掌鳞刺属演化及晚泥盆世环境变迁

牙形石掌鳞刺属Palmatolepis齿台结构和形态随时间演替 ,由近正三角形向长三角形、长菱形演化 ,在F/F界线附近受地质事件的影响而中断 ,使Palmatolepis齿台结构呈二段式发展 ,在Palmatolepis的分子中 ,那些演化速度快 ,结构变化大的分子首先灭绝 ,而那些演化速度慢 ,结构变化小的分子延续时间长 ,分布范围也更加广泛 ,在地质事件中被保留下来并得以延续 ,这种演化规律可能是生物有选择性灭绝与复苏的原因之一。晚泥盆世F/F之交环境的变化可能是由于海退 ,海底毒气喷发 ,超量金属元素的污染造成的

TEXTURAL EVOLUTION OF PALMATOLEPIS AND ENVIRONMENTAL CHANGE IN LATE DEVONIAN

Change in platform's shapes and texture of conodont Palmatolepis genus had been found by study, their shapes changed from regular triangle to long triangle and rhombus. But, the change had been interrupted by the geological event of F/F in Devonian and the development of Palmatolepis appeared two periods in shapes. These species that their shapes and textures developed quickly were first extinction, and those species that their shapes and textures changed slowly might continuously lived and developed during geological events. It is one of cause that bio-extinction was selective during geological events. Through study, the regression, the eruption of poison gas at seafloor, extra-metal element polluted water is the causes of environmental change in late Devonian.