Abstract

Here we report a pollen organ from the upper Permian of the Dead Sea region with in situ pollen showing a wall structure typical for lyginopterid seed ferns. The single specimen resembles the dispersed seed-fern pollen organs Dictyothalamus and Melissiotheca in being composed of numerous densely positioned, radiating pollen sacs that together form a characteristic honeycomb-like surface pattern. The small, rounded to oval, non-saccate cryptaperturate in situ pollen grains have a verrucate sculpture and show an alveolate wall ultrastructure with alveoli arranged in several tiers. The lyginopterids, a group of seed ferns, first appeared in the latest Devonian and were very widespread across Euramerica during the Mississippian. The group shows a clear demise in the middle and late Pennsylvanian. The youngest representatives have been reported from late Permian peat-swamps in Cathaysia. The morphology of the pollen organ, the ultrastructure of the pollen, and associated foliage present further evidence that lyginopterid seed ferns persisted until the late Permian and demonstrate that they were not restricted to peat-forming swamp environments, but that they were able to survive in drier environments.

抽象的

在这里，我们报告了来自死海地区上二叠纪的花粉器官，其原位花粉显示了鳞翅目种子蕨类植物的典型壁结构。单个标本类似于散布的种子蕨类花粉器官D齿草和梅利西奥卡，由许多密集放置的放射状花粉囊组成，共同形成特征性的蜂窝状表面图案。小的，圆的，椭圆形的，不精确的原位穿孔花粉粒具有精确的雕刻，并显示出肺泡壁超微结构，其中肺泡排列成几层。lyginopterids是一组种子蕨类植物，最早出现在最新的泥盆纪时期，在密西西比时期广泛分布于整个美洲。该小组在宾夕法尼亚州的中后期显示出明显的消亡。据报道，最年轻的代表来自华夏的二叠纪晚期泥炭沼泽。花粉器官的形态，花粉的超微结构以及相关的叶子进一步证明了鳞翅目蕨类植物的蕨类植物一直持续到二叠纪晚期，并证明它们并不局限于泥炭形成的沼泽环境，而是能够在泥炭环境中生存。较干燥的环境。