Highlights from the Natural Sciences Collections of the Museum and Art Gallery of the Northern Territory, Australia
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.
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.
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.
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.
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.
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.
Gavin Dally, Senior Collections Manager, Natural Sciences, MAGNT
Michael Barritt, Engagement Co-ordinator, MAGNT
Michael Hammer, Curator of Fishes, MAGNT