Notiomys

Notiomys is a genus of South American rodents in the family Cricetidae. The genus was described in 1954 by George Gaylord Simpson and is comprised of two living species. These species are native to the Andes Mountains. Notiomys is characterized by its relatively small size, long tail, and specialized adaptations for a semi-aquatic lifestyle. Their fur is dense and water-repellent, aiding them in their environment.

The two recognized species within the genus are Notiomys edwardsi and Notiomys thomasi. Notiomys edwardsi is found in the high-altitude regions of Peru and Bolivia. Notiomys thomasi is distributed in the Andean foothills of Ecuador and Peru. Both species inhabit riparian habitats, typically living in burrows along the banks of streams and rivers. Their diet consists mainly of aquatic vegetation, insects, and small invertebrates.

The phylogenetic relationships of Notiomys within Cricetidae are still under investigation, but they are generally placed within the subfamily Sigmodontinae, which includes many other South American rodents. Information on the reproductive biology and social behavior of Notiomys is limited due to their elusive nature and challenging habitat. Conservation status varies between the species, with some populations facing threats from habitat degradation and agricultural expansion. Further research is needed to fully understand the ecology and evolutionary history of this genus.