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)
Biogeographic Regions:
neotropical 
(native ).
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)
Terrestrial Biomes:
rainforest .
Physical Description
(0.27 to 0.44 oz; avg. 0.36 oz)
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)
Some key physical features:
endothermic ; bilateral symmetry .
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.
Key behaviors:
motile .
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: Negative
There is no information regarding the negative impacts of these bats on the human population.
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.
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
No special 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.
