Exclusive Details

NBA legend Darryl Dawkins -- nicknamed "Chocolate Thunder" for his monster dunks -- has died at the age of 58 ... TMZ Sports has confirmed.

Officials tell us ... a family member called 911 to respond to a medical emergency this morning -- and Dawkins was transported to a nearby hospital.

Unfortunately, Dawkins was not able to recover and was pronounced dead at 11:19 AM. The nature of the medical emergency is unclear at this point.

We're told there was nothing suspicious about his death and no indication of foul play.

An autopsy is scheduled for tomorrow.

Dawkins was the first basketball player to be drafted to the NBA straight outta high school when he was selected by the Philadelphia 76ers in 1975.

Dawkins played in the NBA until 1989 ... and also spent time playing with the Harlem Globetrotters.

The guy was a pioneer of the monster dunk -- and threw down with such force that he shattered TWO backboards in 1979.

Dawkins was always cool with us ... and just last year explained how Stevie Wonder gave him his famous nickname.

R.I.P.

1:45 PM PT -- Darryl's family says he died from a heart attack today. In a statement they said, "More than anything Darryl accomplished in his basketball career ... he was most proud of his role and responsibility as a husband and father."

1:20 PM PT -- A rep for the Sixers tells us ... "We’ve lost a dear friend and an iconic figure, both on and off the court. We remember fondly not only his thunderous dunks, but more importantly his powerful presence and personality. Simply put, Darryl Dawkins was beloved—by his family, friends, former teammates and his fans all over the globe."

The rep added, "Chocolate Thunder will always have a special place in our hearts. His family is in our thoughts and prayers.”