Lundomys

Lundomys Temporal range: Late Pleistocene to Recent (Lujanian)
Lectotype partial cranium of L. molitor. The illustrated mandible represents a different species.
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Cricetidae
Subfamily:	Sigmodontinae
Genus:	Lundomys Voss & Carleton, 1993
Species:	L. molitor
Binomial name
Lundomys molitor (Winge, 1887)
Distribution of Lundomys molitor in South America. The current distribution is in red, and fossil records outside the current range are in blue.
Synonyms[2]
Hesperomys molitor Winge, 1888 Oryzomys molitor: Trouessart, 1898 Holochilus magnus Hershkovitz, 1955 Calomys molitor: Hershkovitz, 1962 Holochilus molitor: Massoia, 1980 Lundomys molitor: Voss and Carleton, 1993

Lundomys molitor, also known as Lund's amphibious rat^[3] or the greater marsh rat,^[4] is a semiaquatic rat species from southeastern South America.

Its distribution is now restricted to Uruguay and nearby Rio Grande do Sul, Brazil, but it previously ranged northward into Minas Gerais, Brazil, and southward into eastern Argentina. The Argentine form may have been distinct from the living form from Brazil and Uruguay. L. molitor is a large rodent, with the head and body length averaging 193 mm (7.6 in), characterized by a long tail, large hindfeet, and long and dense fur. It builds nests above the water, supported by reeds, and it is not currently threatened.

Its external morphology is similar to that of Holochilus brasiliensis, and over the course of its complex taxonomic history it has been confused with that species, but other features support its placement in a distinct genus, Lundomys. Within the family Cricetidae and subfamily Sigmodontinae, it is a member of a group of specialized oryzomyine rodents that also includes Holochilus, Noronhomys, Carletonomys, and Pseudoryzomys.