河北曲阳晚古生代植物群及古地理研究

在河北省曲阳石炭一二叠纪地层中发现古植物化石29属62种,包括真蕨纲和种子蕨纲、楔叶纲、石松纲、瓢叶纲、苏铁纲、种子化石、科达纲、银杏纲.此古植物群华夏植物群的特点明显,纵向上可划分成5个古植物组合;演化具有阶段性,组合的变化与古地理6个演化阶段相适应.     

内蒙古东胜煤田延安组侏罗纪植物群

为确定内蒙古东胜煤田延安组的地质时代,对东胜煤田钻孔中产出的大量古植物化石进行了详细研究和鉴定,该植物群组成包括节蕨纲、真蕨纲、种子蕨纲、苏铁纲、银杏纲、松柏纲的25属68种,以真蕨纲、银杏纲为主,其次为苏铁纲和松柏纲,节蕨纲和种子蕨纲较为少见。可建立Coniopteris（锥叶蕨）-Cladophlebis（枝脉蕨）植物组合,并可进一步划分为2个亚组合：延安组一段的Coniopteris（锥叶蕨）-Neocalamites（新芦木）亚组合和延安组二段的Cladophlebis（枝脉蕨）-Phoenicopsis（拟刺葵）亚组合。经与国内、外其它地区植物群对比,延安组一段的地质时代为早侏罗世晚期土阿辛期,延安组二段的地质时代为中侏罗世早期阿林期和巴柔期。     

东胜煤田侏罗系延安组植物群及古气候分析

应用放大镜观察的方法对东胜煤田侏罗系延安组中保存的大量植物化石进行分析,共鉴定出24属64种.在此基础上,对侏罗系延安组植物群组合特征及其所反映的古气候进行研究.结果表明:该植物群可分为有继承性的Coniopteris szeiana-Nilssonia pterophylloides-Eboracia lobifolia与Neocalalamites hoerensis-Podozamites lanceolatus上下两个组合;该植物群与北京门头沟植物群、豫西义马植物群主要属种相同,都是银杏纲、真蕨纲占优势,并以蚌壳蕨科的繁盛为特征,均属于我国北方地区早、中侏罗世Coniopteris-Phoenicopsis植物群,可进行对比;植物群组合特征反映东胜煤田延安组时期为季节分明、偏潮湿的温带-暖温带气候.     

兰州阿干镇煤田下侏罗统大西沟组植物化石的特征及时代

研究表明,兰州大西沟组植物群与苏联中亚伊塞克—库尔地区早侏罗世早期植物组合最为相似,两者都以具大型小羽片的枝脉蕨(Cladophledis)高度繁荣为特色.大西沟植物群与我国南方同期植物群有较大差异.银杏类和苏铁类植物在组合中所占比例的高低以及锥叶蕨(Coniopteris)的是否存在,可能是鉴别我国北方早侏罗世早、晚两期植物组合的重要标志.     

极小种群植物玉龙蕨的群落调查及生态位分析

为了更加全面的了解掌握极小种群野生植物玉龙蕨的群落构成及特征,通过对云南省迪庆州玉龙蕨自然居群5个样地的调查统计,分析了其群落特点、区系特征、生态位宽度与生态位重叠值.结果表明:(1)玉龙蕨有4种生活群落类型;(2)群落植物资源相对稀少,共有维管束植物34科53属62种;(3)群落种子植物区系构成以温带分布属为主,占总属数的78.43%;(4)玉龙蕨生态位宽度相对适中,与珠芽蓼的生态位重叠值最大.     

假冷蕨属叶表皮特征的比较形态学研究

利用光学显微镜对假冷蕨属植物叶表皮特征进行观察,并与亲缘关系较近的冷蕨属、蹄盖蕨属植物进行比较.结果显示:假冷蕨属和蹄盖蕨属植物上表皮细胞的垂周壁都有加厚,且多为波浪状;下表皮细胞的气孔密度和气孔器类型也很接近.结合分子系统学的相关结论,我们建议把假冷蕨属归并到蹄盖蕨属中.     

浙江省蹄盖蕨科植物地理分析

浙江省蹄盖蕨科植物有14属、59种,半数以上的种属于短肠蕨属或蹄盖蕨属,单种属比例明显偏高.浙江省蹄盖蕨科植物分布广泛,从属和种的数量来看西部、西南部和南部地区多于中部、北部和东部地区.浙江省单种属中除安蕨属在省内山地丘陵均有分布外,其余6属分布范围很狭小,只分布在浙西、浙西南和浙南地区.蹄盖蕨科植物在海拔400～900m之间物种最多.     

云南莲座蕨科植物叶表皮形态特征研究

 通过在光镜下对云南境内12种莲座蕨科植物的叶表皮细胞进行观察研究,发现:①气孔类型可作为莲座蕨属和原始莲座蕨属分类依据;②气孔密度可作为分种依据.叶表皮细胞结构特征具有重要的分类学及系统学意义,其中莲座蕨科12种植物的气孔器密度、11种植物叶表皮细胞结构解剖照片均属首次报道.     

种子植物系统分类提纲

种子植物的胚珠分别来自无孢子叶的顶枝及孕性的孢子叶,并形成了五种不同类型的种子和果实,即银杏型,科达狄一本内苏铁型,紫杉型,苏铁一有花植物型,松柏型.银杏、苏铁、紫杉及罗汉松的成熟的受精胚囊不是简单的种子.银杏的珠领,紫杉及罗汉松的肉质杯状体是和有花植物的心皮等价的有效保护组织,它们是在系统发育早期,在起源上与有花植物的保护组织有截然不同来源,它们是雏型的果实或原始型的果实.买麻藤类是众所周知的盖子植物,它具有双受精,而且不具颈卵器,只有松柏类才是真正的裸子植物.本文不采用传统的种子植物分类法,而把种子植物,包括已知的种子蕨在内,分为下列十个亚门,它们是种子蕨亚门、舌蕨亚门、松柏亚门、银杏亚门、苏铁亚门、开通亚门、中华缘蕨亚门、紫杉亚门、盖子亚门、有花植物亚门.在最后的有花植物亚门,也提出了一个新的系统.     

泥盆纪枝蕨纲的分支系统学研究

枝蕨纲是中泥盆世至早石炭世的一个重要的植物类群。作者对枝蕨纲代表植物进行了尝试性的分支系统学研究。枝蕨纲中可识别出伊瑞蕨目、瘤指蕨目和其他一些过渡类型。伊瑞蕨目和瘤指蕨目演化关系密切,二者分别以营养性末级附枝的顶端回弯和具瘤指蕨型的植物体组构为近裔共性。中国中上泥盆统的Metacladophyton和Polypetalophyton比伊瑞蕨目和瘤指蕨目进化程度要高,可能代表枝蕨纲内的一个新的高级分类单元,以具片化的末级附枝及次生生长为特征。伊瑞蕨目和瘤指蕨目出现在中泥盆世,而以Metacladophyton和Polypetalophyton为代表的进化类型出现在中泥盆世晚期至晚泥盆世早期。从伊瑞蕨目、瘤指蕨目到Metacladophyton和Polypetalophyton,侧生分枝系统显示了从三维的枝系统向似羽片状系统逐渐演化的趋势。     

山东淄博煤田晚石炭世——早二叠世植物群落特征

山东淄博煤田晚石炭世—早二叠世植物化石经鉴定,共计37属104种,其中包括11个新种。分析了本区植物化石的埋藏类型,根据各类植物的生活习性和生境,将晚石炭世—早二叠世植物群划分为五个植物群落,讨论了它们的多度、成分、结构和生活型等特征,并采用信息函数数理统计方法,应用电子计算机对各植物群落的分异度和均衡度进行了计算。     

Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era

The widespread appearance of megaphyll leaves, with their branched veins and planate form, did not occur until the close of the Devonian period at about 360 Myr ago. This happened about 40 Myr after simple leafless vascular plants first colonized the land in the Late Silurian/Early Devonian, but the reason for the slow emergence of this common feature of present-day plants is presently unresolved. Here we show, in a series of quantitative analyses using fossil leaf characters and biophysical principles, that the delay was causally linked with a 90% drop in atmospheric pCO2 during the Late Palaeozoic era. In contrast to simulations for a typical Early Devonian land plant, possessing few stomata on leafless stems, those for a planate leaf with the same stomatal characteristics indicate that it would have suffered lethal overheating, because of greater interception of solar energy and low transpiration. When planate leaves first appeared in the Late Devonian and subsequently diversified in the Carboniferous period, they possessed substantially higher stomatal densities. This observation is consistent with the effects of the pCO2 on stomatal development and suggests that the evolution of planate leaves could only have occurred after an increase in stomatal density, allowing higher transpiration rates that were sufficient to maintain cool and viable leaf temperatures.     

A complete insect from the Late Devonian period

After terrestrialization, the diversification of arthropods and vertebrates is thought to have occurred in two distinct phases, the first between the Silurian and the Frasnian stages (Late Devonian period) (425-385?million years (Myr) ago), and the second characterized by the emergence of numerous new major taxa, during the Late Carboniferous period (after 345?Myr ago). These two diversification periods bracket the depauperate vertebrate Romer's gap (360-345?Myr ago) and arthropod gap (385-325?Myr ago), which could be due to preservational artefact. Although a recent molecular dating has given an age of 390?Myr for the Holometabola, the record of hexapods during the Early-Middle Devonian (411.5-391?Myr ago, Pragian to Givetian stages) is exceptionally sparse and based on fragmentary remains, which hinders the timing of this diversification. Indeed, although Devonian Archaeognatha are problematic, the Pragian of Scotland has given some Collembola and the incomplete insect Rhyniognatha, with its diagnostic dicondylic, metapterygotan mandibles. The oldest, definitively winged insects are from the Serpukhovian stage (latest Early Carboniferous period). Here we report the first complete Late Devonian insect, which was probably a terrestrial species. Its 'orthopteroid' mandibles are of an omnivorous type, clearly not modified for a solely carnivorous diet. This discovery narrows the 45-Myr gap in the fossil record of Hexapoda, and demonstrates further a first Devonian phase of diversification for the Hexapoda, as in vertebrates, and suggests that the Pterygota diversified before and during Romer's gap.     

淮北煤田早二叠世植物群落及其组合特征

本文详细研究了淮北煤田早二叠世地层植物化石1300余块,其分属于10大类共69属165种。该区早二叠世植物化石丰富,保存良好,是典型的华夏植物群。根据该期植物群的纵向发育规律和空间分布特点,其可划分为两个植物组合,即早二叠世早期山西组的Cathaysiopteris whitei-Callipteridium koraiense-Cordaites schenkii组合带和早二叠世晚期下石盒子组的Lobatannularia ensifolia-Gigantonoclea spp.-Caulopteris spp.组合带。     

An early tetrapod from 'Romer's Gap'

The fossil record of early tetrapods has been increased recently by new finds from the Devonian period and mid-late Early Carboniferous period. Despite this, understanding of tetrapod evolution has been hampered by a 20-million-year gap ('Romer's Gap') that covers the crucial, early period when many key features of terrestrial tetrapods were acquired. Here I describe the only articulated skeleton of a tetrapod, Pederpes, yet found from the Tournaisian epoch (354-344 million years ago (Myr)). The new taxon includes a pes with five robust digits, but a very small, possibly supernumerary digit preserved on the manus suggests the presence of polydactyly. Polydactylous early tetrapods may have survived beyond the end of the Devonian and pentadactyly cannot be assumed for the pes. However, the pes has characteristics that distinguish it from the paddle-like feet of the Devonian forms and resembles the feet of later, more terrestrially adapted Carboniferous forms. Pederpes is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and was at least functionally pentadactyl. With its later American sister-genus, Whatcheeria, it represents the next most primitive tetrapod clade after those of the Late Devonian, bridging the temporal, morphological and phylogenetic gaps that have hitherto separated Late Devonian and mid-Carboniferous tetrapod faunas.     

Discovery of Cathaysiodendron Lee from the Early Carboniferous of Jingyuan, Gansu, western China

As one of the representative members of the Late Palaeozoic Cathaysian flora, Cathaysiodendron has been previously recorded from the Early Permian Taiyuan and Shanxi Formations in north China. The species of Cathaysiodendron presented here are from the lower member of Chouniugou Formation of Ciyao, Jingyuan, Gansu. The overlying marine beds yield fusulinids that are of Visean age in western Europe and conodonts of the Datang Stage in south China, so that the age of the bed containing Cathaysiodendron as Visean, Early Carboniferous, is well constrained. Such a record of Cathaysiodendron is significant in terms of Carboniferous phytogeography and the evolution of the Cathaysian Lepidophytes. A new species, Cathaysiodendron jingyuanense Wang & Wu sp. nov. is described and a second one mentioned.     

Noeggerathiales as coal-forming plants in Cathaysia: conclusions from an Early Permian vegetational Pompeii in Inner Mongolia

Noeggerathiales are an extinct group of sporebearing plants of uncertain systematic position that are known from Carboniferous and Permian age Euramerican and Cathaysian floras that occurred in presentday Europe, North America, and East Asia. The order Noeggerathiales includes over 50 species of more than 20 fossil genera, but their paleoecology is not well understood yet. Previously this group had been found only in extrabasinal floras or those inhabiting clastic wetlands. Noeggerathiales have never been recorded in coal ball floras. Thus, it is up to now uncertain whether this group has contributed to the formation of coal. Recent investigations of an Early Permian peatforming flora of the Taiyuan Formation near Wuda, Inner Mongolia, which was preserved in a volcanic ash fall has provided evidence that noeggerathialean plants not only existed in the peatforming vegetation but could even be the dominant group in some areas of the coal swamp. The Noeggerathiales in this particular peatforming forest include Tingia unita, Paratingia wudensis, and a new species of Paratingia. Exceptionally well-preserved specimens indicate that these noeggerathialean plants are small trees with a canopy of compound leaves and strobili near the top of an unbranched （monocaulous） stem.     

When horsetails became giants

Horsetails arose in the Late Devonian,evolved a greater diversity and forming fast growing bamboo-like thickets in the Carboniferous lowland swamp forest ecosystems.However,the diversity of this group drastically declined during the Permian while the climate became more dynamic and arid.Today only a single surviving genus exists,the herbaceous Equisetum.Here we report an exceptional large horsetail tree from the Early Permian Petrified Forest of Chemnitz.This fossil horsetail tree is assigned to Arthropitys bistriata (Cotta) Goeppert.It is 15 m high and over 25 cm in diameter,with thick wood and at least 3 orders of woody branching system formed a big canopy,and is morphologically very comparable with the living woody higher plants.This suggests that the plasticity mechanism of Permian calamitaleans enabled novel growth strategies when they competed with the rising gymnosperms during the environmental changes.     

The oldest articulated chondrichthyan from the Early Devonian period

Chondrichthyans (including living sharks, skates, rays and chimaeras) have a fossil record of scales and dermal denticles perhaps dating back to the Late Ordovician period, about 455 million years ago. Their fossil tooth record extends to the earliest Devonian period, almost 418 million years ago, whereas the oldest known articulated shark remains date from the Early Devonian period, about 394 million years ago. Here we report the discovery of an articulated shark that is almost 409 million years old from the Early Devonian (early Emsian) period of New Brunswick, Canada. The specimen, identified as Doliodus problematicus (Woodward), sheds light on the earliest chondrichthyans and their interrelationships with basal jawed vertebrates. This species has been truly problematic. Previously known only from isolated teeth, it has been identified as an acanthodian and a chondrichthyan. This specimen is the oldest shark showing the tooth families in situ, and preserves one of the oldest chondrichthyan braincases. More notably, it shows the presence of paired pectoral fin-spines, previously unknown in cartilaginous fishes.