Australia animals

Main article: Fish in Australia
The Murray cod is Australia's largest wholly freshwater bony fish.^[124]
More than 5000 species of fish inhabit Australia's waterways;^[125][126] of these, 24% are endemic. However, because of the relative scarcity of freshwater waterways, Australia has only about 300 species of freshwater fish.^[127] Two families of freshwater fish have ancient origins: the arowana or bonytongues, and the Queensland lungfish.^[128] The Queensland lungfish is the most primitive of the lungfish, having evolved before Australia separated from Gondwana.^[127][129] One of the smallest freshwater fish, peculiar to the southwest of Western Australia, is the salamanderfish, which can survive desiccation in the dry season by burrowing into mud.^[130] Other families with a potentially Gondwanan origin include the Retropinnidae, Galaxiidae, Aplochitonidae and Percichthyidae.^{[citation needed]} Apart from the ancient freshwater species, 70% of Australia's freshwater fish have affinities with tropical Indo-Pacific marine species that have adapted to freshwater.^[131] These species include freshwater lampreys,^[132] Herrings, catfish, rainbowfish, and some 50 species of gudgeon, including the sleepy cod.^[133] Native freshwater game fish include the barramundi,^[134] Murray cod, and golden perch.^[135] Two species of endangered freshwater shark are found in the Northern Territory.^{[citation needed]}
The weedy sea dragon, a fish related to pipefish and seahorses, is found in the waters around southern Australia.^[136]
Several exotic freshwater fish species, including brown, brook and rainbow trout, Atlantic and Chinook salmon, redfin perch, common carp, and mosquitofish, have been introduced to Australian waterways.^[137] The mosquitofish is a particularly aggressive species known for harassing and nipping the fins of other fish. It has been linked to declines and localised extirpations of several small native fish species. The introduced trout species have had serious negative impacts on a number of upland native fish species including trout cod, Macquarie perch and mountain galaxias species as well as other upland fauna such as the spotted tree frog. The common carp is strongly implicated in the dramatic loss in waterweed, decline of small native fish species and permanently elevated levels of turbidity in the Murray-Darling Basin of south west Australia.^{[citation needed]}
Most of Australia's fish species are marine, and 75% live in tropical marine environments.^[126] This is partly due to Australia's huge marine territory, covering 9 million km².^[126] Groups of interest include the moray eels and squirrelfish,^[138] as well as the pipefish and seahorses,^[139] whose males incubate their partner's eggs in a specialised pouch.^[136] There are 80 species of grouper in Australian waters,^{[citation needed]} including one of the world's biggest bony fish, the giant grouper, which can grow as large as 2.7 m and weigh up to 400 kg.^[140] The trevally, a group of 50 species of silver schooling fish, and the snappers are popular species for commercial fishing.^[141] The Great Barrier Reef supports a huge variety of small- and medium-sized reef fish, including the damselfish, butterflyfish, angelfish,^[142] gobies, cardinalfish, wrassees,^[143] triggerfish and surgeonfish.^[144] There are several venomous fish, among them several species of stonefish and pufferfish and the red lionfish, all of which have toxins that can kill humans.^[145] There are 11 venomous species of stingray,^{[citation needed]} the largest of which is the smooth stingray.^[146] The barracudas are one of the reef's largest species.^[147] However, large reef fish should not be eaten for fear of ciguatera poisoning.
The spotted wobbegong is the largest wobbegong shark, reaching a length of around 3 m^[148]
Sharks inhabit all the coastal waters and estuarine habitats of Australia's coast. There are 166 species, including 30 species of requiem shark, 32 of catshark, six of wobbegong shark, and 40 of dogfish shark.^{[citation needed]} There are three species from the family Heterodontidae: the Port Jackson shark, the zebra bullhead shark and the crested bullhead shark.^[149] In 2004, there were 12 unprovoked shark attacks in Australia, of which two were fatal.^[150] Only 3 species of shark pose a significant threat to humans: the bull shark, the tiger shark and the great white shark. Some popular beaches in Queensland and New South Wales are protected by shark netting, a method that has reduced the population of both dangerous and harmless shark species through accidental entanglement.^{[citation needed]} The overfishing of sharks has also significantly reduced shark numbers in Australian waters, and several species are now endangered.^{[citation needed]} A megamouth shark was found on a Perth beach in 1988;^[151] very little is known about this species, but this discovery may indicate the presence of the species in Australian coastal waters.
Invertebrates[edit]
Of the estimated 200,000 animal species in Australia, about 96% are invertebrates. While the full extent of invertebrate diversity is uncertain, 90% of insects and molluscs are considered endemic.^[152] Invertebrates occupy many ecological niches and are important in all ecosystems as decomposers,^[154] pollinators, and food sources.^[155] The largest group of invertebrates is the insects, comprising 75% of Australia's known species of animals. The most diverse insect orders are the Coleoptera, with 28,200 species of beetles and weevils,^[156] the Lepidoptera with 20,816 species^{[citation needed]} including butterflies and moths,^[157] and around 14,800 species of Hymenoptera,^[158] including the ants, bees and wasps. Order Diptera, which includes the flies and mosquitoes, comprises 7,786 species.^[159] Order Hemiptera, including bugs, aphids and hoppers,^[160] comprises 5,650 species; and there are 2,827 species^{[citation needed]} of order Orthoptera, including grasshoppers, crickets and katydids.^[161] Introduced species that pose a significant threat to native species include the European wasp,^[162] the red fire ant,^[163] the yellow crazy ant^[164] and feral honeybees which compete with native bees.^[165]
There are 1,275 described species and subspecies of ant from Australia.^[166] These green ants (Oecophylla smaragdina) are found in tropical Australia and build nests in leaves.^[167]
Australia has a wide variety of arachnids, including 78 spider families^[168] with 79 species of spider familiar enough to have common names. There are numerous highly venomous species, including the notorious Sydney funnel-web and allied mygalomorphs, whose bites can be deadly.^[169] The redback spider was thought to be deadly but redback bites are no longer thought to be life-threatening, as the lack of deaths since 1956 was thought to be due to the development of an anti-venom which has since been shown to be no better than placebo.^[170][171] There are thousands of species of mites and ticks from the subclass Acari.^[172] Australia also has at least 150 species of pseudoscorpion with an estimated 550 more waiting to be described,^[173] and at least 17 scorpion genera with 120 species.^[174]
In the Annelida (sub)class Oligochaeta there are many families of aquatic worms, and for native terrestrial worms: the Enchytraeidae (pot worms) and the "true" earthworms in families Acanthodrilidae, Octochaetidae and Megascolecidae.^{[citation needed]} The latter includes the world's largest earthworm, the giant Gippsland earthworm, found only in Gippsland, Victoria.^[175] On average they reach 80 cm in length, but specimens up to 3.7 m in length have been found.^{[citation needed]}
The wolf spider, Lycosa godeffroyi, is common in many areas of Australia. In this family of spiders, the female carries her egg-sac.
The large family Parastacidae includes 124 species of Australian freshwater crayfish.^{[citation needed]} These include the world's smallest crayfish, the swamp crayfish, which does not exceed 30 mm in length,^[176] and the world's largest crayfish, the Tasmanian giant freshwater crayfish,^[177] measuring up to 76 cm long and weighing 4.5 kg.^[178] The crayfish genus Cherax includes the common yabby,^[177] in addition to the farmed species marron and Queensland red claw. Species from the genus Engaeus, commonly known as the land crayfish, are also found in Australia. Engaeus species are not entirely aquatic, because they spend most of their lives living in burrows. Australia has seven species of freshwater crab from the genus Austrothelphusa. These crabs live burrowed into the banks of waterways and can plug their burrows, surviving through several years of drought. The extremely primitive freshwater mountain shrimp, found only in Tasmania, are a unique group, resembling species found in the fossil record from 200 MYA.
A magnificent sea anemone on the Great Barrier Reef, with an ocellaris clownfish.
A huge variety of marine invertebrates are found in Australian waters, with the Great Barrier Reef an important source of this diversity.^{[citation needed]} Families include the Porifera or sea sponges,^[179] the Cnidaria (includes the jellyfish, corals and sea anemones, comb jellies),^[180] the Echinodermata (includes the sea urchins, sea stars, brittle stars, sea cucumbers, the lamp shells)^[181] and the Mollusca (includes snails, slugs, limpets, squid, octopus, cockles, oysters, clams, and chitons).^[182] Venomous invertebrates include the box jellyfish, the blue-ringed octopus,^[183] and ten species of cone snail,^{[citation needed]} which can cause respiratory failure and death in humans.^[183] The crown-of-thorns starfish usually inhabits the reef at low densities. However, under conditions that are not yet well understood, they can reproduce to reach an unsustainable population density when coral is devoured at a rate faster than it can regenerate. This presents a serious reef management issue.^{[citation needed]} Other problematic marine invertebrates include the native species purple sea urchin and the white urchin, which have been able to take over marine habitats and form urchin barrens due to the over harvesting of their natural predators which include abalone and rock lobster.^{[citation needed]} 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.^{[citation needed]}
There are many unique marine crustaceans in Australian waters. The best-known class, to which all the edible species of crustacean belong, is Malacostraca.^{[citation needed]} 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.^{[citation needed]} Less-well-known marine groups include the classes Remipedia, Cephalocarida, Branchiopoda, Maxillopoda (which includes the barnacles, copepods and fish lice), and the Ostracoda.^[184] Notable species include the Tasmanian giant crab, the second largest crab species in the world,^[185] found in deep water, and weighing up to 13 kg,^[186] and the Australian spiny lobsters, such as the western rock lobster, which are distinct from other lobster species as they do not have claws.^[177]
Invasive species[edit]
The poisonous cane toad