The confounding metallic attack of Bay Area squad Intronaut continues with PREHISTORICISMS, a brazen eight-track affair whose dense subject matter and dizzying musical output pushes the envelope past the point of no return. Despite losing guitarist Leon Del Muerte (the man mainly responsible for the unit's grind and death side), this troupe enlisted another guitarist (David Timmick), adding a bevy of stylistic tricks to their avant garde extreme metal approach. While guitars on cuts "Cavernous Den of Shame" still manage to bash your skull in, Del Muerte's absence is definitely apparent and truly marks a discernible shift for the group. The percussive work of Danny Walker proves once again to be a mighty force (be sure to check out the near two-minute drum solo on "Any Port") that will have all skin bashers running to theit kit to brush up on chops. But the true MVP of this endeavor is bassist Joe Lester, whose sinewy bass lines, sweeping fills, and massive four-stringed solo assaults practically lead each song from attack mode into strange and wondrous soundscapes that morph and twist the sonic batterings of metal into shards of progressive jazz fusion. Fear not though, Intronaut remains a hulking beast of a band that rivals Gojira and Meshuggah in terms of unabashed heaviness, only now their multi-faceted display is sharper and more adventurous, yielding an exhilarating listening experience through and through.