Kha-nyou (Laonastes aenigmamus)

Described as recently as 2005, the mammals is the sole surviving member of an ancient group of rodents that was previously considered extinct for some 11 million years ^{(3) (4)}. Dubbed a ‘living fossil’, this enigmatic rodent has a somewhat squirrel-like appearance with stubby legs, an elongated head, small rounded ears and long, conspicuous whiskers. The compact body is covered in long, soft, dense fur that varies in colour from a dark grey to black, fading to a lighter colour on the underside. The male and female are very similar in appearance, although the male may have slightly longer hairs on the back of the head, down to the shoulders ⁽²⁾.

Also known as

Laotian rock rat.

Size

Head-body length: 21.2 - 28.5 cm ⁽²⁾

Tail length: 12.3 – 16.1 cm ⁽²⁾

Understandably, there is little information on the biology of this recently described species, and what is known is derived largely from conversations with local people ⁽²⁾. However, the mammals is thought to be nocturnal, and the morphology of its digestive organs and teeth suggests that vegetation constitutes most of its diet, although it may supplement this with insects ^{(1) (2)}. It is probably also quite docile, moving slowly over open ground, and it is known to give birth to a single infant ^{(2) (6)}.

The kha-nyou is only known from Khammouan Province in Lao People’s Democratic Republic (PDR) in south-east Asia. Most of the specimens of this little-known species were collected from the villages of Ban Mauang and Ban Doy in Thakhek District, although remains of the species were collected from owl pellets at Tam En in Hinboun District ⁽¹⁾.

The kha-nyou inhabits rocky areas in limestone karst formations ^{(1) (2) (5)}.

Classified as Endangered (EN) on the IUCN Red List ⁽¹⁾.

While the status of the mammals is not entirely clear, in the dry season local people target it for trapping, and subsequent sell it for food in local markets, where it is considered a delicacy. Given that female kha-nyous generally bear only one young at a time, the level of sustainable hunting is probably not high ⁽⁵⁾. Its karst habitat is fairly resilient to degradation; however, the more accessible areas are vulnerable to logging and firewood collection ^{(1) (6)}. As a result of these threats and its small range, estimated at no more than 5,000 square kilometres, the kha-nyou is thought to be undergoing a continuing decline ⁽¹⁾.

The kha-nyou is afforded some sanctuary in Phou Hin Poun National Protected Area (formerly known as Khammouan Limestone National Biodiversity Conservation Area); however, with little management in place in the protected areas, and so little known about this rare rodent, further research is needed to determine  its current status and conservation needs ^{(1) (5)}.

View information on this species at the UNEP World Conservation Monitoring Centre.

For more information on the kha-nyou, see:

• Jenkins, P.D., Kilpatrick, C.W., Robinson, M.F. and Timmins, R.J. (2005) Morphological and molecular investigations of a new family, genus and species of rodent (Mammalia: Rodentia: Hystricognatha) from Lao PDR. Systematics and Biodiversity, 2: 419-454.
• EDGE of Existence:
  http://www.edgeofexistence.org/mammals/species_info.php?id=1397

For more information on conservation in Lao PDR, see:

• Wildlife Conservation Society:
  http://www.wcs.org/where-we-work/asia/lao-pdr.aspx

Authenticated (10/09/2010) by Bill Robichaud.

Karst formation

An area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns.

Morphology

The visible or measurable characteristics of an organism.

1. IUCN Red List (May, 2010)
   http://www.iucnredlist.org/
2. Natural History Museum (May, 2010)
   http://www.nhm.ac.uk/nature-online/species-of-the-day/biodiversity/endangered-species/laonastes-aenigmamus/index.html
3. Dawson, M.R., Marivaux, L., Chuan-Kui, L., Beard, C. and Metais, G. (2006) Loanastes and the ‘Lazarus Effect’ in recent mammals. Science, 311: 1456-1458.
4. Huchon, D., Chevret, P., Jordan, U., Kilpatrick, C.W., Ranwez, V., Jenkins, P.D., Brosius, J. and Schmitz, J. (2007) Multiple molecular evidences for a living mammalian fossil. Proceedings of the National Academy of Sciences, 104: 7495-7499.
5. Robichaud, W. (2010) Pers. comm.
6. Jenkins, P.D., Kilpatrick, C.W., Robinson, M.F. and Timmins, R.J. (2005) Morphological and molecular investigations of a new family, genus and species of rodent (Mammalia: Rodentia: Hystricognatha) from Lao PDR. Systematics and Biodiversity, 2: 419-454.