Hylaeamys megacephalus
Hylaeamys megacephalus, also known as Azara's broad-headed oryzomys or the large-headed rice rat, is a species of rodent in the genus "Hylaeamys" of family Cricetidae, of which it is the type species. It is found mainly in lowland tropical rainforest from its type locality in Paraguay north through central Brazil, French Guiana, Guyana, Suriname, and Venezuela onto Trinidad and Tobago. To its west and east, other closely related species of "Hylaeamys" are found: "H. perenensis" in western Amazonia, "H. acritus" in Bolivia, and "H. laticeps" and "H. oniscus" in the Atlantic Forest of eastern Brazil . Taxonomy. It was first described by Spanish naturalist Félix de Azara. Based on his description, several names were given to the animal, including "Mus megacephalus" Fischer, 1814 and "Mus capito" Olfers, 1818, both of which were largely forgotten for over a century. When "capito" was rediscovered in 1960, it came in use (as "Oryzomys capito") for a "species" that included about all species now placed in "Euryoryzomys", "Hylaeamys" and "Transandinomys". Later, its scope was restricted, most definitively in a detailed study in 1998 by Guy Musser and coworkers, who also reinstated the older name "Mus megacephalus" (as "Oryzomys megacephalus"). In  subsequent years, the western Amazonian "H. perenensis" was reinstated as a species and both were moved to the new genus "Hylaeamys", because they are not closely related to the type species of "Oryzomys".