长江流域肋木属化石的研究及水韭目分类系统  

Studies on Pleuromeia from Middle Triassic Along th e Yangtze River Valley and Systematics of Isotales

作　　者：孟繁松[1] 

机构地区：[1]中国地质科学院宜昌地质矿产研究所

出　　处：《地球学报（中国地质科学院院报）》1999年第2期215-220,T002,共7页Acta Geoscientia Sinica

基　　金：国家自然科学基金

摘　　要：肋木属（Ｐｌｅｕｒｏｍｅｉａ）是三叠纪早、中期最重要的石松植物之一。文中描述了长江流域中三叠世肋木属化石２个种，查明了安尼期早期它们在本区几乎是同时出现的，此后期分布区由东向西逐渐缩小，植物分布区缩小的原因很可能与当时海平面升降有关。依据肋木属的产出层位和共存的海相化石认为，肋木属的地质时限为印度期—安尼期，安尼期末为全球肋木属生命危机期。从生物演化和演变过程中的质变标志出发，建立和完善了水韭目分类系统，水韭目包括肋木科和水韭科，前科包括肋木属和古水韭属，后科包括脊囊属。The genus Pleuromeia is one of the most im portant Lycopsids during Early Middle Triassic. In recent years, two species of Pleuromeia , P. sanxiaensis Meng and P. marginulata Meng, have b een fou d from the Middle Triassic in the Yangtze River valley. The distribution of Pl euromeia here reveals following characteristics:it might be almost simultaneou s in the Yangtze River vally during early Anisian. The shrinking cause of the di stributive area is related to the marine regression which occurred cyclically fr om east to west on the Yangtze Platfrom at that time. According to the horizon b earing Pleuromeia and the coexisting Vertebrate and marine fossils, the geo logical range of Pleuromeia is known to be from Induan to Anisian. It certai nly west the extinct way in the Yangtze River valley by the end of Anisian, whic h is roughly accordant with the life crisis of the Pleuromeia in the world. In addition, the systematic problem of Isotaceae is also minulely discussed in this paper. Based on the evolutional characteristics and the qualitative changes on the evolutional course of Isotales, this order is suggested to be composed of both Pleuromeiaceae and Isotaceae. The former contains bot h Pleuromeia and Nathorstiana ; the latter includes Annalepis, Skilliostrobus and Isotes .

关 键 词：长江流域 中三叠世 肋木化石 水韭目 分类系统 

分 类 号：Q914.651[天文地球—古生物学与地层学]