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Date: 11/4/98
Time: 8:32:37 PM
Remote Name: 203.5.10.41
Lauren and Rebecca The classification of species can be a bit confusing since the more we find out about species we tend to change which group they belong to. As far as the 2 species of bilby that you mention are concerned it is as follows. The classification tree starts at the top and groups get smaller as you go down. A simple version is as follows :- Kingdom - Animal (cf plant) Phylum - Chordata or vertebrata - animals with backbones (cf no backbone such as worms and butterflies) Class - Mammalia - vertebrates that have hair and suckle their young with milk. (other classes are birds, reptiles, amphibians and fishes) The mammals are broken into 3 subclasses ie monotremes (egg laying mammals echidna and platypus); marsupials - mammals that have pouches in which most of the development of the young take place ie kangaroos, bandicoots, possums and gliders etc.)and placentals - mammals like us,elephants, rats and mice, dolphins, horses, cat, dogs etc. In placental mammals most of the development of the young occurs within the female body where nourishment is provide from the female via the placenta or umbilical cord - the bit that when you're born gets cut off and leaves you with a belly button ! Classes and subclasses are then further divided into smaller groups with similar characteristics called Orders. For example in the marsupials there are 2 Orders: 1. Polyprotodonta (which basically means lots of teeth in the upper and lower jaw) and 2. Diprotodonta (which also basically means having only a pair of enlarged incisor teeth seperated by a big gap from the rest of the teeth in both upper and lower jaws.) Orders are then divided again into Families (based on similar characteristics again)and marsupial families include Macropodidae (kangaroos and wallabies); Dasyuridae (carnivorous marsupials such as the Tasmanian devil, dunnarts, planigales,kowari,mulgara etc.);Phalangeridae (brushtail possums and cuscuses) etc.
Is it confusing you yet ? - it's confusing me typing into this very small box ! Bilbies used to be included in their own family and it was called Thylacomyidae (notice how all family names end with "-idae" (thats a rule when naming families). The more we have learnt about the relationship of bilbies to other bandicoots has tended to make us think that they are similar enough in many ways to be included in the bandicoot family -peramelidae (which includes all the bandicoots). Of course it doesn't get any simpler - we have created sub families and the bilbies are now considered to belong to the sub-family Thylacomyinae (all sub families end with "-inae). ie Family - Peramelidae (used to be Thylacomyidae) Subfamily - Thylacomyinae Within the families and subfamilies we get down to the genus level which is a grouping of animals that are all very similar in their general characteristics of form ie they look similar. Within each genus there may be lots of species, the last level down in the classification eg In the genus Macropus of the family macropodidae (kangaroos and wallabies) we have Macropus rufus (red kangaroo), Macropus giganteus (grey kangaroo), Macropus robustus (wallaroo or Euro), Macropus rufogriseus (red-necked wallaby), Macropus parryi (pretty-faced wallaby) etc. The thing about species grouping is that all of the mebers of a species group are capable of breeding with one another however in a genus grouping (ie all the kangaroos in the genus Macropus) Macropus rufus can't breed with Macropus giganteus etc, Also note in the naming that the genus always has a capital letter to start and the species starts without the capital letter (another rule in naming !) Eventually back to your rather simple question which I seem to have made very complicated - the 2 species of bilbies you mentioned belong to the same genus - Macrotis (which means big ears) however they can't breed with one another an so are regarded as separate species. One is called Macrotis lagotis ( greater bilby )and the other is called Macrotis leucura (lesser bilby). Unfortunately the lesser bilby has not been seen since 1931 and is now regarded as extinct.
Genus - Macrotis Species - lagotis - leucura If you want to look at examples of this system of classification most biology text books will give details. If you want to see how our mammals are classified a good book is the Australian Museum Complete book of Australian Mammals edited by Ronald Strahan. It also provides a very good cover of what our mammals are, where they are found, what they eat,conservation status etc and should be in most good book shops. Hope I haven't confused you too much.
Peter