Australian Red-back Spider Latrodectus (Red-back Spiders) hasseltii Thorell, 1870

Latrodectus hasseltii is the only Australian species of Latrodectus. It has been introduced to New Zealand and the following diagnosis can be used to distinguish it from L. katipo in that country (after Vink et al. 2008): Latrodectus katipo differs from its sister-species, L. hasseltii, by the following characters: the abdomen of the female is covered in short fine setae (L. hasseltii has both long fine setae and stouter short setae); the female patella–tibial index (the total length of the patella and tibia of leg I divided by the carapace length from the clypeal apex to the posterior notch) is 1.58 (it is 1.86 in L. hasseltii); in the male pedipalp, the edge of the theridioid tegular apophysis (TTA) is curled ventrally so that the knob-like projections on the dorsal surface of the TTA are visible at the anterior and ectal edges of the TTA when viewed ventrally (the knob-like projections are not visible in the ventral view of L. hasseltii); a triangular-shaped sclerotised area at the base of the embolus (can be present or absent in L. hasseltii); in the female genitalia, the rounded anterior end of the spermatheca is approximately one-third of the total length of the spermatheca (approximately one-half the total length of the spermatheca in L. hasseltii); there is a posteriorly directed hump at the centre of the anterior edge of the depression of the external genitalia (the posteriorly directed hump can be present, reduced or absent in L. hasseltii).

• New South Wales
• Queensland
• South Australia
• Tasmania
• Victoria
• Western Australia