Abstract

A new species of the cricetid rodent genus Thomasomys is described from the montane forests of the Cordilleras del Cóndor and Kutukú, southeastern Ecuador, at elevations between 1,770 and 2,215 m. The species has a large body size (head and body length 137–147 mm) in comparison with other species in the genus, and also is distinguished from its congeners by presenting a tail longer than the head–body length, presence of genal vibrissae 1 and 2, wide presphenoid, first and second lower molars with ectolophid, and third lower molar slightly shorter than the second. A molecular phylogeny based on mitochondrial genes resolved the new species a member of the “aureus” group, most closely related to Thomasomys aureus sensu stricto (genetic distance 8.57%) and as well as an additional undescribed species from southeastern Ecuador. This finding increases the diversity of Thomasomys to 46 species, of which 17 species are present in Ecuador. In addition, the species described herein is the first Thomasomys from the Amazonian basin, a genus that up to now was thought to be restricted to Andean ranges.

中文翻译：

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发现第一批亚马逊Thomasomys（啮齿目、仓鼠科、Sigmodontinae）：来自厄瓜多尔偏远的Cordilleras del Cóndor 和Kutukú 的新物种

摘要

在厄瓜多尔东南部的科迪勒拉斯德尔康多尔和库图库的山地森林中，描述了一种新的仓鼠属啮齿动物属Thomasomys，海拔在 1,770 至 2,215 米之间。与该属中的其他物种相比，该物种具有较大的体型（头部和身体长度为 137-147 毫米），并且与同类物种的区别在于尾巴长于头身长度，存在触须 1 2、蝶前骨宽，第一、第二下磨牙有外齿，第三下磨牙略短于第二磨牙。基于线粒体基因分子系统发育解决了新品种的“金黄色葡萄球菌”组的成员，最密切相关的南美岭鼠属金黄色葡萄球菌sensu stricto (遗传距离 8.57%) 以及来自厄瓜多尔东南部的其他未描述物种。这一发现将Thomasomys的多样性增加到46 种，其中 17 种存在于厄瓜多尔。此外，本文描述的物种是亚马逊河流域的第一个Thomasomys，该属迄今为止被认为仅限于安第斯山脉。