TRAMPLED BY TURTLES Authenticity's a slippery concept. One person can hear it in these up-and-coming Duluth headliners, while another turns away from yet another generic Avetts/Mumford knockoff picking at the bleached bones of roots music with "authentic" instrumentation. To their credit, and despite the ridiculous band name, Turtles do kick up significant dust, in part by virtue of their chops but mostly because they pen a decent tune. With William Elliot Whitmore. $18-$33. Neighborhood Theatre.