Rugosa, an extinct order of coral, whose rugose shape earned it the name
Idiosoma nigrum, also called Black rugose trapdoor spider, occurs only in south-western Australia, in dry woodlands east of the Darling Scarp and north to Moore River.
An example can be seen in the mygalomorph spider Idiosoma nigrum (Black Rugose Trapdoor Spider), which protects itself in its burrow by positioning itself so as to block the burrow with its abdomen, which is unusually hard.
The corals which build reefs today, the Scleractinia, arose after the Permian–Triassic extinction event that wiped out the earlier rugose corals (as well as many other groups), and became increasingly important reef builders throughout the Mesozoic Era.