Abstract

Akodon is the second most diverse genus of sigmodontine rodents, comprising 40 extant species. Widely distributed through different environments of South America, the genus ranges from forested to open-vegetation areas, from semiarid to mesic regions, and from Andean altitudes to the lowlands of eastern Brazil. In Brazil, most species are from the Atlantic Forest, inhabiting lowland and montane habitats, with a few taxa also present in areas transitional with the Cerrado and Pantanal. Based on an integrative approach of genetics (cytogenetic and molecular data) and morphology (qualitative and quantitative external and craniodental data), we present in this contribution the hypothesis of a new species of Akodon based on specimens collected in the southwestern limit of the Cerrado domain, in the seasonally dry forests of the Serra da Bodoquena, Mato Grosso do Sul, Brazil. The new species was recovered as a distinct lineage sister to Akodon philipmyersi, a poorly known species from the Northern Campos grasslands of Misiones Province, Argentina, and can be distinguished from its congeners by its karyotype (2n = 40, FN = 40), morphology (morphometric, pelage, and skull characters), as well as by its degree of genetic divergence (above 7.5% in Cytb sequences). This new species is endemic to the Cerrado, one of the world’s biodiversity hotspots, and to Serra da Bodoquena, one of the top priority areas for conservation in Brazil. Moreover, the new species increases the number of lineages of Akodon in Brazil, emphasizing the richness and endemism currently found in the Cerrado domain, and the importance of the open formations to the diversification of Neotropical taxa.

中文翻译：

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巴西C虫科特有种的Akodon Meyen，1833年（啮齿类：Cricetidae：Sigmodontinae）特有种

摘要

Akodon是Sigmodontine啮齿动物的第二大多样性物种，包含40种现存物种。该属广泛分布于南美的不同环境中，范围从森林到开阔的植被区域，从半干旱到麦地那地区，从安第斯山脉的高度到巴西东部的低地。在巴西，大多数物种都来自大西洋森林，栖息在低地和山地生境中，在塞拉多和潘塔纳尔河过渡带的地区也有一些分类群。基于遗传学（细胞遗传学和分子数据）和形态学（定性和定量外部和颅齿数据）的综合方法，我们在此贡献中提出了新的Akodon物种的假设根据在塞拉多地区西南边界采集的标本，该标本位于巴西南马托格罗索州塞拉达博多奎纳的季节性干旱森林中。该新物种是作为Akodon philipmyersi的独特世系姐妹而发现的，Akodon philipmyersi是来自阿根廷米西奥内斯省北部Campos草原的一个鲜为人知的物种，可以通过其核型（2n = 40，FN = 40），形态学与同类动物区分开来。 （形态学，骨质和头骨特征）以及其遗传差异程度（在Cytb序列中超过7.5％）。这种新物种是世界上生物多样性热点地区之一的塞拉多（Cerrado）和巴西最重要的保护区之一塞拉达博多奎纳（Serra da Bodoquena）的特有物种。而且，新物种增加了巴西的Akodon，强调了目前在塞拉多地区发现的丰富性和地方性，以及开放形式对新热带分类群多样化的重要性。