10:00 AM PT -- Vinnie's family told TMZ ... he died in his sleep at his home in Las Vegas. His body's been turned over to the medical examiner to determine a cause of death, and after that he'll be flown back to his home state of Texas to be buried between his mom and brother.Vinnie Paul, a drummer and one of the original members of Pantera was 54.

Paul was a founding member of the metal band, which formed in the '80s. His brother, "Dimebag" Darrell Abbot, was also a founding member. The band was huge in its day ... nominated for Grammys in 1995 and 2001. Their album, "Far Beyond Driven," hit #1 in 1994.

The group fell apart in 2003 ... by all accounts band members were feuding.  

Vinnie's brother, Dimebag, was shot and killed a year later during a concert, after a man ran up on stage and began shooting ... killing a total of 4 people.

The cause of death is still unknown.