We report on the colonization and diversification of linyphiid spiders in the Pacific oceanic archipelago of Juan Fernandez. About 50 spider species occur naturally in these islands, most of them endemic and about half of them are linyphiids. Linyphiidae includes no fewer than 15 species of Laminacauda and three of Neomaso (with several additional undescribed species in the latter genus), all of them single island endemics. There are three additional linyphiid endemic genera, two monotypic and one, Juanfernandezia, with two species. Unlike the rather uniform somatic morphology and small ground sheet webs of the continental Laminacauda and Neomaso species, the Juan Fernandez endemics exhibit morphological features and life history traits that are very rare or unknown in any other linyphiids. A multi-locus phylogenetic analysis confirms at least five independent Juan Fernandez colonizations of Linyphiidae, two within the same genus, and three of which underwent subsequent local diversification. Different calibrations suggest alternative colonization timelines, some at odds with island ages, but all agree on similar diversification timings of the endemic lineages. Rare phenotypic traits (e.g. gigantism, massive chelicerae or elongated legs) evolved multiple times independently within the islands. Based on the remarkable levels of eco-phenotypic differentiation in locally diversified species showing densely packed distributions, we propose that Laminacauda, and probably Neomaso, constitute a case of adaptive radiation.

中文翻译：

---

胡安·费尔南德斯南太平洋群岛织布蜘蛛 (Linyphiidae) 的重复定殖、适应性辐射和趋同进化

我们报告了胡安·费尔南德斯太平洋群岛中线虫蜘蛛的定殖和多样化。大约 50 种蜘蛛物种在这些岛屿上自然生长，其中大部分是地方性的，其中大约一半是线虫。Linyphiidae 包括不少于 15 种Laminacauda和 3 种Neomaso（后一属还有几个未描述的物种），它们都是单岛特有的。有另外三个 linyphiid 地方性属，两个单型属和一个Juanfernandezia属，有两个种。与大陆Laminacauda和Neomaso相当均匀的体细胞形态和小型地表网不同物种，胡安费尔南德斯地方病表现出形态特征和生活史特征，在任何其他线虫科动物中都非常罕见或未知。多位点系统发育分析证实了至少五个独立的胡安·费尔南德斯 (Juan Fernandez) 定殖的 Linyphiidae，两个在同一属内，其中三个经历了随后的局部多样化。不同的校准表明了替代的殖民时间表，有些与岛屿年龄不一致，但都同意地方性谱系的相似多样化时间。罕见的表型特征（例如巨人症、巨大的螯肢或拉长的腿）在岛屿内独立进化了多次。基于显示密集分布的局部多样化物种的显着水平的生态表型分化，我们提出Laminacuda，可能还有 Neomaso，构成了适应性辐射的一个案例。