page_title: Latrodectus
section_title: Taxonomy
hierarchical_section_title: Latrodectus / Taxonomy
context_page_description: Latrodectus is a broadly distributed genus of spiders with several species that together are referred to as true widows. This group is composed of those often loosely called black widow spider, brown widow spiders, and similar spiders. However, such general "common names" are of limited use as the diversity of species is much greater. A member of the family Theridiidae, this genus contains 32 species, which include several North American "black widows". In addition to these in North America are also the Red Widow Latrodectus bishopi and the Brown Widow Latrodectus geometricus, which, in addition to North America, has a much wider geographic distribution. Elsewhere, others include the European black widow, the Australian redback black widow, several different species in Southern Africa that can be called Button spiders, and the South American black widow spiders. Species vary widely in size. In most cases, the females are dark-coloured, but some may have lighter bodies or even reddish. Many can have red, white or brown markings on the upper-side of the abdomen. Some can be readily identifiable by reddish markings on the central underside abdomen, which are often hourglass-shaped.
context_section_description: 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".
caption: L. hesperus with egg sac
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