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

The 6 species that are indistinguishable from one another by photographs are:

Latrodectus mirabilis: In most of its geographical distribution, it does not overlap with any species, and in some areas, it overlaps with L. corallinus and L. quartus. It inhabits Patagonia, except for 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 geographical distribution does not overlap with any other species. It inhabits central La Rioja and parts of Catamarca and San Juan.
Latrodectus antheratus: Its geographical distribution overlaps with that of 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 geographical distribution does not overlap with any other species. It inhabits southern Neuquén.
Latrodectus quartus: Its geographical distribution overlaps with that of L. mirabilis. It inhabits central San Luis, and parts of Mendoza, Córdoba, and La Pampa.
Latrodectus corallinus: Its geographical distribution overlaps with that of 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 using 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 geographical distributions of species.