The Egyptian fruit bat or Egyptian rousette (Rousettus aegyptiacus) is a species of megabat that is found in Africa, the Middle East, the Mediterranean, and the Indian subcontinent. It is one of three Rousettus species with an African-Malagasy range, though the only species of its genus found on continental Africa. The common ancestor of the three species colonized the region in the late Pliocene or early Pleistocene. The species is traditionally divided into six subspecies. It is considered a medium-sized megabat, with adults weighing and possessing wingspans of approximately . Individuals are dark brown or grayish brown, with their undersides paler than their backs.
The Egyptian fruit bat is a highly social species, usually living in colonies with thousands of other bats. It, along with other members of the genus Rousettus, are some of the only fruit bats to use echolocation, though a more primitive version than used by bats in other families. It has also developed a socially-complex vocalization system to communicate with conspecifics. The Egyptian fruit bat is a frugivore that consumes a variety of fruits depending on the season and local availability. Because of its consumption of commercially-grown fruits, the Egyptian fruit bat is considered a pest by farmers. It also acts as a pollinator and seed disperser for many species of trees and other plants.
Taxonomy and etymology
The Egyptian fruit bat was described as a new species in 1810 by French naturalist Étienne Geoffroy Saint-Hilaire, who gave it the name Pteropus egyptiacus. He later revised the specific epithet to ægyptiacus, given as 1812 or 1818. In 1870, John Edward Gray placed it in the now-defunct genus Eleutherura, treating the taxon as two species (E. unicolor and E. ægyptiaca). Danish mammalogist Knud Andersen was the first reviser of the taxon; he used Rousettus ægyptiacus and wrote that egyptiacus "may [...] be considered a slip or misprint corrected by the author himself".
In 1992, G. B. Corbet and J. E. Hill argued that Geoffroy's revision from egyptiacus to ægyptiacus was invalid according to the ICZN Code, and changed the name back to egyptiacus. The 1999 Mammalian Species review used egyptiacus as well. However, Geoffroy's revision was supported in 2001 by D. Kock. He notes that aegyptiacus was "accepted almost universally by the scientific community", emphasizing its use by Andersen in 1912. Kock argued that even if it was an unjustified emendation at first, it became a justified emendation through widespread use, as the use of aegyptiacus was undisputed until Corbet and Hill (the ICZN Code also mandates that use of "æ" become "ae", hence ægyptiacus is no longer in use). Kock also writes that since the Latin adjective for "Egyptian" is aegyptiacus, egyptiacus is a simple misspelling in the original description. The Agreement on the Conservation of Populations of European Bats was amended to use the specific name aegyptiacus in 2003. Books like Mammal Species of the World (2005) and Mammals of Africa (2013) follow Kock and use the name aegyptiacus.
Two other members of Rousettus have an African-Malagasy range: the Madagascan rousette (R. madagascariensis) and the Comoro rousette (R. obliviosus). Based on an analysis of both mitochondrial and nuclear genetics, the Egyptian fruit bat forms a clade with the Madagascan and Comoro rousettes. The Rousettus lineage colonized Africa in a single event in the late Pliocene or early Pleistocene. Diversification into three species followed soon after, with the Egyptian fruit bat the first to branch—the Comoro and Madagascan rousettes have a more recent common ancestor with each other than with the Egyptian fruit bat.
Subspecies
There are six subspecies of Rousettus aegyptiacus.
Description
The Egyptian fruit bat is considered a medium-sized megabat. Adults have an average total body length of and an average wingspan of about . Its forearm length is and its thumb length is . Adults weigh . Males are larger than females and can be easily distinguished by their large scrotums and the prominent, stiff strands of hair around their throats. It has a dental formula of for a total of 34 teeth.