Sigmodontinae is a subfamily of rodents that includes New World rats and mice, with at least 376 species. Their distribution includes much of the New World, but the genera are predominantly South American, such as brucies. They invaded South America from Central America as part of the Great American Interchange near the end of the Miocene, about 5 million years ago. Sigmodontines proceeded to diversify explosively in the formerly isolated continent. They inhabit many of the same ecological niches that the Murinae occupy in the Old World.
The "Thomasomyini" from the Atlantic Forest of Brazil are generally thought to be not especially related to the "real" Thomasomyini from the northern Andes and the Amazon rainforest. The genera Wiedomys and Sigmodon are generally placed in their own tribe, and the "phyllotines" Irenomys, Punomys, Euneomys, and Reithrodon are considered incertae sedis.
The name "Sigmodontinae" is based on the name of the type genus, Sigmodon. This name in turn derives from the Greek roots for "S-tooth" (sigm- for "S" and odont- for "tooth", as in orthodontist) for the characteristic of the molars having an S-shape when viewed from above.
Species
The Sigmodontinae are divided into a number of tribes and genera:
Sigmodontalia
Tribe Sigmodontini
Genus †Prosigmodon
Prosigmodon chihuahuensis
Prosigmodon ferrusquiai
Prosigmodon holocuspis
Prosigmodon oroscoi
Prosigmodon tecolotum
Genus Sigmodon - cotton rats
Subgenus Sigmodon
Sigmodon hispidus species group
Allen's cotton rat, Sigmodon alleni
Arizona cotton rat, Sigmodon arizonae
Southern cotton rat, Sigmodon hirsutus
Hispid cotton rat, Sigmodon hispidus
Jaliscan cotton rat, Sigmodon mascotensis
Yellow-nosed cotton rat, Sigmodon ochrognathus
Miahuatlán cotton rat, Sigmodon planifrons
Toltec cotton rat, Sigmodon toltecus
Montane cotton rat, Sigmodon zanjonensis
Sigmodon fulviventer species group
Tawny-bellied cotton rat, Sigmodon fulviventer
Unexpected cotton rat, Sigmodon inopinatus
White-eared cotton...
