In Argentina, the genus Latrodectus is represented by 7 species, of which only L. geometricus can be distinguished by photographs. The remaining 6 species are indistinguishable from each other through photographs and have a wide variety of dorsal markings that do not help differentiate them.

The 6 species that are indistinguishable from each other by photographs are:

Latrodectus mirabilis: In most of its geographic distribution, it does not overlap with any species, and in some areas, it overlaps with L. corallinus and L. quartus. It inhabits Patagonia, excluding the Andean-Patagonian forest and Tierra del Fuego. It also inhabits La Pampa, Buenos Aires, San Luis, and parts of Mendoza, San Juan, La Rioja, Córdoba, Santa Fe, and Entre Ríos.
Latrodectus diaguita: Its geographic distribution does not overlap with any other species. It inhabits the center of La Rioja, and parts of Catamarca and San Juan.
Latrodectus antheratus: Its geographic distribution overlaps with L. corallinus and L. mirabilis. It inhabits Formosa, Chaco, Santiago del Estero, and parts of Salta, Jujuy, Tucumán, Catamarca, Córdoba, and Santa Fe.
Latrodectus variegatus: Its geographic distribution does not overlap with any other species. It inhabits the south of Neuquén.
Latrodectus quartus: Its geographic distribution overlaps with L. mirabilis. It inhabits the center of San Luis, and parts of Mendoza, Córdoba, and La Pampa.
Latrodectus corallinus: Its geographic distribution overlaps with L. antheratus. It inhabits Formosa, Chaco, Santiago del Estero, and parts of Salta, Jujuy, Tucumán, Catamarca, La Rioja, Córdoba, and Santa Fe.

Comment by: Luciano Peralta and Jorge La Grotteria.

For the purposes of the site, records from unexamined specimens with keys should be published according to the following criteria:

Latrodectus geometricus.
Latrodectus mirabilis: When the locality does not include L. corallinus or L. quartus.
Latrodectus diaguita.
Latrodectus variegatus.
Latrodectus sp.: When the locality has overlapping geographic distributions of species.