Brazil (middle Amazon region), Rondonia.
Holotype: ZSBS 209/0, according to Roze, 1996 [215].
Type-locality: Rio Solimes, Brazil.
Four subspecies, namely M. s. spixii, Wagler, 1824; M. s. martiusi Schmidt, 1953; M. s. obscurus (Jan, 1872); and M. s. princeps (Boulenger, 1905) were recognized by Roze, 1983 [dated 1982], Mem. Inst. Butantan 46:305-338[334-335].
