Ecology and morphology are different, and yet in comparative studies of fossil vertebrates the two are often conflated. The macroevolution of Mesozoic marine tetrapods has been explored in terms of morphological disparity, but less commonly using ecological-functional categories. Here we use ecospace modelling to quantify ecological disparity across all Mesozoic marine tetrapods. We document the explosive radiation of marine tetrapod groups in the Triassic and their rapid attainment of high ecological disparity. Late Triassic extinctions led to a marked decline in ecological disparity, and the recovery of ecospace and ecological disparity was sluggish in the Early Jurassic. High levels of ecological disparity were again achieved by the Late Jurassic and maintained during the Cretaceous, when the ecospace became saturated by the Late Cretaceous. Sauropterygians, turtles and ichthyosauromorphs were the largest contributors to ecological disparity. Throughout the Mesozoic, we find that established groups remained ecologically conservative and did not explore occupied or vacant niches. Several parts of the ecospace remained vacant for long spans of time. Newly evolved, radiating taxa almost exclusively explored unoccupied ecospace, suggesting that abiotic releases are needed to empty niches and initiate diversification. In the balance of evolutionary drivers in Mesozoic marine tetrapods, abiotic factors were key to initiating diversification events, but biotic factors dominated the subsequent generation of ecological

中文翻译：

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中生代海洋四足动物对生态空间占有的演变

生态学和形态学是不同的，但在脊椎动物化石的比较研究中，这两者经常混为一谈。中生代海洋四足动物的宏观进化已经在形态差异方面进行了探索，但很少使用生态功能类别。在这里，我们使用生态空间模型来量化所有中生代海洋四足动物的生态差异。我们记录了三叠纪海洋四足动物群的爆炸性辐射及其迅速达到高度生态差异的情况。晚三叠世灭绝导致生态差距明显缩小，早侏罗世生态空间和生态差距恢复缓慢。晚侏罗世再次实现了高水平的生态差异，并在白垩纪期间保持，当时生态空间被晚白垩世饱和。蜥翅目、海龟和鱼龙类是造成生态差异的最大因素。在整个中生代，我们发现已建立的群体在生态上保持保守，并没有探索被占用或空置的生态位。生态空间的几个部分长期空置。新进化的辐射类群几乎完全探索了无人居住的生态空间，这表明需要非生物释放来清空生态位并启动多样化。在中生代海洋四足动物进化驱动力的平衡中，非生物因素是引发多样化事件的关键，但生物因素主导了随后一代的生态系统。我们发现已建立的群体在生态上仍然保守，并没有探索被占用或空置的生态位。生态空间的几个部分长期空置。新进化的辐射类群几乎完全探索了无人居住的生态空间，这表明需要非生物释放来清空生态位并启动多样化。在中生代海洋四足动物进化驱动力的平衡中，非生物因素是引发多样化事件的关键，但生物因素主导了随后一代的生态系统。我们发现已建立的群体在生态上仍然保守，并没有探索被占用或空置的生态位。生态空间的几个部分长期空置。新进化的辐射类群几乎完全探索了无人居住的生态空间，这表明需要非生物释放来清空生态位并启动多样化。在中生代海洋四足动物进化驱动力的平衡中，非生物因素是引发多样化事件的关键，但生物因素主导了随后一代的生态系统。