It’s just as related as the 3 American black widows or the European one are to each other, they are all species in Latrodectus. And while most Aussies do call them redbacks calling them Australian black widow isn’t unheard off, especially by non-Aussies.
It’s the term “black widow” that’s ambigious here, it doesn’t refere to one specific species of spider.
Redbacks are a related bit different spider. But yes, Aussies have redbacks.
It’s just as related as the 3 American black widows or the European one are to each other, they are all species in Latrodectus. And while most Aussies do call them redbacks calling them Australian black widow isn’t unheard off, especially by non-Aussies.
It’s the term “black widow” that’s ambigious here, it doesn’t refere to one specific species of spider.