A large sample (>100 specimens) of the fossil rodent Thisbemys Wood, 1959, from the early Eocene (late Bridgerian; Br3) Washakie Formation of Wyoming is described. Two species are recognized: a new species, T. intermedius n. sp., and Thisbemys cf. T. uintensis (Osborn, 1895). The large sample size of the former has allowed for a detailed study of variation in size and morphology within the species based on tooth-wear. As a result, some systematic changes in the species included in this genus are suggested: (1) T. brevicrista Ostrander, 1986, is limited to the holotype, and all specimens previously referred to T. brevicrista are likely referable to T. plicatus Wood, 1962; (2) statistical analysis supports the separation of T. plicatus from T. corrugatus Wood, 1959, based on its smaller size and less-crenulated cheek teeth, which corroborates their existence at different horizons (T. plicatus earlier Bridgerian [Br2], T. corrugatus late Bridgerian [Br3]); (3) Paramys delicatior Leidy, 1871, is suggested as the senior synonym of T. plicatus Wood, 1962; (4) T. perditus Wood, 1962, is limited to the early Eocene (Washatchian: Wa1-6); and (5) all specimens previously referred to T. nini Wood, 1962, except the holotype, are referred to T. perditus (fide Korth, 1984; contra Anderson, 2015).UUID: http://zoobank.org/59c101e2-cd55-4dce-aeea-3da48c4fbd53

中文翻译：

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来自怀俄明州沃什基组（始新世早期，布里奇利安晚期）的始新世 ischyromyid 啮齿动物 Thisbemys 对该属的系统学进行了评论

啮齿动物化石的大样本（>100 个样本）这贝米斯伍德，1959 年，描述了怀俄明州早始新世（布里奇利安晚期；Br3）Washakie 组。两个物种被识别：一个新物种，吨.中间体n. sp.，和这贝米斯参看。吨.滇滇（奥斯本，1895 年）。前者的大样本量允许详细研究基于牙齿磨损的物种内大小和形态的变化。因此，建议该属的物种发生一些系统性变化：（1）吨.布雷维克里斯塔Ostrander, 1986, 仅限于正模标本，之前提到的所有标本吨.布雷维克里斯塔可能参考吨.褶裥伍德，1962；(2) 统计分析支持分离吨.褶裥从吨.波纹Wood，1959，基于其较小的尺寸和较少的龅牙，这证实了它们在不同的视野中的存在（吨.褶裥早期的布里奇里安 [Br2]，吨.波纹晚期布里奇里安 [Br3]); (3)熟食蟹Leidy, 1871, 被建议作为高级同义词吨.褶裥伍德，1962；(4)吨.不幸的Wood，1962，仅限于始新世早期（Washatchian：Wa1-6）；(5) 所有先前提及的样本吨.妮妮Wood，1962 年，除了正模标本外，都提到了吨.不幸的（Fide Korth，1984 年；反对安德森，2015 年）。UUID：http://zoobank.org/59c101e2-cd55-4dce-aeea-3da48c4fbd53