Fauna of Australia predators which include abalone and rock lobster. Introduced invertebrate pests include the Asian mussel, New Zealand green-lipped mussel, black-striped mussel and the Northern Pacific seastar, all of which displace native shellfish. There are many unique marine crustaceans in Australian waters. The best-known class, to which all the edible species of crustacean belong, is Malacostraca. The warm waters of northern Australia are home to many species of decapod crustaceans, including crabs, false crabs, hermit crabs, lobsters, shrimps, and prawns. The peracarids, including the amphipods and isopods, are more diverse in the colder waters of southern Australia. Less-well-known marine groups include the
On the Origin of Species an incipient species" and that "species are only strongly marked and permanent varieties". He argues for the ubiquity of variation in nature. Historians have noted that naturalists had long been aware that the individuals of a species differed from one another, but had generally considered such variations to be limited and unimportant deviations from the archetype of each species, that archetype being a fixed ideal in the mind of God. Darwin and Wallace made variation among individuals of the same species central to understanding the natural world. In Chapter III, Darwin asks how varieties "which I have called incipient species"