Caenolestids are a group of poorly known South American marsupials with a restricted distribution in Páramo and Subpáramo environments of the Andes from Colombia and western Venezuela to Bolivia (represented by the genera Caenolestes and Lestoros), and Valdivian rainforest in southern Chile (including a separate population in Chiloé Island) and Argentina, where a single species lives: the Long-nosed shrew opossum (Rhyncholestes raphanurus). The objectives of this work were to analyze the intraspecific variability of R. raphanurus, which includes an anatomical description of the skull and dentition, describe its geographic variation, test for sexual dimorphism, and assess potential differences between continental and Island populations. Linear Mossimann-transformed variables were used to assess sexual differences within a large population (La Picada), compare sexes within other continental populations, and in a separate analysis, compare continental from Island samples. A full model Principal Components Analysis was performed to assess differences between males and females of the continental and Island populations. A thorough description of the skull and teeth of the species and comparisons with other living Caenolestidae is presented. Rhyncholestes raphanurus presents little geographic variation, even between Island and continental populations. Similarly, we found no significant difference between sexes of this species in cranial and dental measurements. We provide a detailed description of cranial morphology and its variation, and also, the first description of the occipital bones, which haven’t been previously described for any Paucituberculata. Comparative studies of continental and Chiloé Island specimens support the treatment of R. raphanurus as a single valid species, especially since morphologic and morphometric differences fall within the extremes of continental populations. The morphology of R. raphanurus clearly separates this genus from other extant Caenolestidae, and in a much greater degree than the differences found between Lestoros and Caenolestes.

中文翻译：

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Rhyncholestes raphanurus Osgood (Paucituberculata, Caenolestidae) 的变异和变异

Caenolestids 是一组鲜为人知的南美有袋动物，在从哥伦比亚和委内瑞拉西部到玻利维亚（以 Caenolestes 和 Lestoros 属为代表）的安第斯山脉的 Páramo 和 Subparamo 环境中分布有限，以及智利南部的 Valdivian 雨林（包括一个单独的种群在奇洛埃岛）和阿根廷，那里生活着一个物种：长鼻鼩鼱负鼠（Rhyncholestes raphanurus）。这项工作的目的是分析 R. raphanurus 的种内变异，其中包括头骨和牙列的解剖学描述，描述其地理变异，测试性别二态性，并评估大陆和岛屿种群之间的潜在差异。线性 Mossimann 转换变量用于评估大种群 (La Picada) 中的性别差异，比较其他大陆种群中的性别，并在单独的分析中，比较大陆样本和岛屿样本。执行完整模型主成分分析以评估大陆和岛屿种群的男性和女性之间的差异。详细描述了该物种的头骨和牙齿，并与其他现存的 Caenolestidae 进行了比较。Rhyncholestes raphanurus 几乎没有地理差异，即使在岛屿和大陆种群之间也是如此。同样，我们发现该物种的性别在颅骨和牙齿测量方面没有显着差异。我们提供了颅骨形态及其变化的详细描述，并且，枕骨的第一个描述，之前没有对任何 Paucituberculata 进行描述。大陆和奇洛埃岛标本的比较研究支持将 R. raphanurus 作为单一有效物种进行处理，特别是因为形态和形态测量差异属于大陆种群的极端情况。R. raphanurus 的形态清楚地将该属与其他现存的 Caenolestidae 区分开来，并且比 Lestoros 和 Caenolestes 之间的差异要大得多。