I found a the description of the succession of main mafia bosses in the province of Agrigento in Sicily (representatives of the province in the regional commission). I also inserted the dates of their staying in power, however some are missing as I didn’t manage to find them. Maybe somebody can fill up the missing parts.
It's from the book "Cosa muta" (Silent thing) by Alfonso Bugea.

????-????

Giuseppe Pitruzzella (forced to retire)

????-1981

Giuseppe Settecasi (murdered)
with
Gioacchino Pitruzzella (underboss)
Gerlando Caruana –> Paolo Campo –> Carmelo Colletti (consigliere)

1981-1983

Carmelo Colletti (murdered)
with
Gioacchino Pitruzzella (underboss; sentenced to 4 years; don’t know what happened later)
Antonio Ferro (underboss; died in freedom shortly after being released while indicted for murder)

1983-1991

Giuseppe Di Caro (murdered)

1991-1992

Ruling panel made composed of:

Salvatore Fragapane
Simone Capizzi (serving a life sentence)
Salvatore Di Ganci (recently released after serving 14 years)
Gioacchino Capodici (murdered)
Salvatore Gioia (murdered)

1992

Antonio Di Caro

1992-1995

Salvatore Fragapane (serving a life sentence)
with
Antonio Di Caro (underboss; murdered)
Cesare Lombardozzi (consigliere)

1995-????

Arturo Messina (died in prison while serving a life sentence)
Cesare Lombardozzi (in prison serving 13 years and 6 months)

????-1997

Leonardo Fragapane (died a natural death; don’t know if as a free man or in prison)

1997-????

Giuseppe Fanara (serving a life sentence)

2002-2010

Giuseppe Falsone (serving a life sentence)

2010-????

Gerlandino Messina (serving a life sentence)