guitar lines.

The 6:38-long “Tempted” is even better. A simple rhythm precedes a hard-boppin’ sax and a quirky street-life narrative. Soon there’s a jukin’ jazz jam between sax, guitar, percussion and trumpet before returning to the storyline. It’s a far cry from “Opelousas Sostan” that ignited all of this in the first place.