Aegialomys
Encyclopedia
Aegialomys is a genus
of oryzomyine
rodent
s from the lowlands and mountains of western Peru
and Ecuador
, including the Galápagos Islands
. The species in this genus have historically been placed in Oryzomys
, but according to cladistic
research, the genus is more closely related to a group containing, among others, Nectomys
and Sigmodontomys
, than to Oryzomys. The generic name Aegialomys means "coastal mouse" in Ancient 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
, and A. galapagoensis. There is however a third, undescribed species occurring on the Ecuadorean coast and the status of the two junior synonyms of A. xanthaeolus, ica Osgood, 1944 and baroni J.A. Allen, 1897, is currently unresolved. Also, the subspecies A. galapagoensis bauri is sometimes considered a separate species.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of oryzomyine
Oryzomyini
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of family Cricetidae. It includes about 120 species in about thirty genera, distributed from the eastern United States to the southernmost parts of South America, including many offshore islands...
rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s from the lowlands and mountains of western Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
and Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, including the Galápagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
. The species in this genus have historically been placed in Oryzomys
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 of the United States and O. couesi of Mexico and Central America—are widespread; the six others have...
, but according to cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
research, the genus is more closely related to a group containing, among others, Nectomys
Nectomys
Nectomys is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is closely related to Amphinectomys and was formerly considered congeneric with Sigmodontomys...
and Sigmodontomys
Sigmodontomys
Sigmodontomys is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is related to Nectomys and Melanomys and was previously included in Nectomys. It includes two species, Sigmodontomys alfari and the much rarer Sigmodontomys aphrastus, but whether these are indeed each other's...
, than to Oryzomys. The generic name Aegialomys means "coastal mouse" in Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean 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
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, and A. galapagoensis. There is however a third, undescribed species occurring on the Ecuadorean coast and the status of the two junior synonyms of A. xanthaeolus, ica Osgood, 1944 and baroni J.A. Allen, 1897, is currently unresolved. Also, the subspecies A. galapagoensis bauri is sometimes considered a separate species.