假希瓦格■类生物生活方式探讨

A DISCUSSION ON THE LIFE STYLE OF PSEUDOSCHWAGERINA(FUSULINID)

假希瓦格■为生活在早二叠世浅海环境中的■类生物,一般认为该时期■类生物的生活方式为底栖。由于假希瓦格■的形态与生活在同时期的其它■类存在较大的差异,它们的生活方式是否相同?为探讨这一问题,本文选取了中国华南地区的假希瓦格■8种9个样本进行了统计分析,统计了假希瓦格■9个样本的壳圈数、长轴、短轴及每一壳圈的长轴、短轴和壳壁厚度,利用这些参数计算得到了■的重力、海水中■所受的浮力,结合海洋中水流的运动方式,分析了上升海流对9个样本影响,结果表明,轴率越小的■越容易受上升海流的影响,从而改变其生活方式,结合假希瓦格■的生活环境,初步认为假希瓦格■的生活方式为水动力条件较弱时,其以底栖生活为主,当水动力条件较强时,其生活方式可能由底栖变为漂浮。

Pseudoschwagerina is a genus of fusulinid which lived in Late Carboniferous to Middle Permian.It is gene-rally believed that the life style of fusulinids is benthic.Since the shape of Pseudoschwagerina is different from the other fusulinids lived in the same period,their life styles are identical or not？ In order to solve this problem,we selected 9 samples from 8 species of Pseudoschwagerina in South China,counted the shell turns and measured axis specimen,and thickness of the shell and axis of every circle.Using the parameters,we calculated their gravity,buo-yancy in the sea water.With the movement of ocean current,we analyzed the influence of upwelling current on the 9 specimens.The results show that the small axis ratio of the Pseudoschwagerina,the stronger impact of upwelling current.Thus,the life style of the Pseudoschwagerina may change from the benthic to planktonic with the increase of hydrodynamic energy.When the hydropower was weak,they were benthic,and when the hydropower was strong,they should be floating.