Desert rat-kangaroo

It was formed like a kangaroo, but had the bulk of a small rabbit, and was described as having a delicate and slender form. The length of the head and body combined is estimated to be about in addition to a long tail. Its head was short, blunt, and wide, different from that of any kangaroo or wallaby A distinguishing feature of this species was the difference in size between the fore and hind limbs. Its fore limbs were quite delicate with bones weighing , while its hind limbs are large with bones weighing . This difference is related to saltation. Other characteristics related to hopping locomotion include a long, but rather thin tail. ==Distribution and habitat==

Caloprymnus campestris was thought to occupy a relatively small area in South Australia, extending just over the borders of southwestern Queensland and Northern Territory. It was last seen in 1935 in the eastern Lake Eyre basin of northern Southern Australia. The desert rat-kangaroo lived in the desert regions of Australia, including clay pans, loamy flats, sand ridges, and gibber plain habitats. Its native habitat was very arid; cover is sparse, and consists of saltbush and other chenopods and emu bush. ==Ecology and behaviour==

Caloprymnus campestris was solitary except for mothers with young offspring. It lived in nests built over shallow depressions in the ground. These nests were excavated or found and are crucial in the desert, where temperatures can be high, while relatively little brush or foliage is available for cover. The "pits" were lined with grass, which females carried to the nest with their tails. The nest would then be covered with twigs to provide cover from the scorching sun. Often, the desert rat kangaroo was found peeking out of the top of the nest to observe its surroundings. This species would spend most of the day taking cover in the nest, and emerge at dusk to feed. It was so independent of water, it even shunned the succulent plants on the sand hills. It was able to survive without any surface water while feeding on green plants. Locomotion It had a distinct method of hopping. Its posture was forward and the long tail was extended when it moved at high speeds. Unlike other marsupials, Caloprymnus would land with the right foot in front of the left foot. It showed great endurance while being chased on horseback at high speeds with Australian mammalogist Finlayson reported chasing an individual over , and "paused only to die". Reproduction Females reached sexual maturity at about 11 months, while males reached maturity some two months later. Marked sexual dimorphism was apparent, with females being larger. Females went through oestrus at three-week intervals and could mate throughout the year. Although able to mate all year, they had an irregular breeding season when most mating took place. Females with pouched joeys had been found between June and December. Young were born very undeveloped, as is typical of marsupials. Gestation was probably around one to two months, with a pouch period of two to three months. All females were found with only one young at a time. Young remained dependent for over a month after leaving the pouch and soon after would leave permanently. ==Rediscovery and extinction==

The desert rat-kangaroo was first recorded in the early 1840s. However, after these early sightings, it was no longer recorded for 90 years (aside from an unconfirmed report in 1878), and was widely believed to be extinct. Following the relief of drought conditions which improved the local habitat, the animal was rediscovered in 1931 when Hedley Finlayson found a thriving colony of them. Possible survival In view of its amazing recovery following a 90-year period when it was not seen, the extinction of the desert rat-kangaroo is not certain; thus, sightings of this animal would not fall into the cryptozoology category. In similar cases, the broad-faced potoroo was last seen in the late 19th century and is considered extinct, Gilbert's potoroo was considered extinct for 120 years prior to its rediscovery in 1994, and the long-footed potoroo was only discovered in 1967. The finding of recent remains in the 1980s casts some doubt on the extinction of this species. Professor Ronald Nowak stated in his 2005 book, "perhaps a small population still survives, awaiting the time when it again may increase in response to proper conditions." 2011 Peake Station sighting An animal was sighted in May 2011 off Peake Station and subsequently identified from a museum skin as a desert rat-kangaroo. The area was then surveyed in August the same year. An old nest with some small macropod like scats was found and some tracks were also found near a waterhole that might have been made by the desert rat-kangaroo. However DNA analysis of the scats failed to yield any usable DNA. No DNA was found in dingo and cat scats in the area as well. As such the sighting remains unconfirmed, but researchers Tony Robinson and Tiana Forrest confirmed the possibility "that a small population of Caloprymnus, generally considered to be extinct throughout its former range across the Lake Eyre Basin, may have been present in this area in May 2011". ==References==