Thyropteridaedisc-winged bats

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This family of neotropical bats contains one genus with two species. Their common name is derived from the suction cups found on the wrists and ankles of these animals. These bats roost, head-up, inside the smooth tubes formed as young banana or heliconia leaves unfurl. The suction cups allow these bats to stick to the walls of these leaves, protected from rain and hidden from predators. Since the leaves open in a matter of a few days, groups are forced to change roosts often. Generally, the whole group moves together from the old leaf to a new one.

Thyropterids are small bats with a long and slender snout. They have no noseleaf, but they do have small warts on their noses above their nostrils. They have an abrupt "forehead," that is, the crown of their head rises abruptly above their muzzle. Their ears are moderately large and funnel-shaped, and the other edge is attached near the angle of the mouth. A tragus is present. The wing membranes of members of this family extend unusually far down their legs, arising on their feet near the base of the claws. Most individuals are reddish brown or pale brown in color on the back, and whitish or brownish on the undersurface.

The premaxillae of thyropterids are complete, and their palatal branches isolate two palatal foramina. Thyropterids lack a postorbital process. The dental formula is 2/3, 1/1, 3/3, 3/3 = 38 and the molars are dilambdodont. There is a gap between the incisors and canines, and between the right and left incisors.

Perhaps the strangest feature of these bats is their relationship to the family Myzopodidae (the old world sucker-footed bats). Myzopodids are bats found only in the rainforests of far-off Madagascar. The myzopodids also have suction cups on their thumbs and roost in young, rolled leaves, but their suction cups are thought to be the result of an evolutionary convergence with the suction cups of thyropterids. Unfortunately, there is no fossil record for the thyropterids.

These bats feed exclusively on insects.

Technical characters

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.

Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. Adaptation, Diversity, and Ecology. WCB McGraw-Hill, Boston. xii+563pp.

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.

Vaughan, T. A., J. M. Ryan, N. J. Czaplewski. 2000. Mammalogy. Fourth Edition. Saunders College Publishing, Philadelphia. vii+565pp.

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.

Contributors

Bret Weinstein (author), University of Michigan-Ann Arbor, Phil Myers (author), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

bilateral symmetry

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.

chemical

uses smells or other chemicals to communicate

endothermic

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.

motile

having the capacity to move from one place to another.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate