The keyboardist, a veteran of several bands, was in his 50s

Vince Welnick, the Grateful Dead’s last keyboard player, died Friday of undisclosed causes, according to the group’s longtime publicist. Various sources give his age as 51 or 55, the Associated Press reports.

Welnick, who also played in bands including the Tubes and Missing Man Formation, lived in the northern California town of Forestville. The Sonoma County coroner’s office said an autopsy would be performed next week.

“The big thing about Vince was that he had that fearlessness to be able to go and just jump into our madness and just operate on it like it was a normal, everyday procedure,” Grateful Dead drummer Mickey Hart recalled Saturday. “A lot of people can play, but with us they just don’t know how to navigate. Our music is different.”

The band, which was formed in 1965 and joined by Welnick in 1990, retired the name Grateful Dead and quit touring after singer and lead guitarist Jerry Garcia died of a heart attack in 1995. The death of the group’s unofficial leader was said to have hit Welnick particularly hard.

In the years following Garcia’s death, Welnick, who formed his own group, Missing Man Formation, occasionally went on tour and had been scheduled to perform later this month, according to his Web site.

He is survived by his wife, Lori.