The São Tomé collared fruit bat (''Myonycteris brachycephala'') is a species of

megabat Megabats constitute the Family (biology), family Pteropodidae of the Order (biology), order Chiroptera. They are also called fruit bats, Old World fruit bats, or—especially the genus, genera ''Acerodon'' and ''Pteropus''—Pteropus, flyin ...

in the family Pteropodidae. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

São Tomé and Príncipe São Tomé and Príncipe, officially the Democratic Republic of São Tomé and Príncipe, is an island country in the Gulf of Guinea, off the western equatorial coast of Central Africa. It consists of two archipelagos around the two main isla ...

. Its natural habitats are subtropical or tropical moist and

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

. It is threatened by

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

. This bat is unique in that it is the only known mammal where the whole population has an asymmetrical

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

Description

Notably, the entire species has an asymmetrical dental formula. All of the bats have one fewer lower internal

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

than would be expected. It is believed that the missing tooth is a

neutral mutation Neutral mutations are changes in DNA sequence that are neither beneficial nor detrimental to the ability of an organism to survive and reproduce. In population genetics, mutations in which natural selection does not affect the spread of the mutatio ...

that neither helps nor hurts the survival of individuals. The

founder effect In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, us ...

has been proposed as an explanation as to why the entire species is missing the lower incisor.Juste, J., & Ibáñez, C. (1993). An asymmetric dental formula in a mammal, the Sao Tomé Island fruit bat ''Myonycteris brachycephala'' (Mammalia: Megachiroptera). Canadian journal of zoology, 71(1), 221-224.

Distribution and habitat

This fruit bat is

to the higher parts of

São Tomé Island São Tomé Island, at , is the largest island of São Tomé and Príncipe and is home in May 2018 to about 193,380 or 96% of the nation's population. The island is divided into six districts of São Tomé and Príncipe, districts. It is located ...

, a volcanic island in the

Gulf of Guinea The Gulf of Guinea (French language, French: ''Golfe de Guinée''; Spanish language, Spanish: ''Golfo de Guinea''; Portuguese language, Portuguese: ''Golfo da Guiné'') is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez i ...

. No bat colonies have ever been found, and individual bats have been recorded from just three locations, at altitudes between above sea level. Its typical habitats include moist tropical montane forest at 1300 metres, moist forest at 800 metres with patchy remnants of the natural forest, and tropical lowland forest. It has also been recorded from cocoa plantations but seems to avoid the coastal region and the drier north part of the island.

Status

The São Tomé collared fruit bat has a restricted range, with a total area of occupancy of less than . There is a continuing decline in the quantity and quality of the forest on the island as tree felling takes place and the land is converted for agricultural use. Recent surveys of the island have failed to locate any of these bats and it seems to be a naturally rare species. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

has rated its conservation status as being "

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

References

{{DEFAULTSORT:Sao Tome Collared Fruit Bat Endemic mammals of São Tomé and Príncipe Fauna of São Tomé Island Myonycteris Mammals described in 1889 Taxa named by José Vicente Barbosa du Bocage Taxonomy articles created by Polbot