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1.
贵州寒武纪杷榔动物群的海绵动物是近年在剑河辣子寨村发现的新类群。辣子寨剖面的海绵动物组合多样性高,化石保存好。经鉴定有普通海绵纲细丝海绵科的Leptomitus tereticusculus Chen et al.,1989,Leptomitus cf.L.conicus García-Bellido et al.,2007和Paraleptomitellasp.,斗篷海绵科的Choiaellacf.C.ovataZhao and Yang in Yang et al.,2003和Choiasp.;六射海绵纲的Saetaspongiasp.,计有5属6种和一些属种待定的海绵化石。剑河辣子寨村杷榔组海绵类群的发现丰富了杷榔动物群的组成面貌,扩展了寒武纪第四期海绵动物的古地理分布区,增加了寒武纪第四期海绵动物分异演化的信息,为海绵动物分类学、古生态学和埋藏学研究提供了新材料。  相似文献   

2.
贵州剑河辣子寨村辣子寨剖面杷榔组的杷榔动物群是近期发现的一个化石丰度较高且较复杂多样的动物群。该产地的化石库含有两个化石富集的层位,即下化石层和上化石层。通过对两个化石富集层的岩石结构、构造、沉积特征、生物类群组成及化石丰度和保存特征等方面的分析研究表明,下化石层与上化石层内化石组合和埋藏特征存在较大差异。下化石层类群组成多样、化石丰度较高,以掘头虫类三叶虫、三叶形虫Naraoia、大型双瓣壳节肢动物Isoxys、Tuzoia及古蠕虫、海绵等为主,且化石主要保存在事件沉积层内,保存质量较好,为外陆棚沉积环境下大量生物个体发生原位快速沉积埋藏作用形成。而上化石层内化石以具硬壳的三叶虫为主,有较大的埋藏量,少量或碎片状的Naraoia,Isoxys,且这类化石数量少,主要在背景层中保存,可能为静水沉积时,沉积界面积累了大量生物遗体并暴露于基底表面一定时间后,再被沉积物逐渐堆积掩埋而形成,为生物遗壳的原位或近原位埋藏。  相似文献   

3.
Sphenothallus Hall, 1847是刺胞动物中以细长锥管状为特征, 底栖固着的一个属, 始现于寒武纪延伸至二叠纪。之前该属在贵州寒武纪的牛蹄塘生物群、剑河生物群和凯里生物群中均有报道。位于寒武纪第4阶的杷榔生物群也发现该属的化石, 杷榔生物群的SphenothallusS. kozakiS. kozaki? 2个种组成。杷榔生物群的时代位于牛蹄塘生物群和剑河生物群之间, S. kozaki之前仅出现在捷克Jince组和中国湖北石牌组。杷榔生物群Sphenothallus的发现增加了该属在寒武纪第4期刺胞动物的多样性古生态、古地理分布及演化信息, 丰富了杷榔生物群底栖固着类群的组合面貌。  相似文献   

4.
湘西北寒武系杷榔组出露较好,三叶虫化石十分丰富。文中报道描述了在花垣县排吾乡两个剖面的杷榔组泥页岩中采得的三叶虫两属两种Dinesus bura(Qiu,1980)和Eosoptychoparia guizhouensis Yuan in Zhang et al.,1980。本次研究将双岛虫属Dinesus在中国的地层延限下延至杷榔组(寒武系第二统第四阶)的中下部。这些新材料在湖南杷榔组的发现,扩大了这两属的地理分布范围,并提供了更多本区与其他地区的地层进行对比的材料。以上新发现更进一步丰富了寒武纪江南斜坡带杷榔组三叶虫动物群的内容。  相似文献   

5.
贵州东部下寒武统杷榔组上部的三叶虫   总被引:3,自引:0,他引:3  
贵州凯里市西北郊瓮岭塘寒武系都匀阶下部(下寒武统)杷榔组顶部和镇远县江古镇杷榔组上部的杷榔动物群,是新近发现的重要动物群。动物群由始海百合与莱德利基虫类三叶虫及多门类的化石组成,表明黔东早寒武世都匀期早期斜坡相生物的多样性。就属种而言,三叶虫类最为丰富,计有4属5种,1亚种和1未定种,包括莱得利基虫类的Redlichia(Pteroredlichia)chinensis,Redlichia(Pteroredlichia)chinensislui,Redlichia(Pteroredlichia)murakamii,耸棒头虫类Arthricocephaluschauveaui,Changaspisplacenta,Changaspismicropyge及褶颊虫类Probowmania(Probowmania)sp.。褶颊虫类Probowmania(Probowmania)的出现,丰富了黔东地区杷榔组上部三叶虫组合,层位明显下延。文章还报道Redlichia(Pteroredlichia)chinensis分节末期到成虫早期个体发育特征。  相似文献   

6.
贵州剑河寒武纪杷榔组辣子寨剖面含有丰度较高的古蠕虫类化石。化石鉴定为Wronascolex geyiensis, 主要保存在三个层位。在对三个层位的岩石、沉积特征、化石成因及埋藏特征探讨分析后, 证实W. geyiensis化石保存于快速的沉积事件导致的浊流沉积层内, 而化石埋藏的完美程度受到成岩过程中埋藏位置、沉积物中矿物结晶和充填方式的影响, 这些后期的成岩、成矿作用对先期形成的化石精细结构产生了直接和间接的破坏作用。本文通过对W. geyiensis化石体上黏土矿物、草莓状黄铁矿、自形–半自形黄铁矿的成因分析后, 获得最适合保存软躯体化石的环境应该为缺氧且生物体与孔隙水中的硫酸盐无接触的原地和近原地埋藏条件。  相似文献   

7.
王德智  彭进 《古生物学报》2018,57(4):429-443
始海百合类是贵州寒武纪杷榔动物群和凯里生物群代表性化石类群。产出杷榔动物群和凯里生物群的杷榔组和凯里组主要由灰绿色、灰色的泥、页岩组成,始海百合类化石保存在2个组中上部的泥、页岩中,化石保存好,丰度高,是陆棚斜坡较深水环境生态类群的典型代表。本文基于来自杷榔组的36块Guizhoueocrinus yui,29块Protogloboeocrinus yini标本,和凯里组的20块Sinoeocrinus lui,20块Globoeocrinus globulus标本,采用几何形态测量方法和传统形态测量方法,对每块标本萼部选定了4个界标点(landmark),进行数理统计和几何形态的定量分析。发现寒武纪始海百合类的萼部尺寸上差异较小,在形态上,杷榔组的Protogloboeocrinus yini和Guizhoueocrinus yui萼形相似,均偏细长形,而凯里组的Sinoeocrinus lui和Globoeocrinus globulus萼形差异较大,口部区域宽度均出现增大,萼茎连接处宽度则出现变大和变小两种趋势。结果说明:同一生态环境下寒武纪早期的Guizhoueocrinus yui,和中期的Sinoeocrinus lui的萼在演化上具连续性,细长的萼与长茎能够让始海百合个体更有效捕食上部水域的食物,而寒武纪早期的Protogloboeocrinus yini和中期的Globoeocrinus globulus的萼在形态上具有演化上的连续性。球状的萼配合粗短的茎,可以增强始海百合个体的稳定性,以适应更强的水动力环境,表明出现了生态位的扩张。  相似文献   

8.
寒武纪海洋中的双瓣壳节肢动物耙肢虾Occacaris Hou,1999曾被报导出现在云南澄江生物群和贵州凯里生物群中,延续了一个相对短的地质时间。本文报道了在贵州省剑河县辣子寨村杷榔组中上部发现的Occacaris。杷榔组的Occacaris以壳背缘和前腹边缘呈大角度相交为特征,不同于澄江生物群和凯里生物群发现的背缘和前腹边缘交角均小于90°角的O.oviformis Hou,1999和O.magnus(Yao,2009),应为一新种,命名为O.lazizhaiensis sp.nov.。O.lazizhaiensis sp.nov.在贵州杷榔组的发现表明起源于云南寒武纪早期扬子地台浅水区的Occacaris,在寒武纪早中期开始向贵州较深水区的杷榔组迁移,延续进入时代较晚的凯里组,为适应生态环境的改变,出现了体构上较大的差异。杷榔组Occacaris的发现增加了Occacaris分类学、生态学、古地理分布和演化发育的新信息。  相似文献   

9.
贵州东部寒武纪的杷榔组发育,化石丰富,含有杷榔动物群;其中掘头虫类、莱德利基虫类三叶虫保存好,序列完整,提供了研究这些类群属种个体发育的重要材料。本文据杷榔组Redlichia (Pteroredlichia) chinensis(Walcott,1905)的300多块标本的分析数据,详细讨论和重点研究了其从幼虫期、分节期至成虫期个体发育特征,分析各个阶段的形态变化及个体发育演化趋势。丰富了R.(Pteroredlichia) chinensis个体发育的资料,对莱德利基虫属种厘定起到积极的作用,提供了属种分类对比的重要证据。  相似文献   

10.
湘西北寒武系杷榔组出露较好,三叶虫化石十分丰富。文中报道描述了在花垣县排吾乡两个剖面的杷榔组泥页岩中采得的三叶虫两属两种Dinesus bura(Qiu,1980)和Eosoptychoparia guizhouensis Yuan in Zhang et al.,1980。本次研究将双岛虫属Dinesus在中国的地层延限下延至杷榔组(寒武系第二统第四阶)的中下部。这些新材料在湖南杷榔组的发现,扩大了这两属的地理分布范围,并提供了更多本区与其他地区的地层进行对比的材料。以上新发现更进一步丰富了寒武纪江南斜坡带杷榔组三叶虫动物群的内容。  相似文献   

11.
报道湖北秭归长江以南茅坪镇下茶庄剖面发现的寒武系下部(第2统第4阶)石牌动物群。该剖面石牌组出露良好,顶底界线清楚,总厚度208m。初步采集结果表明该剖面具有较大的开采潜力,化石数量上以腕足动物和软舌螺为主,同时还包括数量较多的三叶虫、双瓣壳节肢动物、开腔骨类和少量的鳃曳动物等,其中的腕足动物保存良好,数量丰度较大,壳体多以密集立体保存的内模形式出现,这是石牌组腕足动物大量壳体化石的首次报道。化石采集发现鳃曳动物与腕足动物可在相同的层面同时出现。与澄江动物群鳃曳动物化石相比,下茶庄剖面鳃曳动物的环纹保存的立体程度明显较强,但还未见到任何吻部和肠道结构保存。石牌动物群最早发现于长江以北宜昌三峡人家旅游风景名胜区内的王家坪剖面,但该地区石牌组覆盖严重,顶底未见出露,使王家坪剖面石牌动物群的后续研究存在较大困难。因此,石牌动物群在下茶庄剖面的发现和进一步采集和研究对深入揭示石牌动物群的组成、富集层位、群落结构和地理分布范围有重要的意义。  相似文献   

12.
To better understand temporal variations in species diversity and composition, ecological attributes, and environmental influences for the Middle Cambrian Burgess Shale community, we studied 50,900 fossil specimens belonging to 158 genera (mostly monospecific and non-biomineralized) representing 17 major taxonomic groups and 17 ecological categories. Fossils were collected in situ from within 26 massive siliciclastic mudstone beds of the Greater Phyllopod Bed (Walcott Quarry — Fossil Ridge). Previous taphonomic studies have demonstrated that each bed represents a single obrution event capturing a predominantly benthic community represented by census- and time-averaged assemblages, preserved within habitat. The Greater Phyllopod Bed (GPB) corresponds to an estimated depositional interval of 10 to 100 KA and thus potentially preserves community patterns in ecological and short-term evolutionary time.The community is dominated by epibenthic vagile deposit feeders and sessile suspension feeders, represented primarily by arthropods and sponges. Most species are characterized by low abundance and short stratigraphic range and usually do not recur through the section. It is likely that these are stenotopic forms (i.e., tolerant of a narrow range of habitats, or having a narrow geographical distribution). The few recurrent species tend to be numerically abundant and may represent eurytopic organisms (i.e., tolerant of a wide range of habitats, or having a wide geographical distribution). Rarefaction curves demonstrate variation in species richness through the GPB and suggest that more stenotopic species could still be discovered with additional sampling. Comparisons between richness and evenness trends suggest that the community is relatively stable overall, despite gradual species turnover through time, especially in assemblages from younger beds. Less diverse assemblages with low species evenness possibly represent the onset of less favourable environmental conditions.Fossil occurrences in individual beds were analysed using a range of statistical techniques (Correspondence Analysis, Canonical Correspondence Analysis, Minimum Spanning Tree, Indicator Species Analysis, Mantel Test) to extract community patterns. Results suggest the presence of four fossil assemblages based on distinct species associations. The different assemblages presumably reflect variations in environmental and ecological conditions, some acting through time, leading to species turnover. “Disturbances” (e.g., changes in paleo-redox conditions), differences in substrate firmness, and limited taphonomic biases are probably the main factors contributing to community structure. The influence of ecological factors, however, is also predicted from non-random patterns of species recurrences in successive events. Preliminary comparisons with Lower Cambrian Chengjiang-type assemblages of southern China suggest that the overall structure and ecology of Cambrian communities remained relatively stable until at least the Middle Cambrian in subtidal siliciclastic soft substrate environments.Comparisons with modern marine benthic ecosystems further suggest the Burgess Shale community was probably highly dependent on immigration from a regional pool of species after each burial event. This could support the view that species availability, habitat characteristics, and recolonisation processes were more important in structuring the community in the long-term than species interactions or environmental variations at a local scale.  相似文献   

13.
熊志凤  季承 《古生物学报》2023,62(1):169-182
巢湖动物群主要分布在安徽巢湖及邻近地区下三叠统奥伦尼克阶南陵湖组中上段地层中,以保存大量完整且精美的巢湖龙化石为特点,伴生有鳍龙类、鱼龙形类、鱼类及多门类的海生无脊椎动物。巢湖动物群的研究始于20世纪70年代,近年来基于巢湖动物群中大量新材料的系统研究为二叠纪–三叠纪大灭绝发生之后三叠纪海洋生态系统的快速复苏过程提供了新的依据。本文梳理了巢湖动物群的地质背景、研究简史、生物组合特征、地层分布与时代特征、稳定同位素地球化学等方面取得的进展,并就其群落生态组成进行初步探讨。这项工作对建设巢湖动物群相关国家地质公园、开展科普教育工作、旅游开发等有着积极的意义。  相似文献   

14.
辽宁凌源及相邻内蒙古南部宁城地区义县组发现多个重要脊椎动物化石地点,通过岩 石地层、脊椎动物生物地层和同位素年代地层对比,建立了该地区义县组地层层序。凌源一宁 城地区义县组有 2个脊椎动物化石层位:下部道虎沟层含 Lycopteraer Ichthyofauna, Psittacosaurus Fauna和Confuciusornis Avifauna等3个动物群,可以与北票尖山沟层的四合 屯脊椎动物化石群对比,层位相当于义县组一、三段;上部大王杖子(大新房子)层含 Lycoptera Ichthyofauna和Liaoxiornis Avifauna等2个动物群,为义县组中部沉积,在四合屯地 区缺失。冀北丰宁四岔口-森吉图地区义县组脊椎动物化石层对应于凌源大王杖子层;滦平 大北沟组为义县组最下部沉积,其上覆的大店子组相当于宁城道虎沟层和北票四合屯义县组 一、三段。热河群义县组和九佛堂组发现3个连续的鸟类群;义县组下部Confuciusornis Avifauna、义县组中部Liaoxiornis Avifauna和九佛堂组Cathayornis-Chaoyangia Avifauna。义 县组和九佛堂组Lycoptera I  相似文献   

15.
云南开远小龙潭动物群的性质及时代的进一步探讨   总被引:4,自引:2,他引:2  
本文在前人工作的基础上,结合新材料,对小龙潭动物群作了新的补充与论述.小龙潭动物群在组合面貌上与西瓦立克的 Chinji, Nagri 层动物群相近,动物群的时代不早于 Chinji 层而早于云南禄丰石灰坝动物群,为晚中新世.  相似文献   

16.
泥河湾盆地发现短喙象化石   总被引:1,自引:1,他引:0  
本文记述泥河湾盆地河北蔚县两个地点发现的化石,它们被鉴定为短喙象类的?Anancus和Pentalopodon两个属。  相似文献   

17.
Synopsis All living species occupy an ecological niche, and are positioned within a trophic hierarchy. Extinct organisms presumably held similar behavioral and coevolutionary characteristics in the past, and were susceptible to the same kinds of natural ecological pressures operating today. Paleoecological investigations are limited by the incompleteness of the fossil record, and particularly by a lack of behavioral data that are so fundamental to ecological studies of living communities and habitats. Opportunities to examine the coevolutionary structure of ancient communities from empirical data are extremely rare. One such opportunity is provided by the Lower Cretaceous Santana Formation of north-eastern Brazil, a series of richly fossiliferous strata approximately 110 million years old. Many fossil fishes from the Santana Formation contain identifiable prey, including decapod crustaceans and fishes. A trophic hierarchy of these organisms is reconstructed here, and their ecological relationships are discussed. Comparison is made with a similar fish fauna from the Upper Jurassic Solnhofen Limestone of Germany. Low-level, intermediate and high-level predators are identified in each fauna. Predator-prey relationships in the Santana fauna are strongly hierarchical, and are more focussed at the intermediate predator level than in Solnhofen. Comparison with a model of predator-prey relationships between fishes and benthic fauna of the Baltic Sea (which like the Araripe Basin represents a semi-enclosed environment) suggests that heavy predation on teleosts such asRhacolepis, occupying an intermediate trophic level, may have permitted benthic decapods to proliferate and exclude other benthic organisms. Less intense predation on fishes at the intermediate trophic level would allow their numbers to increase, thereby increasing the intensity of predation on the benthos at the base of the trophic hierarchy.  相似文献   

18.
Commonness of organisms typically fluctuates through time, and understanding such fluctuations has long been an important part of ecological research. Studies at paleontological timescales provide a perspective on how changes in population size might affect community structure over millions of years. To overcome the obstacle that population size parameters such as abundance are difficult to detect in the fossil record, we here used fossil locality coverage to approximate changes in site occupancy in the Neogene of Europe over the course of 20 million years. Our aim was to examine whether the trophic structure of mammalian communities is maintained through time despite continuing environmental change. Ecomorphological grouping of fossils indicates that herbivore genera have low taxon resilience in that each genus has predominantly only one locality coverage peak before disappearance. Despite this continuous replacement of the most prevalent herbivore genera, the herbivore trophic group as a whole remains the largest and maintains a roughly constant share of locality coverage throughout the Neogene. The successive herbivore genera, however, show increasing adaptations to harshening environments, indicating shifting properties of niches while the overall trophic structure is conserved. Carnivores, dependent on primary productivity for food indirectly through their prey, show moderate lack of resilience. In contrast, in omnivores changes in locality coverage are close to random fluctuations.  相似文献   

19.
中国三叠纪海生爬行动物化石研究的回顾与进展   总被引:2,自引:1,他引:1  
中国三叠纪海生爬行动物化石研究始于20世纪50年代,近10年来取得了重要的进展。此类化石在华南分布广泛,已见于多个省区的十余处地点,涉及自下三叠统奥伦尼克阶至上三叠统诺利阶的至少7个层位,并显示出由东向西产出层位逐渐升高的趋势。我国的三叠纪海生爬行动物化石门类齐全,属种丰富,已知类群包括鱼龙类、海龙类、檐齿龙类、始鳍龙类、原龙类、初龙类和湖北鳄类,显示出典型的西特提斯动物群特征,同时也体现了与东太平洋动物群的某些联系,以及一定的地方色彩。这些化石为研究三叠纪海生爬行动物各个类群的起源、演化和绝灭以及海洋环境的变迁提供了新的材料。  相似文献   

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