Oryzomys is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which are widespread; the six others have more restricted distributions. The name was established in 1857 by Spencer Fullerton Baird for the marsh rice rat and was soon applied to over a hundred species.
About Oryzomys in brief
Oryzomys is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which are widespread; the six others have more restricted distributions. The name was established in 1857 by Spencer Fullerton Baird for the marsh rice rat and was soon applied to over a hundred species of American rodents. Two, maybe three, species have gone extinct over the last two centuries and at least one other is endangered, but the widespread marsh Rice rat and O. couesi are not threatened. Species are medium-sized rats with long, coarse fur. The habitat includes various kinds of wetlands, such as lakes, marshes, and rivers. The animals have broad feet with reduced or absent ungual tufts of hair around the claws and, in at least some species, with webbing between the toes. After a gestation period of 21 to 28 days, about four young are born. Species of OryZomys are infected by numerous parasites and carry at least three hantaviruses, one of which also infects humans. It is one of several tribes within the subfamily Sigmodontinae of the family Cricetidae, which includes hundreds of other species of mainly small rodents, distributed mainly in the Americas and Eurasia. It was first described by Richard Harlan, who first described it as a subgenus of the now-defunct Mammalus Hesperus in 1874.
In 1898, Édouard Trouard ascribed it to the genus Hesperomys, which was raised to generic rank in subsequent years and numerous additional species were ascribed to it, many of which were moved to separate genera. In 1890, Ory Zomys was elevated to the rank of genera, and in 1995 it was raised again to generic Ory zomys. In 2006, ten new genera were established for species previously placed in Oryazomys; additional species may be recognized in the future. The genus is most closely related to a group including Holochilus, Lundomys and PseudoryzomYS, and may thus be examples of convergent evolution. It has 56chromosomes, lack a gall bladder, and have a complex penis with some traits that are rare among oryzomyines; these characteristics are unknown in the other species in this genus. The rostrum is broad and the braincase is high. The first three are adaptations to the semiaqatic lifestyle that Oryzyms and the members of the Holochilus group share. The name Oryyzyms refers to the feeding habits of the marshrice rat of the eastern U.S. and mysarus, which combines the Greek oryza \”mouse\” and myyza and mysus. It had been described by Richard Harlan twenty years earlier.
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This page is based on the article Oryzomys published in Wikipedia (as of Dec. 01, 2020) and was automatically summarized using artificial intelligence.
