ABSTRACT The genus Neacomys includes 10 recognized species of Neotropical spiny mice in the tribe Oryzomyini. Five species have previously been reported from Peru, but the small-bodied Peruvian taxa remain unrevised. In this report, we present the first systematic and taxonomic revision of small-bodied Neacomys populations in Peru and describe two new species based on molecular, morphological, and karyotype data: (1) Neacomys rosalindae, sp. nov., from northeastern Peru, is distinguished from congeneric species by, among other differences, short incisive foramina with a wide maxillary portion of the septum, a small subsquamosal fenestra, and a karyotype of 2n = 48, FN = 50. (2) Neacomys macedoruizi, sp. nov., from central Peru, is distinguished by its gray-based ventral fur, large infraorbital foramen, and karyotype of 2n = 28, FN = 36, with a distinctively large pair of metacentric chromosomes. The results of our molecular analyses suggest that N. minutus (as currently recognized) is a species complex comprised of N. minutus sensu stricto, N. macedoruizi, and a third form that remains to be described. The other species described here, N. rosalindae, is the sister taxon to a cluster that includes the N. minutus complex plus N. musseri. Our data suggest that the upper Amazon River constitutes an important dispersal barrier for species in this genus.

中文翻译：

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秘鲁小体鼠科（啮齿目：仓鼠科）系统学介绍及两个新物种的描述

摘要 Neacomys 属包括 Oryzomyini 部落中 10 种公认的新热带多刺小鼠。秘鲁以前曾报道过五种物种，但秘鲁的小型分类群仍未修改。在本报告中，我们介绍了秘鲁小体型 Neacomys 种群的首次系统和分类学修订，并根据分子、形态和核型数据描述了两个新物种：(1) Neacomys rosalindae，sp。nov.，来自秘鲁东北部，与同类物种的区别在于，除其他差异外，短切牙小孔，中隔的上颌骨部分较宽，鳞状下孔小，核型为 2n = 48，FN = 50。 (2) Neacomys macedoruizi, sp. nov.，来自秘鲁中部，以灰色为主的腹侧毛皮、大眶下孔和核型为 2n = 28、FN = 36、具有一对特别大的中性着丝染色体。我们的分子分析结果表明，细小猪笼草（目前公认的）是一种由狭小猪笼草、马塞多瑞兹猪笼草和有待描述的第三种形式组成的物种复合体。此处描述的其他物种罗莎林猪笼草是包含 N. minutus 复合体和 N. musseri 的集群的姊妹分类群。我们的数据表明，亚马逊河上游构成了该属物种的重要传播障碍。是包含 N. minutus complex 和 N. musseri 的集群的姐妹分类群。我们的数据表明，亚马逊河上游构成了该属物种的重要传播障碍。是包含 N. minutus complex 和 N. musseri 的集群的姐妹分类群。我们的数据表明，亚马逊河上游构成了该属物种的重要传播障碍。