LOS ANGELES - Phil Lesh, an innovative bassist and founding member of The Grateful Dead, died on Friday, according to a statement on his Instagram account. He was 84 years old.
Over three decades, the classically trained Lesh and Grateful Dead icon Jerry Garcia shared a close musical partnership that resulted in the eclectic California rock band's psychedelic sound and famed onstage improv.
Lesh "passed peacefully" and was "surrounded by his family and full of love," the statement said.
"Phil brought immense joy to everyone around him and leaves behind a legacy of music and love."
Lesh was an early pioneer in the 1960s burgeoning electric bass sound, adopting a more melodic, improvisational approach to the instrument that was traditionally more of a timekeeper, with his chords dominating rather than in the background.
He was far from the band's most prolific writer but he co-wrote some of the Dead's most notable, jam-worthy tracks -- "Dark Star" and "St. Stephen" among them -- and also sang harmonies for the band, and less often led vocals.
As the Grateful Dead, the band members became key figures in the counterculture starting in the 1960s and revolutionised fan engagement, with "Deadheads" traveling from show to show.
Many followers recorded and swapped bootleg tapes of the concerts and enjoyed a communal drug-addled camp environment.
The rockers disbanded in 1995, a few months after Garcia's death.
"Jerry was the hub," Lesh later told Rolling Stone. "We were the spokes. And the music was the tread on the wheel."
Lesh continued to perform in the tradition of the Dead in various iterations for decades. He retired from regular touring in 2014.
In 1998 Lesh underwent a liver transplant after a hepatitis C infection -- after which he used his concerts as a platform to encourage fans to become organ donors.
In 2015 he said he had cancerous bladder tumors that followed a 2006 prostate cancer battle.