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1.
河南固始早石炭世杨山组植物群   总被引:6,自引:0,他引:6  
吴秀元 《古生物学报》1992,31(5):564-584
系统描述了扬山组植物18属25种,其中以石松类及种子蕨和真蕨纲为主,仅少数属楔叶纲;石松类中发现不少叶座较小,叶痕相对较大的鳞木类植物,颇似华夏植物群中的鳞木类;首次报道了我国发现的古芦木孢囊穗.据对植物群综合分析,杨山组的时代为早石炭世中晚期.  相似文献   

2.
河南东南部早石炭世植物群   总被引:4,自引:0,他引:4  
研究了河南东南部商城和固始杨山组植物化石,共计11 属18 种。它们分属于石松纲、楔叶纲、真蕨纲、种子蕨纲、科达纲和裸子植物种子,其中以石松纲鳞木类植物占优势。杨山组植物群含有一些典型的早石炭世分子, 如 Archaeocalam ites scrobiculatus、Cardiopteridium spetsbergense、Rhodeopteridiumhsianghsiangense,它们在维宪期至纳缪尔早期地层是颇为常见的;然而这一植物群也含有某些华夏型的鳞木类植物,即Lepidodendron cf.aolungpylukense、L.shanyangense、L.cf.subrhom bicum 等。根据植物群的总体组成,杨山组植物群的地质时代属于早石炭世晚期,大致相当于维宪晚期至纳缪尔A期。当前植物群可以与甘肃东部、陕西山阳、华南和马来西亚西部等的一些同期植物群进行对比,对比结果表明与陕西山阳植物群最接近。此外,笔者还讨论了全球早石炭世晚期植物群的分布  相似文献   

3.
研究内蒙古准格尔旗黑岱沟太原组上部6号煤层3个煤样中的孢粉,共发现孢粉27属43 种,包括藻类胞囊3属3种,称之为Punctatosporites minutus-Thymospora thiessenii-Laevigatosporites minutus组合.组合以蕨类植物孢子占绝对优势(98%),其中以真蕨类(尤其辉木Psaronius之类)的小单缝孢子(约>50%)为主,种子蕨次之,楔叶类居第三位,乔木石松类孢子和科达类花粉极少.这种情况在华北"太原期"甚至整个二叠纪煤层中不同程度地普遍存在,与华北几个地点已知煤核中植物化石以鳞木类或/和科达类占优势形成鲜明反差,也与欧美区晚石炭世早期煤层孢粉有重要区别,但却与美国晚石炭世晚期(Stephanian)煤层孢粉植物群近似.结合已有原位孢子资料,推论有关母体植物的古生态和华北二叠纪的成煤植物,并尝试解析形成上述反差的原因.  相似文献   

4.
对甘肃华亭延安组植物化石进行了宏观形态和表皮构造分析,经鉴定共有24属49种。该植物群组成为:真蕨纲(28.6%)、银杏纲(38.8%)繁盛,松柏纲(16.3%)、楔叶纲(8.2%)和苏铁纲(4.1%)占一定比例,石松纲和种子蕨纲未见。与国内、外侏罗纪植物群或组合,特别是与我国北方中侏罗世11个研究较为系统的植物群进行了详细的对比和分析。结果表明,当前植物群明显具有中国北方Coniopteris-Phoenicopsis植物群早期组合的特点,其地质时代归为中侏罗世早期,大致相当于阿林期(Aalenian)至巴柔期(Bajocian)。华亭延安组化石植物以温暖湿润气候下繁盛的植物类型为主,兼具少数亚热带、热带气候下的植物成分,说明甘肃华亭地区中侏罗世为偏湿润的暖温带气候。  相似文献   

5.
报道了产于中国二叠纪煤核中的3种具解剖构造的鳞木类叶,它们都具双木质部束,与似封印叶属(Sig-illariopsis Scott)特征一致,与该属已有种进行了对比,确定它们为3个新种:产于山西太原西山煤田太原组上部7号煤层(早二叠世早期)煤核中的山西似封印叶(Sigillariopsis shanxiensis sp.nov.)和太原似封印叶(S.taiyuanensis sp.nov.)以及产于贵州水城矿区汪家寨组1号煤层(晚二叠世晚期)煤核中的贵州似封印叶(Sigillariopsis gruizhouensis sp.nov.)。根据煤核中共生的鳞木类植物其他器官以及欧美植物区鳞木类植物的研究资料推断,它们可能属于封印木属(Sigillaria Brongniart)的叶,在国外(主要是欧美植物区),封印木属植物主要分布于石炭纪,见于二叠纪的封印木很少,华夏植物区的封印木属过去很少发现,其叶和生殖器官均未报道过,本是首次报道华夏植物区具解剖构造的封印木属的叶,它们的发现不仅丰富了华夏植物区封印木属植物的内容,而且对于研究封印木属的演化以及华夏植物区与欧美植物区鳞木类植物之间的关系也具有重要的意义。  相似文献   

6.
报道了产于中国二叠纪煤核中的3种具解剖构造的鳞木类叶,它们都具双木质部束,与似封印叶属(Sigillariopsis Scott)特征一致.与该属已有种进行了对比,确认它们为3个新种:产于山西太原西山煤田太原组上部7号煤层(早二叠世早期)煤核中的山西似封印叶(Sigillariopsis shanxiensis sp. nov.)和太原似封印叶(S. taiyuanensis sp.nov.)以及产于贵州水城矿区汪家寨组1号煤层(晚二叠世晚期)煤核中的贵州似封印叶(Sigillariopsis guizhouensis sp.nov.).根据煤核中共生的鳞木类植物其他器官以及欧美植物区鳞木类植物的研究资料推断,它们可能属于封印木属(Sigillaria Brongniart)的叶.在国外(主要是欧美植物区),封印木属植物主要分布于石炭纪,见于二叠纪的封印木很少.华夏植物区的封印木属过去很少发现,其叶和生殖器官均未报道过.本文是首次报道华夏植物区具解剖构造的封印木属的叶,它们的发现不仅丰富了华夏植物区封印木属植物的内容,而且对于研究封印木属的演化以及华夏植物区与欧美植物区鳞木类植物之间的关系也具有重要的意义.  相似文献   

7.
报道了产于中国二叠纪煤核中的 3种具解剖构造的鳞木类叶 ,它们都具双木质部束 ,与似封印叶属 (Sigil lariopsisScott)特征一致。与该属已有种进行了对比 ,确认它们为 3个新种 :产于山西太原西山煤田太原组上部 7号煤层 (早二叠世早期 )煤核中的山西似封印叶 (Sigillariopsisshanxiensissp .nov .)和太原似封印叶 (S .taiyuanensissp .nov .)以及产于贵州水城矿区汪家寨组 1号煤层 (晚二叠世晚期 )煤核中的贵州似封印叶 (Sigillariopsisguizhouensissp .nov .)。根据煤核中共生的鳞木类植物其他器官以及欧美植物区鳞木类植物的研究资料推断 ,它们可能属于封印木属 (SigillariaBrongniart)的叶。在国外 (主要是欧美植物区 ) ,封印木属植物主要分布于石炭纪 ,见于二叠纪的封印木很少。华夏植物区的封印木属过去很少发现 ,其叶和生殖器官均未报道过。本文是首次报道华夏植物区具解剖构造的封印木属的叶 ,它们的发现不仅丰富了华夏植物区封印木属植物的内容 ,而且对于研究封印木属的演化以及华夏植物区与欧美植物区鳞木类植物之间的关系也具有重要的意义。  相似文献   

8.
在2004年出版的《湖南植物志》中收录有标本考证的湖南省石松类和蕨类植物683种41变种10变型[1],截至2014年底,又陆续发表了70余个新记录[2-9]。2013年出版的《Flora of China》结合现代分子系统学和最新的研究成果,对大量植物物种进行归并和科属的重新划分,作为湖南省优势科属资源的一些种类数量也相应减少,如水龙骨科( Polypodiaceae)的鳞果星蕨属( Lepidomicrosorium Ching et K. H. Shing )和盾蕨属( Neolepisorus Ching ),鳞毛蕨科( Dryopteridaceae)的复叶耳蕨属( Arachniodes Blume)以及以武陵山区为中心分布的黔蕨属( Phanerophlebiopsis Ching)(归并到复叶耳蕨属Arachniodes Blume)等,书中仅记录湖南省分布的石松类和蕨类植物约434种(含变种、亚种和杂种)[10],数量相对较少,而湖南省分布的一些较珍稀的蕨类植物未有罗列,如川黔肠蕨也Diplaziopsis cavaleriana ( Christ) C. Chr.页、中华双扇蕨( Dipteris chinensis Christ )、全缘燕尾蕨也Cheiropleuria integrifolia ( D. C. Eaton ex Hook.) M. Kato页、睫毛蕨也Pleurosoriopsis makinoi ( Maxim. ex Makino) Fomin页[1]和心叶薄唇蕨也Leptochilus cantoniensis ( Baker) Ching页等[11]。作者根据近十年的相关文献[1-9,12],对湖南省分布的石松类和蕨类植物进行了梳理,统计出631种27变种2亚种和2杂种。自2013年开始,作者对湖南省东南部的莽山、西部的小溪以及西北部的八大公山等多个国家级自然保护区进行了野外考察,发现了湖南省石松类和蕨类植物新记录6种,分属于5科6属,它们的生境及形态特征见图1。凭证标本保存于上海辰山植物标本馆( CSH )。其中一些种类分布的海拔较低,对于湖南省蕨类植物区系特点、科属结构以及物种多样性演化等研究具有潜在价值。  相似文献   

9.
晚古生代瓢叶目植物的古生态学探讨   总被引:2,自引:0,他引:2  
对已知瓢叶目植物生态信息较为全面的观察分析表明 ,华夏植物群中瓢叶目植物的生态条件与欧美植物群较为相似。很可能 ,瓢叶目植物在欧美植物区和华夏植物区均可发育于水分充足的低地植物群和排水条件较好的高地植物群。对华夏植物群中某些低地群落的植物古生态样方统计分析结果显示 :一般情况下 ,瓢叶目植物的属种数量与植物群落中其它类群数量相比所占份额较少 (分异度不高 ) ,而它的个别种的数量则在群落中占据的比重较大 ,甚至占据优势地位 (丰度较高 )。从群落结构来看 ,瓢叶目植物所在的群落往往具有较好的分层结构。瓢叶目和某些楔叶纲、真蕨和种子蕨纲植物共同构成群落的林下层植被。群落的中、高层通常是石松纲和科达纲 。  相似文献   

10.
简要论述了近十年来泥盆纪石松类研究取得的主要进展。分支系统学研究增进了对石松类起源与谱系分异的认识,新构建的系统发育树中石松纲与真叶植物互为姐妹群,并识别出原始鳞木目和异孢石松类两个单系。基于化石数据库和定量统计分析,揭示了泥盆纪石松类的多样性演变模式:早泥盆世布拉格期(Pragian)石松类的属种数量显著增加,在埃姆斯期(Emsian)至艾菲尔期(Eifelian)逐步取代工蕨类,至晚泥盆世进一步辐射。依据华南、新疆及全球其他地区丰富的化石材料,大量泥盆纪的石松植物新类群得以建立,一系列已有属种得到详细的再研究,明确了这些植物的生物学特征,也促进了对石松类根系、生长和繁殖习性演化的深入理解。对华南早泥盆世的镰蕨类和挪威中—晚泥盆世乔木状石松的研究分别揭示了这一时期植物-土壤相互作用及热带森林群落面貌,为了解早期维管植物对地球环境和陆地生态系统的影响提供了新的资料。  相似文献   

11.
祁连山和河西走廊区石炭纪地层发育,动植物化石丰富,是研究我国海陆交互相石炭系的重要地区。臭牛沟组系袁复礼(1925)所建,标准地点在甘肃武威西南35km的臭牛沟,据其中的腕足类和珊瑚化石的研究,确定其时代为早石炭世维宪期(Visean)。研究材料来自甘肃景泰和靖远的早石炭世臭牛沟组,这里的臭牛沟组厚约120m左右,由泥质页岩夹煤线、粉砂岩及薄层泥灰岩、灰岩组成,为潮间潟湖相至滨海沼泽相及泥炭沼泽相沉积。含丰富的植物化石,主要分子有Sublepidodendron sp. , Lepidodendronciyaoense sp. nov. , Lepjingyuanense sp.nov. , Lepidodendron volkmannianum , Lep. gansuense sp. nov. , Lep. shanyangense, Lep. cf. aolungpulukense,Lep. sp. 1, Lep. sp. 2, Cathaysiodendron jingyuanense, C. cf. incertum, Stigmaria ficoides, Lepidostrobophyllum cf. lanceolatum, L. rotundi folium sp. nov., Lepidostrobus sp. 1, L. sp. 2, Bothrodendron ruchengense, Archaeocalamites scrobiculatus , Hamatophyton uerticillatum , Cardiopteridium spetsbergense , C. podozamioides,Triphyllopteris collombiana , Triphyllopteris sp. ( cf. T. lescuriana Lesquereux), Rhacopteris sp. , Adiantites gothanii, Sphenopteris sp. 1, Sphenopteris sp. 2, Rhodeopteridium hsianghsiangense, R. cf. hsianghsiangense,R. cf. chinghaiense, Rhodeopteridium sp. (cf. R. lipoldi) , Paripteris gigantea , P. cardiopteroides, Linopteris sp. , Codonospermum sp. , Trigonocarpus spp. , Cardiocarpus cordai, Cordaites sp. (cf. C. schenkii Halle) 。其下伏地层前黑山组中有菊石Kazakhstania sp.,为下石炭统底部Gattendor fia带分子,其余还有孢子化石、腕足类和植物,表明为杜内期沉积;而上覆地层靖远组底部有牙形石Gnathodus bilineatus bollandensis,G.bilineatus bilineatus,Paragnathodus commutatus及P.nodosus,是我国下石炭统顶部德坞阶的一个牙形石带化石;筵化石:Mediocris breviscula,M.pilatus,M.cf.minima,Eostaffella galinae,E.cf.mediocris是我国和卅l组常见分子,也产于贵州罗甸的德坞阶(相当于早期纳缪尔阶)。臭牛沟组产有大量孢子,可分3个孢子带,分别可以和西欧维宪期孢子带(PV,TC,NM)对比。在当前的植物群中Cathaysiodendron及Bothrodendron ruchengense,Le pidodendron shanyangense的发现,对于研究早石炭世植物地理区的划分,华南和西北同期植物群的对比及东方型鳞木类的演化均具有重大意义。  相似文献   

12.
The fossil plants described and illustrated were collected from the Yangshan Formation in Shangcheng and Gushi districts of southeastern part of Henan Province, namely, Lepidodendron cf. aolungpylukense Sze, L. shanyangense Wu et He, L. . cf. subrhombicum Gu et Zhi, L. sp. a, L. sp. b, Bothrodendron sp. a, B. sp. b, Lepidostrobus ? sp., Stigmaria ficoides (Sternberg) Brongniart, Archaeocalamites scrobiculatus (Schlotheim) Seward, Cardiopteridium spetsbergense Nathorst, Triph yllopteris ? sp., Rhodeopteridium hsianghsiangense (Sze) Zhang, Zhao et Wu, Paripteris cf. pseudogigantea (Potonie) Gothan, P. ? sp., Cordaites schenkii Halle, Cardiocarpus cordai (Geinitz) Gu et Zhi and Carpolithus sp., including 18 species in 11 genera. They belonged to Lycopsida, Sphenopsida, Filices, Pteridospermopsida, Cordaitopsida and Semina Gymnospermarum respectively , in which Lepidophytic plants of Lycopsida were the dominanance. The Yangshan Formation flora contains some typical Early Carboniferous elements, such as Archaeocalamites scrobiculatus, Cardiopteridium spetsbergense and Rhodeopteridium hsianghsiangense, which were fairly common from Visean to early Namurian; however, it also includes certain lepidophytic plants of the Cathaysian type, such as Lepidodendron cf. aolungpylukense, L. shanyangense and L. cf. subrhombicum, etc. On the basis of the floral composition, the geological age of the Yangshan Formation flora belonged to the late Early Carboniferous epoch, corresponding approximately to late Visean to early Namurian A. The present flora could be compared with contemporaneous floras from eastern Gansu, Shanyang of Shaanxi, South China and western Malaysia, which was closest to the Shanyang flora. In addition, the authors also discussed the distribution of late Early Carboniferous floras in other parts of the world.  相似文献   

13.
吴秀元  王军 《古生物学报》2004,43(4):489-501
记述的两种新植物分别来自秦岭地区的凤县和镇安县。产于凤县草凉驿红花铺草凉驿组的Adiantites honghuapuensis sp.nov.,至少二次羽状复叶,羽片线形,以宽角着生于羽轴上;小羽片椭圆形,羽片基部的小羽片偶尔分裂为2—3个裂片。小羽片基部收缩,有短柄或以较宽的基部着生于羽轴上,扇状脉。另一产自镇安县茅坪东山梁二峪河组的Qinlingopteris orientalis gen.et sp.nov.,其特征是二次羽状复叶,末二级羽轴与末级羽轴夹角较小,大约30^#左右。小羽片亚对生,长卵形或亚圆形,顶端较窄,中部较宽,基部较狭并具短柄;叶脉扇状;羽轴上具间小羽片,间小羽片与正常小羽片等形同大。草凉驿组的地质时代大致为纳缪尔期至维斯发早期,而二峪河组则为早石炭世维宪期。  相似文献   

14.
This paper deals with the Fossil Plants from Upper Permian in Northern Xinjiang. These plants include 25 species of 15 Genus. Five new species is all described in this paper. These are: ?Supaia serrata sp. nov. Tychtopteris densinervis sp. nov., Ty. obesa sp. nov., Comia Cangfanggouensis sp. nov. and Lepeophyllum ovatum sp. nov. These are all new to science, found in the Lower Cangfanggou Group in Northern Xinjian, of Late Permian in age. Some fossils Lobatannularia multifolia Ken'no, Sphenopteris rotunda Sze and Alethopteris huiana Lee found in this group are known in the Cathaysian Flora. Others are common in the Angara Flora, such as Stellotheca sehtchurowskii (Schmal.) Surange et Prakash, Sphenopteris, adzvensis Zal., Tychtopteris cuneata (Schmal.) Zal. Noeggerathiopsis sp., ect. That indicates in the Lower Cangfanggou Group is a transitional zone between the Angara and the Cathaysian floras.  相似文献   

15.
本文对华夏植物群鳞木属植物的研究现状进行了综述,讨论了华夏木属是否废除的问题。根据华夏木属与鳞木属基本特征相同,只是叶座形态、叶痕形态与鳞木属不同,这些特征只能作鳞木属分种的依据,同意《中国古生代植物》的处理意见。本文还描述了河南禹县山西组鳞木属的两个新种,即:Lepidod endron huayanense Ma(spnov.), L. yuxianense. Ma(sp. nov.).  相似文献   

16.
This paper deals with some Middle Jurassic fossil plants from southern margin of the Eerduosi Basin. There are 36 species in 13 genus in this flora, i.e. Equisetum multi- dentatus Oishi, E. sp., Coniopteris hymenophylloides (Brongn.) Seward, C. bella Harris, C, burejensis (Zalessky) Seward, C. szeiana Choweet Yeh, C. tatungensis Sze, C. spp., Todites williamsoni (Brongn.) Seward, T. cf. williamsoni (Brongn.) Seward, Cladophle- bis asiatica Chow et Yeh, C. argutula (Heer) Fontaine, C. hsiehiana Sze, C. ( Gleichenites) takeyamae Oishi et Takahasi, C. cf. gracils Sze C. triangularis Oishi, C. grabauiana P’an C. cf punctata (Thoms) Chow et Yeh, C. spp., Baiera cf. concinna (Heer) Kawasaki, B. furcata (L. et H.) Braun, B. sp., Sphenobaiera longifolia (Pomel) Florin, Ginkgo obrutchewi Seward, G. sp., Phoenicopsis angustifolia Heer P. manchurica (Yo- koyama) Yabe, p. sp., Czekanowskia rigida Heer, C. sp., Pterphyllum sp., Elatocladus cf manchurica (Yokoyama) Yabe, E. sp., Podozamites lanceolatus (L. et. H.) Braun P. sp., Carpolithus sp. etc. The dominant groups of this flora are Filicopsida and Ginkgopsida. So it could be compared with the flora of Yanan Formation from inner Earduosi Basin and other floras from Northeast, Northwest and China, such as the floras of Dutung, Mentougon and Dongsheng etc. This flora is different from the Late Triassic flora and the Early Jurassic flora of North China. It belongs to the Coniopteris-Phoenicopsis flo- ra, which was assigned to Early-Middle Jurassic flora by Prof. Sze. But after studying, the authers believe that this flora should belong to Middle Jurassic rather than Early Jurassic. The climate was warm and damp in that time in North China.  相似文献   

17.
This paper deals with the fossil plants from Gutian Formation in Lianyang, Guangdong, totaling 14 genera and 18 species. They are: Paracalamites sp., Annularia pinglogensis (Sze) Gu et Zhi, Lobatannularia cathaysiana Yao, L. Multifolia Kon’on et Asama, L. sp., Schizoneura wangtangiana sp. nov., Pecopteris hemitelioides Brongn., P. valida sp. nov., Cladophlebis vavia sp. nov., Danaeites guangdongensis sp. nov., Ptychocarpus unauriculatus sp. nov., Odontopteris plicatoides sp. nov., Neuropteridiopsis longovata gen. et sp. nov., Compsopteris contracta Gu et Zhi, Gigantonoclea crassa sp. nov., Gigantopteris ?nicotianaefolia Schenk, G. parvipinnulata sp. nov. and Rhipidopsis sp. Among them one new genus, 9 new spp. and 2 undetermined spp. are described. According to the fusulinids lived in the late Early Permian era are descovered at the top of this Formation, the geological era of present flora must not be later than late Early Permian. Therefore, the geological era of Gutian Formation are certain to be the Late Early Permian.  相似文献   

18.
本文描述和讨论广东连阳地区谷田组地层的化石共14属18种,即:Paracalamites sp.,Annularia pingloensis(Sze)Gu er Zhi、Lobatannularia cathaysiana Yao、L.multifoliaKon'on et Asama、L.sp.、Schizonerua wangtangiana sp.nov.、Pecopteris hemitelioidesBrongn.、P.valida sp.nov.、Cladophlebis varia sp.nov.、Danaeites guangdongensis sp.nov.、Ptychocarpus unauriculatus sp.nov.、Odontopteris plicatoides sp.nov.、Neuropteri-diopsis longovata gen.et sp.nov.、Compsopteris contracta Gu et Zhi、Gigantonoclea cra-ssa sp.nov.、Gigantopterts?nicotianaefolia Schenk、G.parvipinnulata sp.nov.和 Rhipido-psis sp.等,其中有1新属、9新种和2未定种。谷田组顶部发现了早二叠世晚期的(竹蜓)类层,下段则与下伏的茅口组假整合。植物群的地质时代为早二叠世晚期。  相似文献   

19.
ORDOVICIAN NAUTILOID FAUNA FROM LUNSHAN, JURONG, JIANGSU   总被引:1,自引:0,他引:1       下载免费PDF全文
The fossil nautiloids described in this paper were collected in 1984 and 1985 from Lunshan, Jurong in Jiangsu; there the Ordovician strata are well developed and may be divided in descending order into seven formations as follows:Upper Ordovician: Wufeng Formation Tangtou FormationMiddle Ordovician Pagoda Formation Lower OrdovicianKuniutan FormationDawan FormationHunghuayuan FormationLunshan FormationThese nautiloids comprise 36 species belonging to 13 genera (including one new genus and 11 new species), namely,Middle OrdovicianPagoda FormationSinoceras chinense (Foord), Michelinoceras changjiangense Chen, densn (Y), M. paraelongatum Chang.Lower OrdovicianKuniutan FormationRhynchorthoceras jurongense sp. nov., R. lunshanense sp. nov., Dideroceras wahlenbergi (Foord), D. holmi Flower, Michlinoceras irregulare sp. nov., Kotoceras gaoluncunense sp. nov.Dawan Formation.Cochlioceras yantzeense Chang, Chisiloceras ichangense Wang, C. yaoshanense Qi, C. changyangense (Chang), Protocycloceras deprati Reed, P. hupehcnse (Shimizu and Obata), P. sichuanense Wang, P. remotum Lai, P. gangshanense sp. nov., P. siphosedimentum Pan, P. chaoi sp. nov., P.shishantouense sp. nov., P. gaojiabianense sp. nov., Changyangoceras gaojiabianense sp. nov., Gangshanoceras jurongense gen. et sp. nov., G. densum gen. et sp. nov., Michelinoceras cf. dayongense Lai, Troedssonella lunshanensis sp. nov., Mesosendoceras leei (Y), Vaginoceras peiyangense malukonense Chen, Dideroceras mui (Chang), D. gaoluncunense sp. nov.  相似文献   

20.
Abstract:  The sections of Germig in the Nyalam area, southern Tibet, provide a continuous exposure of ammonoid-bearing, uppermost Triassic and basal Jurassic strata. Eighteen species (three of them new) are described and illustrated: Choristoceras marshi Hauer , C. aff. marshi, C. cf. nobile Mojsisovics , C. nyalamense sp. nov., Eopsiloceras germigense sp. nov. , Pleuroacanthites aff. biformis (Sowerby) , Rhacophyllites sp., Nevadaphyllites cf. psilomorphus (Neumayr), Neophyllites sp. indet., Neophyllites cf. biptychus (Lange), Psiloceras tibeticum sp. nov., P. calliphyllum (Neumayr), Euphyllites cf. struckmanni (Neumayr), Discamphiceras pleuronotum (Canavari), Alsatites spp., Kammerkarites frigga , and K. sp. The ammonoid fauna shows a strong affinity to that of the Northern Calcareous Alps, although diversity in the Calliphyllum Zone is markedly lower. The ammonoid succession across the Triassic/Jurassic boundary is subdivided into four zones: the Rhaetian Marshi, the basal Hettangian Tibeticum, the lower Hettangian Calliphyllum, and the middle Hettangian Pleuronotum zones. It is the only known succession across the Triassic/Jurassic boundary in the Tethyan Realm that is not condensed. The Marshi and Calliphyllum zones are correlated with the same zones in the Northern Calcareous Alps. The Tibeticum Zone, a new local zone, is transitional between the Marshi and the Calliphyllum zones in that it yields both choristoceratids and psiloceratids. Its base is taken to mark the base of the Jurassic System in the eastern Tethys.  相似文献   

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