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The marsupial moles are rare and poorly understood burrowing mammals of the deserts of western Australia. There are thought to be two species: the Southern Marsupial Mole (Notoryctes typhlops or itjaritjari by Australian Aborigines), and the Northern Marsupial Mole (Notoryctes caurinus), so similar to one another that they cannot be reliably told apart in the field.

Marsupial moles spend most of their time underground, coming to the surface only occasionally, probably mostly after rains. They are blind, their eyes having become reduced to vestigal lenses under the skin, and they have no external ears, just a pair of tiny holes hidden under thick hair.

The head is cone-shaped, with a leathery shield over the muzzle, the body tubular, the tail a short, bald stub. They are between 12 and 16 cm long, weigh 40 to 60 grams, and are uniformly covered in fairly short, very fine pale cream to white hair with an iridescent golden sheen. Their pouch has evolved to face backwards so that it does not fill with sand.

Marsupial moles provide a remarkable example of convergent evolution, with moles generally, and with the golden moles of Africa in particular. Although only related to other moles in that all are mammals, the external similarity is an extraordinary reflection of the similar evolutionary paths they have followed.

For many years their place within the Marsupials was hotly debated, some workers regarding it as an offshoot of the Diprotodontia (the order to which most living marsupials belong), others noting similarities to a variety of other creatures, and making suggestions that, in hindsight, appear bizarre. A 1989 review of the early literature, slightly paraphrased, states:

When Stirling (1888) initially was unable to find the epipubic bones in Marsupial Moles, speculation was rife: the Marsupial Mole was a monotreme, it was the link between monotremes and marsupials, it had it closest affinities with the (placental) golden moles, it was convergent with edentatesMyrmecophagidae Megalonychidae Bradypodidae Dasypodidae The order Xenarthra is a group of placental mammals, extant today only in the Americas. The origins of the order can be traced back as far as the early Tertiary (about 60 million years ago, or only a, it was a polyprotodont diprotodont, and so on. [1]

The mystery was not helped by the complete silence of the fossil record. On the basis that marsupial moles have some characteristics in common with almost all other marsupials, they were eventually classified as an entirely separate orderOrder is one of the levels of scientific classification of organisms. Orders are grouped into classes and themselves contain families. The standard groupings of taxonomy from most general to most specific are: Domain Kingdom Phylum (animals); Division (pl: the Notoryctemorphia. Molecular level analysis in the early 1980sMillennia: 1st millennium 2nd millennium 3rd millennium Centuries: 19th century 20th century 21st century Decades: 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 2020s 2030s Years: 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 Events and trends showed that the marsupial moles are not closely related to any of the living marsupials, and that they appear to have followed a separate line of development for a very long time, at least 50 million years.

In 19851985 is a common year starting on Tuesday. Events January events January 1 Creation of the Internet's Domain Name System. January 17 British Telecom annouces they are going to abolish the famous red telephone boxes. January 23 A debate in the House of Lor, the vast newly discovered limestone fossil deposits at Riverseigh in northern QueenslandQueensland State flag ( In detail) Coat of Arms ( In detail) Capital Brisbane Governor HE Ms Quentin Bryce Premier Peter Beattie Area — Land — Marine — Total 1 730 648 km² 121 994 km² 1 852 642 km² Population (2002) Density 3 729 000 2. 15/km² Time zone U yielded a major surprise: marsupial mole fossils between 15 and 20 million years old, which were by no means identical to the living species but clearly related, and possibly even of a direct ancestor. In itself, the discovery of a MioceneThe Miocene Epoch is a period of time that extends from about 5 million to 24 million years before the present. As with other older geologic periods, the rock beds that define the start and end are well identified, but the exact dates of the start and end marsupial mole presented no great mysteries. Just like the modern forms, it had many of the features that are assumed to be adaptations for a life burrowing in desert sands, in particular the powerful, spadelike forelimbs. The Riversleigh fossil deposits, however, are from an environment that was not remotely desert-like: in the Miocene, the Riversleigh area was a tropical rainforestA rainforest is a forested biome with high annual rainfall. Some cite a minimum normal annual rainfall of 2500 mm (about 100 inches or 250 centimeters), with normal rainfall at least 60 mm during each of the twelve months of the year. Others set the minim.

One suggestion advanced was that the Miocene marsupial mole used its limbs for swimming rather than burrowing, but the mainstream view is that it probably specialised in burrowing through a thick layer of moss, roots, and fallen leaf litter on the rainforest floor, and thus, when the continent began its long, slow desertification, the marsupial moles were already equipped with the basic tools that they now use to burrow in the sand dunes of the Western Australian desert.