C. australis

C. australis may refer to:
 * Ceuthmochares aereus, the Yellowbill, a bird species found in Africa
 * Chaetorellia australis, the yellow starthistle peacock fly, a fly species native to southern Europe and the Mediterranean
 * Charadrius australis, the Inland Dotterel or Australian Dotterel, a medium-sized plover species found in Australia
 * Cirrhigaleus australis, the Southern Mandarin dogfish, a shark species
 * Citrus australis, the round lime or Australian lime, a large shrub or small tree found in Australia
 * Cordyline australis, the cabbage tree, a monocotyledon plant species endemic to New Zealand
 * Ctenomys australis, the Southern tuco-tuco, a rodent species endemic to Argentina.
 * Cyathea australis, the rough tree fern, a tree fern species native to Australia
 * Cyclaspis australis, a crustacean species in the genus Cyclaspis