Abstract: The scorpion Mesobuthus vesiculatus (Pocock, 1899) was briefl y described from northwestern Iran based
on only one male with a picture indicating the dorsal habitus of the holotype; the author pointed out that it has a large
and globular telson with a short aculeus. Th is species, with very distinct morphological features, is now redescribed
based on new specimens (3 ♂♂, 3 ♀♀) collected from West Azerbaijan and East Azerbaijan (Iran). Detailed fi gures
and measurements are presented and the trichobotrial pattern and paraxial organ are illustrated for the fi rst time. Th e
morphological diff erences of M. vesiculatus from similar species M. caucasicus, M. eupeus, and Sassanidotus gracilis are
discussed.