关键词: 植物化石, 微细构造, Elatides, 早白垩世, 甘肃, 植物

Abstract:

As an ancient conifer, Elatides is of great significance for studying the composition of high-latitude vegetation in Northern Hemisphere during the Mesozoic Era. Some vegetative shoots and female cones of Elatides fossils with carbonaceous membrane were collected from the Lower Cretaceous, Jiuquan basin. Their gross morphology and wellpreserved features have been studied in detail. According to the features of vegetative shoots, leaf cuticular, pollen grains, female cones, cone scales and seeds, these fossils were identified as two species: Elatides harrisii Chow and Elatides curvifolia (Dunker) Nathorst. The prominent features of E. harrisii are spherical pollen grains, possessed small emulsion protrusions and smooth surface without ornamentation, being of longitudinal furrow in lateral view. The significant characteristics of E. curvifolia are their seed scale born in the base of ventral of cone scale and its tip Trifid with three ovules. These features are much similar to those of the extant Cunninghamia. It can be inferred that there may be a genetic relationship between Elatides and Cunninghamia. By researching the geological history and geographical distribution of Elatides, it is much comparable between the evolutional of the genus and the direction of the continental drift in Mesozoic, thus it can provide some paleontological evidence to the plate tectonics theory.

Key words: plant fossil, microstructure, Elatides, Early Cretaceous, Gansu Province, plants