Data from: Cenozoic dynamics of shallow-marine biodiversity in the Western Pacific

Aim: Cenozoic dynamics of large-scale species diversity patterns remain poorly understood, especially for the Western Pacific, in part, because of the paucity of well-dated fossil records from the tropics. This article aims to reveal the spatiotemporal dynamics of species diversity in the Western Pacific through the Cenozoic, focusing on the tropical Indo-Australian Archipelago (IAA) biodiversity hotspot.
Location: Tropical and north-western Pacific Ocean.
Methods: We analysed well-preserved fossil ostracodes from the tropical Western Pacific and combined their diversity data with other published data from the region to reconstruct Cenozoic dynamics of species diversity in the tropical and north-western Pacific Ocean. We fitted generalized additive models to test for differences in richness over time and across geographical regions while accounting for sample-size variation among samples.
Results: Low-, mid- and high-latitude regions all show a similar diversity trajectory: diversity is low in the Eocene and Oligocene, increases from the Early Miocene to the Plio-Pleistocene but then declines to the present day. Present-day high biodiversity in these regions was established during the Pliocene with a remarkable diversity increase at that time. Latitudinal diversity patterns are relatively flat and never show a simple decline from the tropics to higher latitudes.
Main conclusions: Western Pacific Cenozoic ostracodes exhibit a spatiotemporal pattern of species diversity that is inconsistent with the commonly reported and persistent pattern of declining diversity from the tropics to the extratropics. While this inconsistency could be interpreted as evidence that ostracodes are a contrarian clade, Atlantic ostracodes display a standard latitudinal species diversity gradient. Contrasting patterns between oceans suggest an important role for regional factors (e.g. plate tectonics and temporal geomorphological dynamics) in shaping the biodiversity of the Western Pacific.

研究背景：新生代大尺度物种多样性格局的动态机制仍有待深入解析，西太平洋区域的相关研究尤为匮乏，部分原因在于热带地区缺乏定年精准的化石记录。本文旨在聚焦热带印度-澳大利亚群岛（Indo-Australian Archipelago, IAA）这一生物多样性热点区域，揭示西太平洋新生代物种多样性的时空动态变化。
研究区域：热带及西北太平洋海域。
研究方法：本研究分析了热带西太平洋海域保存完好的介形类化石，将其多样性数据与该区域已发表的相关数据相结合，以此重建热带及西北太平洋海域新生代的物种多样性格局动态。我们采用广义加性模型，在考量样本间采样量差异的前提下，检验不同地质时期及不同地理区域的物种丰富度差异。
研究结果：低纬度、中纬度与高纬度区域均呈现出相似的多样性格局演化轨迹：始新世至渐新世时期多样性水平较低，自早中新世至上新世-更新世阶段多样性逐步上升，随后直至现代出现下降。上述区域现今的高生物多样性水平形成于上新世，该时期存在显著的多样性增长事件。纬度多样性格局相对平缓，从未呈现出从热带向高纬度地区单调递减的经典模式。
主要结论：西太平洋新生代介形类的物种多样性格局，与学界普遍报道的、从热带向非热带区域持续递减的经典纬度多样性格局并不一致。尽管这一差异或许可被解读为介形类类群存在独特演化模式，但大西洋介形类却呈现出标准的纬度多样性格局。两大洋之间的格局差异表明，区域因素（如板块构造与地貌动态演化）在塑造西太平洋生物多样性的过程中发挥了重要作用。