This family contains only one species, Craseonycteris thonglongyai. This species was first discovered and described in 1974. With its discovery, C. thonglongyai became the smallest known mammal, weighing only two grams at maturity. It is extremely rare, only having been observed in the Kwai river drainage in Thailand. Craseonycterids are thought to be most closely related to rhinopomatids and emballonurids but are distinct enough from both groups to warrant familial status.
Craseonycterids lack tails and calcars. Their wings are long and broad to aid in hovering. Their nose, which appears to be mounted on a raised platform and has slit-like, vertical nostrils, resembles that of a hog. These bats have large ears and traguses that appear swollen. Their uropatagium is long.
The skulls of craseonycterids lack postorbital processes. Their premaxillae are not fused to the surrounding bones, but they form a complete ring around the narial opening. The palate ends at the level of the last molars. The teeth are dilambdadont and the dental formula is 1/2, 1/1, 1/2, 3/3 = 28.
Craseonycteris thonglongyai roosts deep in limestone caves in loose groups of fewer than 20 individuals. Individuals are known to eat insects and spiders that are caught on the wing or gleaned from tree-top foliage. These bats are capable of hovering, an activity that may have led to selection for the small size of this species.
Not much is known about the reproduction and ecology of these rare animals, and no fossils have been discovered.
References and literature cited:
Anderson, S. and J. K. Jones, Jr., 1984. Orders and Families of Recent Mammals of the World. John Wiley and Sons, New York. 686pp.
Fenton, M. B., P. Racey, and J.M. V. Rayner (eds.), 1987. Recent Advances in the Study of Bats . Cambridge University Press, Cambridge.
Hill, J. E. and J. D. Smith, 1992. Bats: A Natural History . University of Texas Press, Austin.
Lawlor, T. 1979. Handbook to the Orders and Families of Living Mammals. Mad River Press.
Macdonald, D. (ed.). 1993. The Encyclopedia of Mammals. Facts on File Publications
Richarz, K. and A. Limbrunner. 1993. The World of Bats. Tropical Fish Hobbyist.
Wilson, D. E., and D. M. Reeder. 1993. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd edition. Smithsonian Institution Press, Washington. xviii+1206 pp.
Written by Bret Weinstein and Phil Myers; last updated 3 October 1997.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
having the capacity to move from one place to another.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate