The limacoid land snail Asperitas Gude, 1911 encompasses several vividly coloured, yet poorly known species that are distributed throughout the Lesser Sunda Islands, Sulawesi, and the Moluccas. We examined the variation in shell morphology, including the use of geometric morphometrics, and reproductive anatomy of snails from Timor and several adjacent islands. These studies revealed that none of the taxa described from Timor and considered to be endemic to this island could be reliably distinguished from any of the others. In addition to the systematic ambiguity of morphological characteristics, we uncovered rather low amounts of genetic differentiation in the mitochondrial marker cytochrome c oxidase subunit I that was not consistent with the current taxonomy. Based on these observations, we conclude that there is just a single Asperitas species on Timor that exhibits notable variability in shell characters and body colour. This variability is ascribed to the combined effects of polymorphic colour patterns with locally varying selection in different habitats and along altitudinal gradients. Individuals from the adjacent islands of Flores, Sumbawa, Solor and Romang, which are deemed to represent distinct species‐level taxa, exhibit similar amounts of variation in shell and body colour. They exhibit a consistent reproductive anatomy and overall negligible amounts of mitochondrial differentiation from the populations on Timor. Patterns in shell variation do not lend support to previously held ideas that different Sunda Islands harbour distinct radiations of polytypic Asperitas species. By contrast, we suggest that the taxonomic diversity of Asperitas has been overestimated for the over‐reliance on shell features and that many presently accepted taxa are likely mere synonyms of fewer and more widespread species.

中文翻译：

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来自帝汶的教训：贝壳是 Asperitas 陆螺（柱头螺科，Dyakiidae）中较差的分类指标

1911 年的 limacoid 陆地蜗牛 Asperitas Gude 包括几种色彩鲜艳但鲜为人知的物种，它们分布在小巽他群岛、苏拉威西岛和摩鹿加群岛。我们检查了壳形态的变化，包括几何形态测量学的使用，以及来自帝汶和几个相邻岛屿的蜗牛的生殖解剖学。这些研究表明，从帝汶描述的并被认为是该岛特有的任何分类群都无法与其他分类群可靠地区分。除了形态特征的系统性模糊之外，我们还发现线粒体标记细胞色素 c 氧化酶亚基 I 中的遗传分化量相当低，这与当前的分类法不一致。基于这些观察，我们得出的结论是，帝汶只有一种 Asperitas 物种在外壳特征和体色上表现出显着的变化。这种可变性归因于多态颜色模式与不同栖息地和沿海拔梯度的局部不同选择的综合影响。来自相邻岛屿弗洛雷斯岛、松巴哇岛、索洛岛和罗曼岛的个体被认为代表了不同的物种级分类群，它们在外壳和体色方面表现出相似的变化量。他们表现出一致的生殖解剖学和总体上可忽略不计数量的来自帝汶种群的线粒体分化。贝壳变化的模式不支持先前持有的观点，即不同的巽他群岛拥有不同的多型 Asperitas 物种的辐射。相比之下，