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Ametrida centuriolittle white-shouldered bat

By Ashlee Sullivan

Geographic Range

White-shouldered bats, Ametrida centurio are found in Central America and parts of South America, including Venezuela, Guyana, Brazil, Trinidad, and Bonaire Island. They are rare throughout their range.

(Nowak, 1994)

Habitat

White-shouldered bats are found in moist tropical forests, especially near streams. They have been most commonly found in multistratal, tropical evergreen forests.

(Eisenburg, 1989; Emmons, 1990; Nowak, 1994; Reid, 1997)

Physical Description

White-shouldered bats exhibit sexual dimorphism in size. The genus Ametrida once included two species, A. centurio and A. minor, due to the size difference between sexes. Ametrida centurio were the larger females, averaging 12g and having a head and body length of 35-47mm, while Ametrida minor were the smaller males who weigh on average 8g with a head and body length smaller than that of the females. Forearm length ranges between 25 and 33 mm.

White-shouldered bats resemble other frugivorous leaf-nosed bats. They have the shortened face typical of frugivorous phyllostomids. These bats have about 32 teeth, and the small 3rd lower molar is present. They have no banding or striping on the face or back. White-shouldered bats gets their name from the light, almost white-colored, patches found on each shoulder. The color of the body ranges from sooty brown to a dark brown, almost gray color. Males tend to be more dusky with grayer tints than females.

The eyes of white-shouldered bats are relatively large. Ametrida centurio tend to have a yellow colored iris and males possess a swollen pad beneath each eye. They have no external tail but the long tail membrane is well haired and u-shaped with fringes along the edge.

(Eisenburg, 1989; Emmons, 1990)

  • Range mass
    7.8 to 12.6 g
    0.27 to 0.44 oz

Reproduction

Reproduction in A. centurio is not well understood. Females have been captured carrying a single embryo, suggesting that typically only one young is born.

(Emmons and Feer, 1990)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Behavior

Ametrida centurio is rare throughout its range and not well studied, there is no available literature on behavior in this species.

Communication and Perception

Food Habits

Little is known about the food habits of Ametrida centurio. They are probably primarily frugivorous, based on skull and dental structure, but may consume insects as well.

(Nowak, 1994; Reid, 1997)

Economic Importance for Humans: Positive

Frugivorous bats are sometimes beneficial because they incidentally pollinate flowers that are close to the fruit that they are consuming. Insectivorous bats benefit humans by reducing insect pest populations.

Economic Importance for Humans: Negative

There is no information regarding the negative impacts of these bats on the human population.

Conservation Status

Ametrida centurio is a poorly understood bat species. This lack of information, in addition to its rarity throughout its known range, suggests that this bat species should be studied more thoroughly to understand the risks it may face.

Other Comments

Future research of Ametrida centurio may give us a better understanding of their habits and behavior. Until then, little is known about this species of bats.

Contributors

Ashlee Sullivan (author), St. Lawrence University, Erika Barthelmess (editor), St. Lawrence University.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

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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.

native range

the area in which the animal is naturally found, the region in which it is endemic.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

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

tactile

uses touch to communicate

References

Eisenburg, J. 1989. Mammals of the Neotropics: The Northern Neotropics Vol. 1. Chicago: The University of Chicago Press.

Emmons, L., F. Feer. 1990. Neotropical Rainforest Mammals: A Field Guide. Chicago and London: The University of Chicago Press.

Nowak, R. 1994. Walker's Bats of the World. Baltimore and London: John Hopkins University Press.

Reid, F. 1997. A Feild Guide to The Mammals of Central American and Southeast Mexico. NY: Oxford University Press.

Yalden, D., P. Morris. 1975. The Lives of Bats. NY: The NY Times Book Co..

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