Climatic drivers of latitudinal variation in Late Triassic tetrapod diversity
Climatic drivers of latitudinal variation in Late Triassic tetrapod diversity
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DOI：
10.1111/pala.12514
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发表时间：
2020-11-17
期刊：
影响因子：
2.6
通讯作者：
Butler, Richard J.
中科院分区：
文献类型：
--
作者：
Dunne, Emma M.;Farnsworth, Alexander;Butler, Richard J.
纬度生物多样性梯度（LBG），即生物多样性从两极到赤道的增加，是最广泛认可的全球宏观生态格局之一，但其深时间演变及其驱动因素仍不确定。晚三叠世（237-201 Ma）是现代四足动物类群（如鳄形动物、恐龙、哺乳动物）早期演化和辐射的关键时期，与其他前新生代时期（特别是在低古纬度）相比，它在空间上得到了广泛的采样，为探索四足动物多样性的古纬度格局提供了独特的机会。本文采用采样标准化的方法，对来自古生物数据库（PBDB）的综合分布数据进行了研究，探讨了晚三叠世四足动物多样性的古纬度格局。然后利用古气候模式模拟探索了主要四足动物类群所占据的古气候范围，从而深入了解古气候对这些类群古纬度分布的影响。研究结果表明，晚三叠世四足动物总体上不符合现代型LBG；相反，采样标准化物种丰富度在中古高纬度地区最高。相反，伪鳄类动物（鳄鱼及其近亲）的丰富程度在古赤道地区是最高的，这种模式在它们随后的进化史中一直保持着。与其他四足动物类群相比，假足动物的古气候条件范围更窄，类似于现代的爬行类变温动物，而avemetarsalians（包括恐龙和翼龙的始龙类群）的古气候条件范围相对更广，更类似于现代的恒温动物，如鸟类和哺乳动物，这对恐龙的热生理进化具有重要意义。
The latitudinal biodiversity gradient (LBG), the increase in biodiversity from the poles to the equator, is one of the most widely recognized global macroecological patterns, yet its deep time evolution and drivers remain uncertain. The Late Triassic (237-201 Ma), a critical interval for the early evolution and radiation of modern tetrapod groups (e.g. crocodylomorphs, dinosaurs, mammaliamorphs), offers a unique opportunity to explore the palaeolatitudinal patterns of tetrapod diversity since it is extensively sampled spatially when compared with other pre-Cenozoic intervals, particularly at lower palaeolatitudes. Here, we explore palaeolatitudinal patterns of Late Triassic tetrapod diversity by applying sampling standardization to comprehensive occurrence data from the Paleobiology Database (PBDB). We then use palaeoclimatic model simulations to explore the palaeoclimatic ranges occupied by major tetrapod groups, allowing insight into the influence of palaeoclimate on the palaeolatitudinal distribution of these groups. Our results show that Late Triassic tetrapods generally do not conform to a modern-type LBG; instead, sampling-standardized species richness is highest at mid-palaeolatitudes. In contrast, the richness of pseudosuchians (crocodylians and their relatives) is highest at the palaeoequator, a pattern that is retained throughout their subsequent evolutionary history. Pseudosuchians generally occupied a more restricted range of palaeoclimatic conditions than other tetrapod groups, a condition analogous to modern day reptilian ectotherms, while avemetatarsalians (the archosaur group containing dinosaurs and pterosaurs) exhibit comparatively wider ranges, which is more similar to modern endotherms, such as birds and mammals, suggesting important implications for the evolution of thermal physiology in dinosaurs.