2016

Natural History of the Northern Territory, Australia

Museum & Art Gallery of the Northern Territory (MAGNT)

Highlights from the Natural Sciences Collections of the Museum and Art Gallery of the Northern Territory, Australia

The Museum and Art Gallery of the Northern Territory (MAGNT)
The MAGNT is located in Darwin, the capital city of the Northern Territory of Australia. Our extensive Natural Sciences collections of animal, mineral and fossil specimens, from locations ranging from the interior deserts to the tropical northern Australian seas, represent the broad animal diversity found in the region. They are a permanent and accessible resource for scientific investigations into biodiversity and a basis for public exhibitions and education.
Meet Sweetheart
Sweetheart, a 5.1 metre long male Estuarine Crocodile (Crocodylus porosus), is an iconic part of the history of the Northern Territory and our most popular exhibit. In the 1970's, Sweetheart gained notoriety for attacking small boats at Sweets Lookout billabong, a local fishing spot. By 1979 he had become quite aggressive and it was decided to capture and relocate him to a crocodile farm before he hurt anyone. Unfortunately he became entangled with a sunken tree and drowned during the capture process. His body was presented to the Museum and Art Gallery of the Northern Territory, where he was prepared by a taxidermist as a skin mount and also a skeleton.

Sweetheart's skeleton. A crocodile's skin cannot be neatly separated from the skull, so Sweetheart's skull remains in the skin mount. A similar sized skull from another crocodile that died naturally was used to complete this skeleton.

The skull has a large fracture through the lower jaw. This partially healed but probably affected the crocodile’s ability to hunt and contributed to his death.

Osteoderms are the bony plates found within the dermal layers of a crocodiles skin. These osteoderms, from the Australian Freshwater Crocodile (Crocodylus johnstoni), have been laid out with the skull to show their arrangement over the body. The osteoderms create a highly armoured, protective skin and also act as heat exchangers to control body temperature.

Wall of Fishes
Fishes are the most diverse of all the vertebrate animal groups. There are over 400 species of fishes in Darwin Harbour alone. A selection of regionally occurring fish species have been cast in fibreglass for display in the Natural History Gallery.

The Barramundi (Lates calcarifer) grows to over 55kg. They mature initially as males and will spawn for one or two seasons before undergoing a sexual inversion, and becoming females for the next breeding season.

The Narrow Sawfish (Anoxypristis cuspidata) grows to about 3.5 metres in length and is mostly marine, but does occur in tropical river estuaries. Sawfish are threatened world-wide by fishing, as they are often incidentally caught and killed by trawlers and gill-netters. Due to their low birth-rate, and the threat from fishing, sawfish are listed as endangered species in Australia.

Sawfish feed by slashing into a school of fish with their sharp-toothed snout, then picking up the remains.

The Spinner Shark (Carcharhinus brevipinna) is an active species and often leaps out of the water, rotating up to three times before falling back in. They are found in warmer waters around the world and can form large schools.

Black Marlin (Makaira indica) are large predators, which have the upper jaw greatly lengthened and spear-like. They use their strong bony bills to hit and stun their prey, which includes many kinds of schooling fish.

Giant Groupers (Epinephulus lanceolatus) can grow to nearly 4 metres long and weigh over 270 kg. These solitary, large fish are fearless and may show curiosity towards boats and divers, often approaching very close.

Great Barracuda (Sphyraena barracuda) are a large predatory fish found in tropical and sub-tropical oceans around the world. They are known to carry ciguatera poison, a toxin produced by a microscopic dinoflagellate organism that accumulates in predatory fish. Eating an infected fish can cause severe illness.

The Giant Hammerhead's (Sphyrna mokarran) unusual head shape might give the shark extra lift and manoeuverability, or allow it to see more efficiently. Hammerheads may form large schools of up to 100 individuals.

Remoras use their sucking disc to attach themselves to a range of marine hosts. The shark provides transport and protection from other predators for the remora, which keeps its host clean of parasites.

Thunderbird
Thunderbirds are an Australian family of extinct, giant flightless birds that are thought to be distantly related to geese. This specimen, known as Bullockornis planei, stood 2.5 metres tall and weighed over 250 kg and is a common fossil at the 12 million year old Bullock Creek fossil site in the Northern Territory of Australia.

Due to their massive beaks, Thunderbirds were once thought to be carnivorous predators. There is now strong evidence, such as a lack of claws, that indicates they were probably plant-eating herbivores.

Marsupial 'Rhinoceros'
The 300 kg Marsupial 'Rhinoceros' (Neohelos stirtoni) was one of the large, browsing herbivores that roamed parts of Australia some 12 million years ago, during the Miocene epoch. Well preserved fossilised bones from this, and other extinct species, are found at the Bullock Creek fossil deposit in the Northern Territory of Australia. Descendants of Neohelos stirtoni gradually became even larger in size, culminating in a species that grew to over 700kg (Diprotodon optatum). As humans dispersed across the world, these megafauna species were hunted which may have played a major role in their extinction.

Neohelos was a diprotodontid, meaning 'two forward teeth'. A herbivore that browsed on shrubs and trees, Neohelos had wide molar teeth for grinding down plant fibre. Sharp front incisor teeth help to tear and cut through plants.

Bullock Creek limestone is fossil-rich. Acetic acid is used to dissolve the rock and expose the fossils. Fossils indicated are:
1. Marsupial 'rhinoceros' lower jaw bone
2. Baru crocodile lower jaw fragment
3. Thunderbird 'Giant Goose' lower leg bone

Australian Ichythyosaur fossil
A partial reconstruction of the 7 metre long fossilised Australian Ichthyosaur (Platypterygius longmani), based on several individuals from the 110 million year old Darwin Formation fossil beds and Queensland localities. Ichthyosaurs were air-breathing marine reptiles that resembled both modern fish and dolphins and gave birth to live young. They thrived in the inland sea that covered vast areas of Australia during the Cretaceous period, some 120-90 million years ago.
White-bellied Sea Eagle
White-bellied Sea Eagles (Haliaeetus leucogaster) are a common sight in coastal and near coastal areas around Australia. They can be observed perched high in a tree or soaring over waterways and adjacent land, looking for prey. As a highly skilled hunter, they feed mainly on fish, turtles and snakes but will readily also take birds and mammals.
Arnhem Leaf-nosed Bat
The Arnhem Leaf-nosed Bat (Hipposideros inornatus) is an insectivorous microbat that is known from only a few localities. It roosts in caves in very remote sandstone escarpment country in western Arnhem Land, in the Northern Territory of Australia. At night it forages for food such as beetles, moths and cockroaches in nearby vegetated areas.
Thorny Devil
The Thorny Devil (Moloch horridus) is an unmistakable type of dragon lizard. They can be observed slowly, and somewhat awkwardly, moving about sand and spinifex country in the arid areas of central and western Australia. Thorny Devils thrive on a diet of exclusively small black ants and will sit next to an ant trail all day, eating thousands of individuals.

The knob growing on the back of the neck acts as a 'false head' to confuse predators, while desert camouflage colouration and intimidating spiny body armour provide further protection.

Great Bowerbird
Great Bowerbirds (Ptilonorhynchus nuchalis) have highly evolved, complex courtship behaviour that involves the building and decoration of bowers. Males design and construct these elaborate structures to court females. The bowers are open or over-arching avenues of twigs and grass, aligned north-south. The floor and entrances are decorated with pale-coloured ornaments such as shells, bones, stones, glass and fruit. The walls of the bower may be painted with a mixture of saliva and plant material. Mating takes place in the bower. Females build a separate nest and rear the young on their own.

A male Great Bowerbird will use his decorated bower to attract mates for many years.

Southern Marsupial Mole
Southern Marsupial Moles (Notoryctes typhlops) are very distinctive animals with no external eyes or ears and silky golden fur. They are very well adapted for living underground. Their front legs are short and possess two enlarged spade-like claws and their marsupial pouch faces backwards. They dig temporary tunnels in the slopes and tops of sand dunes in the central Australian desert. They are carnivores and survive on a diet of insects such as ants and termites.
Plains Death Adder
The Plains Death Adder (Acanthophis hawkei) is found on the flat, treeless cracking-soil plains of northern Australia, where it is a major predator of frogs, reptiles and rats. Like all Death Adders, they are highly venomous and wait in hiding until their prey comes near. To attract prey to within striking distance, this species undulates its specially modified tail-tip to imitate a defenceless insect.
Rainbow Bee-eater
The Rainbow Bee-eater (Merops ornatus) is found throughout mainland Australia, except for in the desert areas. They are highly skilled at catching flying insects on the wing before carrying them back to a perch to eat. A breeding pair will dig a long tunnel into a sandy bank to use as a nest and raise their young.
Estuarine Stonefish
Considered to be the most venomous of fishes, a sting from the Estaurine Stonefish (Synanceia horrida) can be agonising. They are superbly camouflaged to match their surroundings and can be extremely difficult to see.

There are 13 stout dorsal spines, each of which are capable of injecting a very toxic venom. A Stonefish antivenom has been developed, which reduces the likelihood of death following a sting.

A sheath of thick skin normally covers each spine. At the base of each spine are two venom glands that dispense their contents along a groove in the spine.

Nankeen Kestrel
The Nankeen Kestrel (Falco cenchroides) is the smallest falcon in Australia and one of the most commonly seen. They prefer open country such as grasslands and avoid dense forests. Small prey items such as lizards and insects may be eaten while flying but larger kills like rodents are taken back to a perch to consume.
Northern Quoll
Often referred to as a native cat, Northern Quolls (Dasyurus hallucatus) are in fact aggressive, carnivorous marsupials, found only in the northern parts of Australia. Males live for about a year and once they have mated will quickly die. The females can live for up to 3 years and care for up to 8 young alone. Since the arrival of the highly toxic feral Cane Toad in Australia, Northern Quolls have disappeared from many parts of their natural range.
Blue-winged Kookaburra
The brightly coloured Blue-winged Kookaburra (Dacelo leachii) is a type of kingfisher, a carnivorous bird found only in northern Australia and New Guinea. They are efficient hunters, diving down onto their prey and then often beating their capture to death on a tree branch. Their loud and raucous call enables an observer to easily spot them in the wild.
Frilled Lizard
The spectacular frill of the Frilled Lizard (Chlamydosaurus kingii) is probably the largest body ornament, relative to size, of any animal. Normally neatly folded over the neck and shoulders, the frill is erected by special bones and cartilage in the throat. It is used in formidable threat displays. When threatened, Frilled Lizards stand upright, open their mouth and spread their frill, and may even leap at predators. Males defending their territories will wave the frill, head-bob and lash their tail. Frilled Lizards live on trees and come down to the ground most often during the wet season. On the ground they are one of the few animals that regularly walk on their hind legs.
Chestnut Rail
The Chestnut Rail (Eulabeornis castaneoventris) lives only in the mangroves of northern Australia and the Aru Islands of Indonesia. They are wary birds and are more often heard than seen. They are territorial and hunt at low tide for small crabs and molluscs that live on the mud surface. Some Chestnut Rails use a hammerstone or anvil to break open the strong shells of their prey. A small pile or midden of broken shells is an indication of the bird's feeding activities.
Sugar Gliders
Sugar Gliders (Petaurus breviceps) have thin membranes of loose, furry skin between their wrists and ankles that enable them to glide. They launch themselves from tree trunks and branches and 'fly' by stretching their limbs, causing the gliding membranes to spread. These small possums can glide at least 50 metres and steer by changing the curve of the membranes. This gliding ability allows Sugar Gliders to easily move between food-bearing trees and also helps them to escape predators such as owls, snakes and feral cats. Active at night, Sugar Gliders usually live in small family groups and nest in tree hollows. They feed on insects, fruit and tree sap or gum.
Brahminy Kite
Found in coastal areas of northern and eastern Australia, the Brahminy Kite (Haliastur indus) can be seen performing aerial acrobatics during their mating displays. As a type of raptor (bird of prey), they feed on a variety of insects, fish and other small animals. They are expert at stealing from other fish-hunting birds by snatching prey in flight.
Water Python and Grassland Melomys
A major predator on the tropical floodplains in Australia is the Water Python (Liasis fuscus). These big non-venomous snakes occur in large numbers. During the dry season they hide among vegetation and emerge at night to hunt rats, such as the Grassland Melomys (Melomys burtoni). Immense numbers of rats live among the cracks in the earth of the dried floodplains. During the wet season, when the rats are absent from the swamped floodplain, the pythons become more aquatic and switch their diet to water birds and their eggs. This ability to change behaviour with the seasons is why many floodplain animals are very successful at survival.
Wedge-tailed Eagle
The Wedge-tailed Eagle (Aquila audax) is Australia's largest bird of prey and is the official bird emblem for the Northern Territory. It has a wingspan of up to 2.5 metres and is able to soar at high altitudes effortlessly for hours on end. Breeding pairs are territorial and live in the one area throughout the year, defending around their nest sites from other Wedge-tailed Eagles. They are excellent hunters of live prey but will also readily feed on fresh roadkill and other carcasses.
Greater Bilby
The Greater Bilby (Macrotis lagotis) is a rabbit-sized marsupial that was once widespread across semi-arid and arid Australia. Due to predation by introduced predators such as foxes and cats, they are now reduced to small, scattered populations in the most remote arid areas. During the day, Greater Bilbies shelter in long and deep burrows that they dig. At night they will venture out to feed on insects, tubers, seeds and fungi by digging holes in the dirt.
Magpie Goose
The Magpie Goose (Anseranas semipalmata) thrives in large flocks on the floodplains of the Northern Territory in Australia. During the wet season, male geese join with one or two females to build a floating platform. These are made by trampling reeds, and are used for courtship and resting. When a female is ready to lay eggs, they modify the platform into a floating bowl-like nest. Both the male and females share incubation, and often stand over the eggs to shade them from the hot sun. The chicks are well developed upon hatching. They spend only a day in the nest before venturing out with their parents to search for food. As the dry season progresses, the geese move from one drying swamp to another.
Water Rat
Water Rats (Hydromys chrysogaster) are unusual rodents because of their aquatic lifestyle. They have small eyes and ears, large webbed hind feet and soft, waterproof fur. They are excellent swimmers and divers and are most active at night. Water Rats spend the day sheltering in burrows dug in river and lake banks. Unlike most other rats, they are predators and are particularly partial to aquatic prey. They find most of their food underwater, and feed on crabs, crayfish, frogs, small turtles, mussels, young birds and large insects.
Short-beaked Echidna
The Short-beaked Echidna (Tachyglossus aculeatus) grows up to 44 cm long and has a rounded body that is covered in sharp spines, with fur in between. They are an unusual type of egg-laying mammal known as a monotreme that are only found in Australia and New Guinea. Echidnas are shy and move slowly and carefully but when disturbed they will quickly dig into the ground, leaving only their protective spines exposed.

Echidnas are adapted for digging, with their long claws and sturdy limbs. The claws on the hind feet curve backwards to enable cleaning between the spines. Their long snouts help them probe into ant nests.

Green Turtle skeleton
Green Turtles (Chelonia mydas) can be quite common along the tropical northern Australian coastline. Adults can be seen feeding in seagrass meadows in shallow water. They lay up to 100 eggs per season, when they come ashore on sandy beaches to dig their nests.
False Killer Whale skull
False Killer Whales (Pseudorca crassidens) belong to the oceanic dolphin family. Their long, slender bodies attain a maximum size of nearly 6 metres in length and they live in tropical and subtropical oceanic waters around the world. They are a difficult animal to study in the wild and much that we know about them comes from washed-up bones and skulls such as the specimen pictured here.
Barramundi skeleton
The Barramundi (Lates calcarifer) can grow to over 55 kgs and is found throughout the Indo-West Pacific, including northern Australia. They are protandrous hermaphrodites, which means they change sex from male to female during their lifetimes. After spawning several times as a mature male, the Barramundi moves from freshwater habitats to saltwater river mouths, triggering a change in sex. They are a popular angling and eating species in the tropics.
Atlas Moth
The Atlas Moth (Attacus wardi) is a large, spectacular insect with a wingspan of about 17cm. It is not commonly encountered and is only known from seven locations in northern Australia. It has quite specific habitat requirements and is restricted to coastal monsoon rainforests.

Cathedral termite mounds are built by Spinifex Termites (Nasutitermes triodiae), which are social insects, living as a colony within each mound. The mounds are built with soil, termite saliva and droppings. Within the mound, worker termites create a network of passages and food-storage and living chambers. Mounds can reach up to 7 metres in height and may remain for as long as 80 years.

Spinifex Termites feed on harvested dead grass and spinifex, which is stored in large amounts in cells within the mound. They eat as much grass as large herds of grazing mammals do in other parts of the world.

Witchetty Moth
Witchetty Moths (Endoxyla leucomochla) produce a fat, white caterpillar or grub. The grub eats into the woody roots of the Witchetty bush, feeding on the root sap until it reaches a length of about 7 cm. After pupating, the adult moth emerges with a wingspan of about 16 cm. It lacks any functional feeding organs and lives for a few days on its fat reserves before breeding and then dying.
Spaghetti Worm
The Spaghetti Worm (Loimia ochracea) is just one of the many thousands of different species of polychaete worms that live in the ocean. This species is about  2-3 cm in length and lives in a buried tube that it constructs from sand. It spreads its white tentacles over the sandy sea floor to draw in food particles to its mouth. The tentacles contain chemical compounds that make them unpalatable to fish.

The red structures are external gills that draw dissolved oxygen from the water, enabling the worm to breathe.

Giant Timor Sea Hermit Crab
The Giant Timor Sea Hermit Crab (Tisea grandis) is the largest of the marine hermit crabs and is found in the Timor Sea to the north of Australia. Like most hermit crabs it has a long, soft, spirally curved abdomen (not visible in this image) instead of the hard, calcified abdomen seen in related crustaceans. The vulnerable abdomen is protected from predators by a salvaged empty seashell carried by the hermit crab, into which its whole body can retract. As the hermit crab grows it must find a larger shell to move into and abandons the previous one.

Box Jellyfish (Chironex fleckeri) have numerous tentacles hanging from each corner of the body that contain thousands of minute stinging cells called nematocysts. These are so tiny that 1000 would fit on the head of a pin. Nematocysts contain a hollow thread that can spring out, pierce the skin of the prey, and inject venom. The venom is used to kill the small fish and prawns that the jellyfish feeds upon. The venom also affects humans, and large stings can cause serious injuries or even death. Box Jellyfish are common along the northern Australian coast between October and May.

Giant Clam
Giant Clams (Tridacna gigas) are the largest living bivalve molluscs. A pair of shells can reach a weight of 260 kg and a length of 1.4 metres. Giant Clams live in shallow water on coral reefs. They rest with their shells partially open, so that their body tissues are exposed to light. Giant Clams farm colonies of microscopic organisms (zooxanthellae) in the tissues that line their shells. They also have lense-like organs in their outer skin (mantle) which allows sunlight to reach the zooxanthellae. These organisms provide some of the nutrients needed by the clam to survive.

The Wedding Cake Venus Clam (Bassina disjecta) created great demand from collectors after it was first brought from Tasmania to Europe in the early 19th century.

The shell of the Chambered Nautilus (Nautilus pompilius) is secreted by a cephalopod and it is an ancient relative of octopuses and squid. Internally, the nautilus shell represents a mathematical spiral.

The Geography Cone Snail (Conus geographus) grows up to 15 cm long and has a tiny hypodermic dart to deliver its very potent toxin. It can rapidly kill fish; unfortunately an accidental sting to a human can also be fatal.

At over 1 metre in length, the False Trumpet Snail (Syrinx aruanus) is the largest marine snail in the world. It is found along the coast of the Northern Territory in Australia, as well as the Kimberley coast of Western Australia and the southern coast of Papua New Guinea.

Juvenile False Trumpets have a high, multi-whorled shell when they first hatch, but the top part of the shell falls off when they mature. Therefore, juveniles could easily be mistaken for a different species.

The Precious Wentletrap (Epitonium scalare) was first seen in Europe in the 17th century when traders brought specimens back from Ambon and the other Spice Islands. So rare and valuable was it 200 years ago that the Japanese made rice paper copies of it. These copies are now rarer than the actual shell!

The Manus Island Green Tree Snail (Papustyla pulcherrima) occurs only on the island of Manus, off the northern coast of Papua New Guinea. It has been massively over-collected and it is the only land snail from Papua New Guinea to be listed on the international CITES schedule which completely prevents its trade or export.

Credits: Story

Gavin Dally, Senior Collections Manager, Natural Sciences, MAGNT

Photography:
Michael Barritt, Engagement Co-ordinator, MAGNT
Michael Hammer, Curator of Fishes, MAGNT


Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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