Adaptive radiation of the comatulid crinoids
Adaptive radiation of the comatulid crinoids
复制标题
海百合的适应性辐射
作者：
D. L. Meyer;D. Macurda
现代海百合主要是comatulids（无柄形式），范围从潮间带到深海深处。现代有柄海百合仅限于深度超过100米。在过去的地质时期，一些海百合生活在几十米或更深的珊瑚礁和海岸环境中。后三叠纪辐射的comatulids假设的主要车辆是缺乏永久固定的底层和移动的能力。复杂的肌肉关节的发展使爬行或游泳成为可能，这有助于栖息地的选择和避免压力和捕食者。这些和其他适应可能赋予了comatulids在浅水环境中的生存能力比跟踪海百合更高。现代有柄海百合缺乏在comatulids中看到的移动性和复杂的行为适应。可能的是，浅水中的海百合无法科普中生代晚期大量食肉硬骨鱼的辐射，并被限制在更深的深度，而适应性更强的comatulids在浅水中获得了优势。
Modern crinoids are dominated by the comatulids (unstalked forms) which range from the intertidal to abyssal depths. Modern stalked crinoids are restricted to depths greater than about 100 m. In the geologic past some stalked crinoids lived at depths of a few tens of meters or less in reef and bank environments. The primary vehicles postulated for the post-Triassic radiation of comatulids are lack of permanent fixation to the substratum and the capacity for mobility. Development of complex muscular articulations has enabled crawling or swimming which serve in habitat selection and avoidance of stress and predators. These and other adaptations may have bestowed on comatulids a higher survival capacity in shallow-water environments compared to stalked crinoids. Modern stalked crinoids lack mobility and complex behavioral adaptations seen in comatulids. Possibly, stalked crinoids in shallow water were unable to cope with the radiation of abundant, predaceous bony fishes in the late Mesozoic and became restricted to greater depths while the more adaptable comatulids gained ascendancy in shallow water.