Data from: Why is Madagascar special? The extraordinarily slow evolution of pelican spiders (Araneae, Archaeidae)

Although Madagascar is an ancient fragment of Gondwana, the majority of taxa studied thus far appear to have reached the island through dispersal from Cenozoic times. Ancient lineages may have experienced a different history compared to more recent Cenozoic arrivals, as such lineages would have encountered geoclimatic shifts over an extended time period. The motivation for this study was to unravel the signature of diversification in an ancient lineage by comparing an area known for major geoclimatic upheavals (Madagascar) versus other areas where the environment has been relatively stable. Archaeid spiders are an ancient paleoendemic group with unusual predatory behaviors and spectacular trophic morphology that likely have been on Madagascar since its isolation. We examined disparities between Madagascan archaeids and their non-Madagascan relatives regarding timing of divergence, rates of trait evolution, and distribution patterns. Results reveal an increased rate of adaptive trait diversification in Madagascan archaeids. Furthermore, geoclimatic events in Madagascar over long periods of time may have facilitated high species richness due to montane refugia and stability, rainforest refugia, and also ecogeographic shifts, allowing for the accumulation of adaptive traits. This research suggests that time alone, coupled with more ancient geoclimatic events allowed for the different patterns in Madagascar.尽管马达加斯加是冈瓦纳古陆（Gondwana）的古老残块，但迄今已研究的多数分类群（taxa）似乎均通过新生代（Cenozoic）时期以来的扩散途径抵达该岛屿。古老演化支相较于新生代后期迁入的类群，可能经历了截然不同的演化历史——这类古老支系在更长的时间跨度内曾遭遇持续的地质气候变迁。本研究的初衷是，通过对比以剧烈地质气候动荡著称的区域（马达加斯加）与环境相对稳定的其他区域，解析某一古老演化支的多样化特征。古蛛科（Archaeidae）蜘蛛是一类古老的古特有类群，具备独特的捕食行为与极具辨识度的营养形态，大概率自马达加斯加脱离冈瓦纳古陆以来便栖息于此。本研究对比了马达加斯加古蛛与其非马达加斯加近缘类群在分化时间、性状演化速率及分布格局上的差异。研究结果显示，马达加斯加古蛛的适应性性状多样化速率显著提升。此外，马达加斯加长期存在的地质气候事件——包括山地避难所与生境稳定性、雨林避难所的留存，以及生态地理变迁——或许推动了高物种丰富度的形成，并为适应性性状的积累创造了条件。本研究表明，仅以漫长的时间跨度结合更古老的地质气候事件，便造就了马达加斯加地区独特的演化模式。