Poised to gracefully undulate into its fifth decade, the Revolutionary Snake Ensemble’s fifth album, Serpentine, is a joyously uproarious live session recorded in 2024 at the Regattabar as part of the group’s 35th anniversary run.

Led by inveterately inventive alto saxophonist, flutist, and composer Ken Field, the RSE is a musical insurrection with enviable longevity. As NYC Jazz Record noted, the group has earned a devoted following with “its unique and somewhat twisted twist on the New Orleans brass band tradition…hard-partying avant-funk, with boisterous soloing.”

“The concept of not having a chording instrument in the band allows for tremendous freedom on the part of the horn players. The arrangements are usually spontaneous, decided by me on stage based on the group vibe and on my vibe at the moment!”

Spirits were obviously high at the Regattabar, one of the Boston area’s leading jazz venues. The RSE sounds loose and limber, delivering one thrilling piece after another, enviably undaunted by the prospect of making a new album with Field changing up arrangements on the spot. “I told the guys, ‘Don’t worry about the fact that we’re recording,’” Field says. “‘Don’t hold back. Take chances.’ Jazz is an experimental form. If you do the same thing every night you’re not doing jazz right, in my opinion.”

Decked out in feathered and metallic finery that evokes Sun Ra’s Arkestra as much as the Mardi Gras Indians, the RSE has always honored the essential role of New Orleans brass bands in providing succor and uplift to mourners accompanying loved ones for burial (while also fulfilling the celebratory imperative for the promenade back from the cemetery).