(G.B. Sowerby 1825) - Common name Fighting Conch - Size range 40mm-95mm - Range: Sea of Cortez to N. Peru
 
Collected live by local panga boat hooka divers near Puerto Penasco, Mexico. 7-10 meters depth. Tides range 7 meters / 24 feet near Puerto Pensasco, so the divers usually go out during low tides to collect murex and other species for meat.
 
I did minimal cleaning to this shell, I just removed the snail and gave it a quick wash.  The thin periostracum is intact and operculum included.  I am grading this shell at F++.