| 翻訳と辞書 |
Reigomys
''Reigomys primigenus'' is an extinct oryzomyine rodent known from Pleistocene deposits in Tarija Department, southeastern Bolivia. It is known from a number of isolated jaws and molars which show that its molars were almost identical to those of the living ''Lundomys''. On the other hand, the animal possesses a number of derived traits of the palate which document a closer relationship to living ''Holochilus'', the genus of South American marsh rats, and for this reason it was placed in the genus ''Holochilus'' when it was first described in 1996. The subsequent discoveries of ''Noronhomys'' and ''Carletonomys'', which may be more closely related to extant ''Holochilus'' than ''H. primigenus'' is, have cast its placement in ''Holochilus'' into doubt, and it was ultimately made the type species of a separate genus, ''Reigomys''.
==Taxonomy==
Material of ''Reigomys primigenus'' was collected in 1924 and 1927 by Elmer Riggs of the Field Museum of Natural History, but the animal was not described until 1996, when Scott Steppan formally named it as a new species of the genus ''Holochilus'' and diagnosed it, contrasting it to related species.〔Steppan, 1996, p. 523〕 The material Riggs collected includes nine mandibles, three maxillae, and five isolated molars. The specific name Steppan gave to the animal, ''primigenus'', means "primitive" in Latin and refers to the primitive features of the animal when compared to its relatives ''Holochilus'' and ''Lundomys''.〔Steppan, 1996, p. 524〕 In order to determine the relationships of his new species, Steppan carried out a cladistic analysis, in which he also included the oryzomyines ''Holochilus'', ''Lundomys'', ''Pseudoryzomys'', and ''Cerradomys'', as well as the non-oryzomyine ''Sigmodon''.〔Steppan, 1996, table 2; Weksler et al., 2006, for nomenclature〕 His results supported a close relation between ''R. primigenus'' and extant ''Holochilus'', with ''Lundomys'' and ''Pseudoryzomys'' more distantly related.〔Steppan, 1996, fig. 4A〕
In 1999, another rodent from the same group was described: ''Noronhomys'', a recently extinct species from the Brazilian island of Fernando de Noronha. Michael Carleton and Storrs Olson, who described the animal, argued that ''Holochilus primigenus'' was probably outside the clade of ''Noronhomys'' and extant ''Holochilus'' and that ''H. primigenus'' should probably be excluded from the genus.〔Carleton and Olson, 1999, p. 50〕 When Ulyses Pardiñas described another extinct rodent from this group, ''Carletonomys'' from the Pleistocene of Argentina, he suggested that ''H. primigenus'' should be placed in its own genus because of its mosaic of ''Holochilus''- and ''Lundomys''-like features.〔Pardiñas, 2008, p. 1275〕
The phylogenetic analysis conducted by Machado ''et al.'' (2014) confirmed that living members of the genus ''Holochilus'' are more closely related to ''Noronhomys'' and ''Carletonomys'' than to ''H. primigenus''. The authors moved ''H. primigenus'' to its own genus, which they named ''Reigomys''.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Reigomys」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|