''Aegialomys'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of oryzomyine

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s from the lowlands and mountains of western

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

, including the

Galápagos Islands The Galápagos Islands () are an archipelago of volcanic islands in the Eastern Pacific, located around the equator, west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of sli ...

. The species in this genus have historically been placed in ''

Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and ...

'', but according to

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

research, the genus is more closely related to a group containing, among others, ''

Nectomys ''Nectomys'' is a genus of rodent in the tribe Oryzomyini of family Cricetidae. Musser and Carleton, 2005. It is closely related to '' Amphinectomys'' and was formerly considered congeneric with '' Sigmodontomys''. It consists of five species, wh ...

'' and ''

Sigmodontomys ''Sigmodontomys'' is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is related to ''Nectomys ''Nectomys'' is a genus of rodent in the tribe Oryzomyini of family Cricetidae. Musser and Carleton, 2005. It is closely related t ...

'', than to ''Oryzomys''. The generic name ''Aegialomys'' means "coastal mouse" in

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

( "coast" and "mouse") and references the mostly coastal occurrence of the genus. ''Aegialomys'' species have a greyish to buff dorsal pelage which is divided sharply from the white to light yellow ventral pelage. They have relatively short ears. There are crowns of hair at the bases of the toes. The tail is equal to or longer than the body and is darker above than below. There are two commonly recognized and described species in the genus: the mainland '' A. xanthaeolus'', the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, and '' A. galapagoensis''. There is however a third, undescribed species occurring on the Ecuadorian coast and the status of the two possible junior synonyms of ''A. xanthaeolus'', ''A. ica'' Osgood, 1944 and ''A. baroni'' J.A. Allen, 1897, is currently unresolved, although they have been described as distinct species, as has the subspecies ''A. galapagoensis bauri''.

References

* Rodent genera Taxa named by Marcelo Weksler Taxa named by Alexandre Reis Percequillo {{Sigmodontinae-stub