Turtles are key components of modern vertebrate faunas and their diversity and distributions are likely to be affected by anthropogenic climate change. However, there is limited baseline data on turtle taxonomic richness through time or assessment of their past responses to global environmental change. We used the extensive Triassic– Palaeogene (252–223 Ma) fossil record of terrestrial and freshwater turtles to investigate diversity patterns, finding substantial variation in richness through time and between continents. Globally, turtle richness was low from their Triassic origin until the Late Jurassic. There is strong evidence for high richness in the earliest Cretaceous of Europe, becoming especially high following the Cretaceous Thermal Maximum and declining in all continents by the end-Cretaceous. At the K–Pg boundary, South American richness levels changed little while North American richness increased, becoming very high during the earliest Palaeogene (Danian). Informative data are lacking elsewhere for this time period. However, the Selandian–Thanetian interval, approximately 5 myr after the K–Pg mass extinction, shows low turtle richness in Asia, Europe and South America, suggesting that the occurrence of exceptional turtle richness in the post-extinction Paleocene fauna of North America is not globally representative. Richness decreased over the Eocene–Oligocene boundary in North America but increased to its greatest known level for Europe, implying very different responses to dramatic climatic shifts. Time series regressions suggest number of formations sampled and palaeotemperature are the primary influencers of facevalue richness counts, but additional factors not tested here may also be involved.

中文翻译：

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从三叠纪到古近纪追踪非海龟丰富度的模式：从起源到全球传播

海龟是现代脊椎动物群的关键组成部分，它们的多样性和分布可能会受到人为气候变化的影响。然而，通过时间或评估它们过去对全球环境变化的反应，关于海龟分类丰富度的基线数据有限。我们使用广泛的三叠纪-古近纪（252-223 Ma）陆生和淡水龟化石记录来研究多样性模式，发现丰富度随时间和大陆之间的显着变化。在全球范围内，从三叠纪起源到晚侏罗纪，海龟的丰富度一直很低。有强有力的证据表明欧洲最早的白垩纪丰富度很高，在白垩纪热最大值之后变得特别高，到白垩纪末期在所有大陆都下降。在 K-Pg 边界处，南美丰富度水平变化不大，而北美丰富度增加，在最早的古近纪（大年）变得非常高。其他地方缺乏这一时期的信息数据。然而，K-Pg 大灭绝后约 5 年的 Selandian-Thanetian 间隔显示亚洲、欧洲和南美洲的海龟丰富度较低，这表明北美洲灭绝后的古新世动物群中出现了异常丰富的海龟。不具有全球代表性。北美始新世-渐新世边界的丰富度下降，但增加到欧洲已知的最大水平，这意味着对剧烈气候变化的反应非常不同。时间序列回归表明采样的地层数量和古温度是面值丰富度计数的主要影响因素，