Data from: The modulating role of traits on the biogeographic dynamics of chondrichthyans from the Neogene to the present

The environmental transformations that occurred during the Neogene had profound effects on spatio-temporal biodiversity patterns, yet the modulating role of traits (i.e. physiological, ecological and life history traits) remains little understood. We tested this idea using the Neogene fossil record of chondrichthyans along the temperate Pacific coast of South America (TPSA). Information of georeferenced occurrences and ecological and life history information of 38 chondrichthyan fossil genera in 42 Neogene sites was collected. Global georeferenced records were used to estimate present-day biogeographic distributions of the genera and to characterize the range of oceanographic conditions in which each genus lives as a proxy of their realized niche. Biogeographic range shifts (Neogene - present) were evaluated at regional and local scales. The role of traits as drivers of different range dynamics was evaluated using random forest models. The magnitude and direction of biogeographic range shifts were different at both spatial scales. At a regional scale, 34% of genera contracted their ranges, disappearing from the TPSA. At a local scale, a similar proportion of genera expanded and contracted their southern endpoints of distribution. The models showed a high precision at both spatial scales of analyses, but the relative importance of predictor variables were different. At a regional scale, disappearing genera tended to have a higher tolerance to salinity, lower sea surface temperature (SST) range, and smaller body sizes. At a local scale, genera contracting their ranges tended to live at greater depths, tolerate lower levels of primary productivity, and show a reduced tolerance to higher and lower SST ranges. The magnitude and direction of the changes in the range distribution were scale-dependent and variable across the genera. Hence, the multiple environmental exogenous factors interacted with taxon traits during the Neogene, creating a mosaic of biogeographic dynamics.

新近纪（Neogene）期间发生的环境变迁对生物多样性的时空格局产生了深远影响，但生物性状（即生理、生态与生活史性状）的调节作用仍鲜为人知。本研究以南美温带太平洋沿岸（temperate Pacific coast of South America，以下简称TPSA）的软骨鱼纲（chondrichthyans）新近纪化石记录为研究对象，对该假说进行验证。我们收集了42个新近纪遗址中38个软骨鱼化石属的地理参考产出数据，以及其生态与生活史相关信息。本研究利用全球地理参考记录，估算了各属当前的生物地理分布范围，并以各属现生栖息的海洋环境条件范围作为其实际生态位（realized niche）的替代指标。随后在区域与局域尺度上，评估了生物地理分布范围的变化（新近纪-现代）。通过随机森林模型（random forest models），我们分析了性状作为不同分布动态驱动因子的作用。研究结果表明，生物地理分布范围变化的幅度与方向在两类空间尺度上存在显著差异：在区域尺度上，34%的属出现了分布范围收缩，并从TPSA消失；在局域尺度上，分布范围扩张与收缩的属占比相近，且变化均体现为分布南界的调整。模型在两类空间尺度的分析中均表现出较高的预测精度，但预测变量的相对重要性存在差异。区域尺度上，消失的属往往对盐度具有更高的耐受性，海表温度（sea surface temperature，以下简称SST）范围更窄，且体型更小。局域尺度上，分布范围收缩的属多栖息于更深水域，对初级生产力的耐受水平更低，同时对SST过高与过低的耐受范围均有所缩减。综上，分布范围变化的幅度与方向具有尺度依赖性，且随类群而异。由此可见，新近纪时期多种外源环境因子与类群性状相互作用，共同塑造了多样的生物地理动态格局。