J.R. Monterose is a saxophonist rarely heard even by jazz fans, and his most well-known recording, Charles Mingus’ Pithecanthropus Erectus, is one that Monterose himself later all but disowned. He recorded only sporadically as a leader and withdrew from the jazz world several times, woodshedding or playing in towns distant from the music’s metropolitan centers. His sound, although influenced by other tenor horns such as…