The genus Latrodectus was erected by Charles Athanase Walckenaer in 1805, for the species Latrodectus tredecimguttatus and Latrodectus mactans.
Arachnologist Herbert Walter Levi revised the genus in 1959, studying the female sexual organs and noting their similarity across described species.
He concluded the colour variations were variable across the world and were not sufficient to warrant species status, and reclassified the redback and several other species as subspecies of the black widow spider.

Levi also noted that study of the genus had been contentious; in 1902, both F. O. Pickard-Cambridge and Friedrich Dahl had revised the genus, with each criticising the other.
Cambridge questioned Dahl's separating species on what he considered minor anatomical details, and the latter dismissed the former as an "ignoramus".
The genus Latrodectus was erected by Charles Athanase Walckenaer in 1805, for the species Latrodectus tredecimguttatus and Latrodectus mactans. Arachnologist Herbert Walter Levi revised the genus in 1959, studying the female sexual organs and noting their similarity across described species. He concluded the colour variations were variable across the world and were not sufficient to warrant species status, and reclassified the redback and several other species as subspecies of the black widow spider.
Levi also noted that study of the genus had been contentious; in 1902, both F. O. Pickard-Cambridge and Friedrich Dahl had revised the genus, with each criticising the other. Cambridge questioned Dahl's separating species on what he considered minor anatomical details, and the latter dismissed the former as an "ignoramus".
Latrodectus