广西六寨中泥盆世生物礁基底层内的Pseudomicroplasma—Cystiphylloides群落及其相关问题的探讨

分析记述的Ｐｓｅｕｄｏｍｉｃｒｏｐｌａｓｍａ—Ｃｙｓｔｉｐｈｙｌｌｏｉｄｅｓ群落，保存于广西六寨中泥盆统东岗岭组生物礁基底层内；至少由十一大门类的４９个居群组成；生物生活方式有六种；动物进食类型有四种；由三个营养级构成群落的营养结构；生物生活取食位置在垂向空间上具有四个层次；Ｐｓｅｕｄｏｍｉｃｒｏｐａｓｍａ、Ｃｙｓｔｉｐｈｙｌｌｏｉｄｅｓ是优势生物和特征生物；底栖固着、悬食、中位生活取食层次、初级消费者营养级等为群落的主要生态特征。该化石群落所代表的原生群落，生存于中泥盆世吉维特期的早期，发育于水流畅通地势较为平坦的浅海陆棚环境（风暴浪基面以上的潮下带）。该化石群落的特征反映的是其原生群落中底栖动物群的生态特征。原生群落的消亡与群落演替有关。

PSEUDOMICROPLASMA-CYSTIPHYLLOIDES COMMUNITY FROM THE BASEMENT BEDS OF MIDDLE DEVONIAN REEF IN NANDAN,GUANGXI

The Pseudomicroplasma-Cystiphylloides Community (PC Community) were well preserved in the basement beds of a reef bioherm in the Donggangling Formation (Middle Devonian) in Liuzhai, Nandan County, northern Guangxi. The PC Community probably developed in the subtidal environment above the storm-wave base during the early Givetian Age.The disappearance of the community might be related to the communtity succession.The organisms in the PC Community include rugose corals, tabulate corals, chaetetids, strornatoporoids. brachiopods, gastropods, bivalves, trilobites, ostracods, polychaetes, bryozoans, crinoids, echinoids. algae and some unidentified boring organisms. The community consists of more than forty-nine benthic popualtions, of Which Pseudomicroplasma and Cystiphylloides are dominant and characteristic organisms. Among these organisms, six life styles (sessile, free-lying, encrusting, crawling, vagole and boring), four feeding groups (suspension feeders, fliter feeders, deposit feedersand carnlvores) and three trophic levels (producers, primary consumers and secondary consumers) may be recognized. These benthic consumers were positioned at four different levels (basal, lower, middle and upper) of water column above the substrate for feeding.Benthic sessile,suspension,middle position and secondary consumers are the main ecological features of the PC Community.