Welnick died Friday, said Dennis McNally, who declined to release the cause. The Sonoma County coroner’s office said Saturday that an autopsy would be performed next week. Welnick lived in the northern California town of Forestville, but McNally said he did not know if he died at home or in a hospital.

“His service to and love for the Grateful Dead were heartfelt and essential. He had a loving soul and a joy in music that we were lucky to share,” the group said in a statement on its Web site. “Our Grateful Dead prayer for the repose of his spirit: May the four winds blow him safely home.”

With long, frizzy hair and tie-dyed clothes, Welnick clearly looked the part of a member of a band that was born in 1965 in San Francisco, then the cradle of the country’s emerging psychedelic counterculture. But the fact was he was largely unfamiliar with the band’s music when he joined the group in 1990, and he would recall afterward that he was so nervous he could barely play at his first show with them in Cleveland. He was quickly put at ease when the audience gave him a warm welcome.

“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.”

Hart recalled Welnick as not only a “nimble” keyboard player but also a fine background singer whose vocals added much to the group’s songs.

“He had this real high harmony. He could go where others couldn’t,” Hart said.

Welnick, who grew up in Phoenix, moved to San Francisco in the early 1970s with the Beans, which soon renamed itself the Tubes. After the group temporarily disbanded in the mid-1980s, he worked with Todd Rundgren before joining the Grateful Dead.

He was the last in a long line of Grateful Dead keyboardists, several of whom died prematurely, leading some of the group’s fans to conclude that the position came with a curse.

He had replaced Brent Mydland, who died of a drug overdose in 1990. Mydland had succeeded Keith Godchaux, who died in a car crash shortly after leaving the band. Godchaux had replaced the band’s original keyboard player, Ron “Pigpen” McKernan, a heavy drinker who died in 1973 at age 27.

McNally recalled that the legend of the curse took a lighthearted turn at Welnick’s first performance with the Grateful Dead.

“Just before he was to go on for the first time, one of the sound guys went over and sat down at Vince’s seat in front of the piano and it collapsed under him,” he said.

The fact was, though, that two other Grateful Dead keyboardists, Bruce Hornsby and Tom Constanten, survived the supposed curse just fine. Constanten worked with McKernan in the late 1960s, and Hornsby and Welnick played alongside one another for 18 months in the early 1990s.

The band retired the name Grateful Dead and quit touring after lead guitarist Jerry Garcia died of a heart attack in 1995. The death of the group’s unofficial leader hit Welnick particularly hard, McNally recalled Saturday.

“When he joined the Grateful Dead he really embraced the opportunity, both musically and emotionally,” McNally recalled. “And to lose it within five years hurt him maybe worse than anybody else in the band.”

In the years following Garcia’s death the group’s other longtime members have occasionally toured as The Other Ones or The Dead.

Welnick, who formed his own group, Missing Man Formation, occasionally went on the road himself and had been scheduled to perform later this month, according to his Web site.

Survivors include his wife, Lori.