Idiosoma nigrum, female (Minnivale, WA) - Shield-backed Trapdoor Spider
These spiders are restricted to the northern Wheatbelt region in Western Australia. They are currently (2017) the only species listed as Threatened under Federal legislation (EPBC Act). They are believed to be threatened by habitat destruction and fragmentation. A number of spider species have a rugose abdomen like this and are subject to a taxonomic study by Michael Rix (Queensland Museum) and collaborators.