Dataset for Ecomorphological diversification of squamates in the Cretaceous

Squamates (lizards and snakes) are highly successful modern vertebrates, with over 10,000 species. Squamates have a long history, dating back to at least 240 million years ago (Ma), and showing increasing species richness in the Late Cretaceous (84 Ma) and early Paleogene (66–55 Ma). We confirm that the major expansion of dietary functional morphology happened before these diversifications, in the mid Cretaceous, 110–90 Ma. Until that time, squamates had relatively uniform tooth types, which then diversified substantially and ecomorphospace expanded to modern levels. This coincides with the Cretaceous Terrestrial Revolution, when angiosperms began to take over terrestrial ecosystems, providing new roles for plant-eating and pollinating insects, which were in turn new sources of food for herbivorous and insectivorous squamates. There was also an early Late Cretaceous (95–90 Ma) rise in jaw size disparity, driven by the diversification of marine squamates, particularly early mosasaurs. These events established modern levels of squamate feeding ecomorphology before the major steps in species diversification, confirming decoupling of diversity and disparity. In fact, squamate feeding ecomorphospace had been partially explored in the Late Jurassic and Early Cretaceous, and jaw innovation in Late Cretaceous squamates involved expansions at the extremes of morphospace.

有鳞类（Squamates，包含蜥蜴与蛇类）是极为成功的现生脊椎动物类群，现存物种逾10000种。该类群的演化历史可追溯至至少2.4亿年前（Ma），并在晚白垩世（84 Ma）与古近纪早期（66–55 Ma）出现物种丰富度的持续提升。本研究证实，取食功能形态学的主要演化扩张发生在上述物种辐射事件之前，即白垩纪中期的110–90 Ma。在此之前，有鳞类的牙齿形态相对统一；此后其牙齿形态发生显著分化，生态形态空间也扩张至现代水平。这一演化节点与白垩纪陆地革命（Cretaceous Terrestrial Revolution）高度吻合：彼时被子植物开始主导陆地生态系统，为植食性与传粉昆虫提供了全新生态位，而这些昆虫又成为植食性与虫食性有鳞类的全新食物来源。同时在晚白垩世早期（95–90 Ma），海洋有鳞类（尤其是早期沧龙类）的辐射演化推动了颌骨尺寸形态差异度的上升。上述事件在物种大规模辐射之前就已奠定了现代有鳞类取食生态形态学的基础，证实了物种多样性与形态差异度之间的解耦现象。事实上，有鳞类的取食生态形态空间在晚侏罗世与早白垩世就已得到部分开拓；而晚白垩世有鳞类的颌骨演化创新，主要体现为形态空间极端区域的进一步扩张。