Tartarus mullamullangensis, informally known as the Mullamullang cave spider, is a palm-sized, long-legged cave spider from Western Australia. Completely adapted to cave living, it is blind and totally lacks pigmentation, giving it a creamy white appearance. The cylindrical lampshade-shaped web is spun out between rocks. The species is closely related to spiders found in forests of Southern Australia. This makes it likely that T. mullamullangensis is a relict species from the time when the now arid region was much more humid.