The water rat (Hydromys chrysogaster) is an Australian native rodent, which is one of only two amphibious mammals found in Australia (the other being the platypus). The species lives in burrows on the banks of rivers, lakes and estuaries and feed on aquatic insects, fish, crustaceans, mussels, snails, frogs, birds' eggs and water birds. Water Rats have a body 231-370 mm in length, weigh 340-1,275 g and have a thick tail measuring around 242-345 mm. Water rats have webbed hind legs, waterproof fur, a flattened head, a long blunt nose, many whiskers and small ears and eyes. They are black to brown in colour with an orange to white belly. Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms (as opposed to folk taxonomy). ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Typical Classes Subphylum Urochordata - Tunicatas Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... Families Many, see text The order Rodentia is the most numerous of all the branches on the mammal family tree. ... Subfamilies See text Muridae is the largest family of mammals. ... In biology, binomial nomenclature is the formal method of naming species. ... Étienne Geoffroy Saint-Hilaire (April 15, 1772 - June 19, 1844) was a French naturalist who established the principle of unity of composition. He was born at Étampes, Seine-et-Oise, and studied at the college of Navarre, in Paris, where he studied natural philosophy under M. J. Brisson. ... 1804 was a leap year starting on Sunday (see link for calendar). ... Binomial name Ornithorhynchus anatinus (Shaw, 1799) The Platypus (Ornithorhynchus anatinus) is a small, half-aquatic mammal endemic to the eastern part of Australia, and one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young (the other four are echidnas). ... A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... The gram or gramme, symbol g, is a unit of mass. ...

Reference

Australian Museum