Sigmodontinae

Sigmodontinae is a subfamily of rodents that includes New World rats and mice. It has at least 376 species, and when some other groups are included, the total rises to at least 508. These animals are found mostly in South America, but they live across much of the New World.

These rodents arrived in South America from Central America near the end of the Miocene, about 5 million years ago, during an event called the Great American Interchange. After arriving, they quickly diversified and filled many different environments, similar to how Murinae live in the Old World.

The name Sigmodontinae comes from the type genus Sigmodon. This name is based on Greek words meaning "S-tooth" because the molars of these animals have an S-shape when viewed from above. Different groups within Sigmodontinae, like the Wiedomys and Sigmodon genera, have their own unique traits and relationships.

Species

Further information: List of sigmodontines

The Sigmodontinae are a group of rodents that includes many types of New World rats and mice. There are at least 376 known species. Some scientists group certain other rodents with them, which brings the total number of species to at least 508.

The Sigmodontinae are organized into several groups called tribes and genera, which include many different species of rats and mice adapted to various environments. Some notable groups are:

• Sigmodontalia: This group includes cotton rats and fish- and crab-eating rats, among others.
• Oryzomyalia: This group includes rice rats, marsh rats, and several other types of rodents.

These rodents are found in many parts of South and Central America, living in diverse habitats from forests to grasslands.