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1.
2.
A new taxon of ginkgophyte affinity Palaeoginkgoxylon zhoui gen. nov. et sp. nov. is described from the Guadalupian Lower Shihhotse Formation of the Hulstai coalfield, Inner Mongolia Autonomous Region (Nei Mongol), northern China, on the basis of the anatomical structures of the broad eustele and pycnoxylic secondary xylem. The anatomical structure of the new woody tree trunk resembles both the early gymnosperms of Eristophyton-Pitus types and the modern Ginkgo. Therefore, the new tree trunk is interpreted as representing a transitional stage in the evolution of Ginkgo from early arborescent lignophytes since the Early Carboniferous.  相似文献   

3.
The stem anatomy and internal organisation of a newly collected sphenophyte trunk is studied from the type locality of Arthropitys, the Lower Permian petrified forest of Chemnitz, Germany. The trunk was found nearly in situ, still standing upright, and embedded in coarse-grained pyroclastics of the Zeisigwald Tuff Horizon (Leukersdorf Formation, Erzgebirge Basin). This specimen – the basal portion of a huge woody tree measuring up to 60 cm in diameter – represents the largest anatomically preserved calamite trunk ever found. On the basis of current investigation the exceptional find has been attributed to Arthropitys ezonata Goeppert, which is more completely characterised and emended herein. This species is characterised by its rather homogeneous loose wood without clearly distinct interfascicular rays and fascicular wedges. For the first time we are able to show details of the primary body of this poorly understood species such as vascular strands and pith parenchyma. Comparisons are made with the generitype Arthropitys bistriata (Cotta) Goeppert and other species of the genus Arthropitys.  相似文献   

4.
山西柳林孙家沟组锯齿龙类新材料及其分类学意义(英文)   总被引:1,自引:0,他引:1  
记述了产自山西柳林县薛村镇附近上二叠统孙家沟组的锯齿龙类新材料,包括两个单独的上颌齿和一个保存有牙齿的不完整齿骨。这两颗上颌齿与柳林黄河龙(Huanghesaurus liulinensis)正型标本来自同一地点同一层位且大小相当,由于同一地点没发现过其他的锯齿龙类,推测它们是同种甚至可能是同一个体而且应归入黄河龙;然而在形态特征上这两颗牙齿与矮小三川龙(Sanchuansaurus pygmaeus)正型标本上的牙齿完全相同,可以归入三川龙。新发现的齿骨与矮小三川龙和薛村山西龙(Shansisaurus xuecunensis)正型标本产自同一地点,层位与三川龙相同,低于山西龙的层位,推测很可能也属于三川龙,但是也不排除属于山西龙的可能性;在形态特征上与黄河龙正型标本在齿骨及其下颌齿的形态特征上未见明显差异,可以归入黄河龙。由于柳林黄河龙与薛村山西龙头后骨骼特征也基本一致,认为柳林薛村仅有一个属种的锯齿龙,矮小三川龙和柳林黄河龙应为薛村山西龙的晚出同义名。  相似文献   

5.
Late Permian terrestrial faunas of South Africa and Russia are dominated taxonomically and ecologically by therapsid synapsids. On the basis of a single specimen from the Upper Permian of South Africa, the varanopseid Elliotsmithia longiceps is the sole basal synapsid ('pelycosaur') known from Gondwana. Recent fieldwork in the Upper Permian of South Africa has produced a second varanopseid specimen that is referrable to Elliotsmithia . Data from both this specimen and the holotype suggest that Elliotsmithia forms a clade with Mycterosaurus from the Lower Permian of North America and Mesenosaurus from the Upper Permian of Eastern Europe. That postulate is supported by the three most parsimonious trees discovered in a new analysis of varanopseid phylogeny. However, the available data cannot resolve the interrelationships of these three genera. The new phylogenetic results contrast with earlier work identifying Elliotsmithia as the basal member of a clade that includes the North American taxa Aerosaurus , Varanops , and Varanodon . The new trees reduce the stratigraphic debt required by the latter scenario, and the one with the least stratigraphic debt identifies Elliotsmithia and Mesenosaurus as sister taxa. Two new taxa are erected, Mycterosaurinae and Varanodontinae, for the two varanopseid subclades.  相似文献   

6.
A New Basal Lystrosaurid Dicynodont from the Upper Permian of South Africa   总被引:1,自引:0,他引:1  
A new genus and species of late Permian dicynodont, Kwazulusaurus shakai , is described on the basis of a complete skull from the late Permian Dicynodon Assemblage Zone of the South African Beaufort Group. It is an advanced form which shows characters, such as the shape of the snout and the loss of the ectopterygoid, that link it to the early Triassic genus Lystrosaurus. Kwazulusaurus represents the most basal member of the lystrosaurian lineage. The phylogeny of progressive pristerodontian dicynodonts is discussed. It appears possible that the Kannemeyeriiformes and Lystrosauridae do not form a monophylum, as previously assumed. Instead a sister-group relationship between lystrosaurids and dicynodontids plus kannemeyeriiforms is suggested.  相似文献   

7.
An anatomically preserved lycopsid, Lobodendron fanwanensegen. et sp. nov. Liu, Wang, Xue & Meng, is described from the Upper Devonian (Famennian) Wutong Formation of Changxing County, Zhejiang Province, China. The fossil plant bears slender, dichotomously branched axes. The vascular strand consists of solid terete primary xylem and lobed secondary xylem, which implies the result from the activity of possibly discontinuous cambium. The new plant has character combinations that do not conform to any branches in the canopy of the tree-lycopsids known previously, but resemble those of the basal part of some pseudoherbaceous lycopsids. This new plant may exemplify a Late Devonian lycopsid with a pseudoherbaceous growth habit.  相似文献   

8.
Two new genera (Sinosphaera and Trigonosphaera), including two new species and another left in open nomenclature, are described from the Changxingian (upper Permian) of southern Guangxi, southern China. They are characterized by a single spherical, subspherical or rounded triangular cortical shell composed of two spongy layers and the likely absence of both a medullary shell and internal spicule. They are tentatively grouped within the family Xiphostylidae Haeckel, 1881 and are considered as the most primitive representatives of this family.  相似文献   

9.
Gorochov AV 《ZooKeys》2011,(130):131-136
Alexarasniidaefam. n. and Alexarasnia rossicagen. et sp. n. are described from the Upper Permian of European Russia. Systematic position of this enigmatic family within the infraclass Polyneoptera is unclear.  相似文献   

10.
This paper deals with Neocalamites tubulatus nov. sp., an equisetophyte belonging to the Equisetaceae family. The material studied originates from the Upper Permian deposits of the northern part of European Russia. N. tubulatus nov. sp. is characterized by both sterile and fertile organs belonging to the same parent plant. It has long, flexible stems, rarely branched, with alternating nodes and prolonged ribs on the stem surface corresponding to vascular strands of the stem, and compact lateral strobili, in general aspect similar to the strobili of extant species of Equisetum. N. tubulatus nov. sp. is one of the most ancient representatives of the Equisetaceae family, which shows a distinct morphological pattern of features, among which the lateral position of strobili, characteristic of primitive equisetophytes, is most prominent in this phase of their evolution.  相似文献   

11.
A study of both silicified and nonsilicified specimens of Permian reticularioid brachiopods from South China suggests thatPermophricodothyris, a genus previously rarely reported from China, is actually very common and abundant in the Middle and especially Upper Permian of South China. This study also clarifies, for the first time, that many of the reticularioid brachiopod species previously described asSquamularia in fact belong toPermophricodothyris. The new data presented in this paper also allows a critical evaluation ofPermophricodothyris in relation to its closest allies:Phricodothyris, Squamularia, Bullarina andNeophricodothyris. The revision reveals that a total of 18Permophricodothyris species are present in the Middle and Upper Permian of South China, with only one species,P. squamularioides, having survived the Permian-Triassic mass extinction. Two species,P. grandis (Chao) andP. guangxiensis Han, Zhou & Wang, are redescribed here, providing critical new information on the morphology and taxonomy of these species.  相似文献   

12.
Patranomodon nyaphulii , known from a nearly complete skull, lower jaw and partial postcranial skeleton, is morphologically the most primitive anomodont therapsid yet discovered. It is from the Eodicynodon Assemblage Zone, the lowest biozone of the Beaufort Group of South Africa, which has a primitive therapsid fauna comparable with that of the Russian Zone I. Patranaomodon is primitive with respect to other anomodonts in having short palatal exposure of the premaxilla, an unreduced tabular, a slit-like interpterygoidal vacuity, a screw-shaped jaw articulation (which precludes fore-aft sliding of the lower jaw), and only three sacral vertebrae. The poorly-known Galechirus and Galepus from the younger Cistecephalus Assemblage Zone appear to be at a comparably primitive evolutionary grade, and the three genera are tentatively united in the family Galechiridae. The taxon Dromasauria is shown to be paraphyletic and therefore should be discarded.  相似文献   

13.
The wood of theSarraceniaceae has a considerable number of primitive features including scalariform perforation plates, long and oblique end walls, scalariform lateral wall pitting, solitary vessels, tracheids with scalariform pitting, and diffuse axial parenchyma. Vessel elements in the genusHeliamphora have the greatest number of primitive features, while vessel elements inDarlingtonia andSarracenia appear to have modifications relating to temperate climates. The wood anatomy suggests thatHeliamphora is growing in a habitat more similar to the original habitat for the family thanDarlingtonia andSarracenia. The wood of theSarraceniaceae is similar to the wood of theTheales.  相似文献   

14.
A new dicynodont genus and species, Idelesaurus tataricus sp. nov. (Cryptodontidae), from the Semin Ovrag locality (Tatarstan, Tetyushinskii District; Upper Permian, Upper Tatarian Substage, Severodvinian Horizon) is described. The skull patterns of the East European and South African Cryptodontidae and Aulocephalodontidae are compared from the morphofunctional point of view.  相似文献   

15.
Summary The roles of Permian colonial corals in forming organic reefs have not been adequately assessed, although they are common fossils in the Permian strata. It is now known that colonial corals were important contributors to reef framework during the middle and late Permian such as those in South China, northeast Japan, Oman and Thailand. A coral reef occurs in Kanjia-ping, Cili County, Hunan, South China. It is formed by erect and unscathed colonies ofWaagenophyllum growing on top of one anotherin situ to form a baffle and framework. Paleontological data of the Cili coral reef indicates a middle to late Changhsing age (Late Permian), corresponding to thePalaeofusulina zone. The coral reef exposure extends along the inner platform margin striking in E-S direction for nearly 4 km laterally and generally 35 to 57 m thick. The Cili coral reef exhibits a lateral differentiation into three main reef facies; reef core facies, fore-reef facies, and marginal slope facies. The major reef-core facies is well exposed in Shenxian-wan and Guanyin-an sections where it rests on the marginal slope facies. Colonial corals are dispersed and preserved in non-living position easward. Sponges become major stabilizing organisms in the eastern part of Changhsing limestone outcrop in Kanjia-ping, but no read sponge reefs were formed. Coral reefs at Cili County in Human are different distinctly from calcisponge reefs in South China in their palaeogeography, lithofacies development, organic constitutuents, palaeoecology and diagenesis. The Cili coral reef also shows differences in age, depositional facies association, reef organisms and diagenesis from coral reefs in South Kitakami of Japan, Khorat Plateau of Thailand, and Saih Hatat of Oman. Although some sponge reefs and mounds can reach up to the unconformable Permian/Triassic boundary, coral reef at Kanjia-ping, Cili County, is the latest Permian reef known. This reef appears to had been formed in a palaeoenvironment that is different from that of the sponge reefs and provides an example of new and unique Permian reef type in South China, and could help us to: 1) understand the significance of colonial corals in Permian carbonate buildups; 2) evaluate the importance of coral community evolution prior to the collapse of reef ecosystems at the Permian/Triassic boundary; 3) better understand the effects of the biotic extinction events in Palaeotethys realm; 4) look for environmental factors that may have controlled reefs through time and space, and 5) provide valuable data for the study of Permian palaeoclimate and global evolutionary changes of Permian reefs and reef community.  相似文献   

16.
Our understanding of the glossopterid gymnosperms from the Permian of Gondwana has recently been greatly enhanced through the study of anatomically preserved plant remains in cherts from several localities in Australia and Antarctica. Studies ofGlossopteris leaves, leaf-stem attachment, stem structure and wood anatomy,Vertebraria roots, ovule- and pollen-bearing reproductive structures and putative glossopterid pollen and ovules demonstrate that the glossopterids were a diverse group of sophisticated gymnosperms. Comparative studies of different Permian chert floras show that while some glossopterid elements are widespread, other taxa appear to be more localized in their distribution. As information from petrified plant-bearing cherts becomes available, it can be used to reconstruct whole glossopterid plants and establish their paleogeographic distribution.  相似文献   

17.
华西南毛茛科六新种和二新变种   总被引:1,自引:0,他引:1  
王文采 《广西植物》2013,(5):579-587
该文描述了自华西南东部发现的毛茛科翠雀属2新种和1新变种、唐松草属1新种、银莲花属1新种和1新变种,以及毛茛属2新种。  相似文献   

18.
The skull of a small anomodont therapsid, from the Tapinocephalus Assemblage Zone (Abrahamskraal Formation, Beaufort Group, Upper Permian) in Northern Cape Province, South Africa, represents a new basal dicynodont and is described in detail. Colobodectes cluveri gen. et sp. nov. is distinguished from other dicynodonts by an anteroposteriorly extensive caniniform process, parietals that were broadly overlapped posterolaterally by posterodorsal processes of the postorbitals, diverging anterior palatal ridges, and a dorsoventrally low foramen magnum. A phylogenetic analysis indicates that Colobodectes is the basalmost member of a dicynodont clade that excludes Eodicynodon . This position is not particularly strong, as two additional steps are needed to make Colobodectes and Eodicynodon oosthuizeni exchange places on the most parsimonious tree. Another discovery of the phylogenetic analysis is that there is little basis for recognizing Eodicynodon oelofseni as the closest relative of E. oosthuizeni . The former species is identified as the sister taxon of a clade that includes the latter and all other dicynodonts.  相似文献   

19.
Exceptionally well-preserved specimens of Mizzia yabei (Karpinsky) were discovered in bituminous packstone intercalations of the early Upper Permian Maokou Formation of Anxian County (Sichuan, China). Staining techniques and x-ray diffraction reveal that the organic encrustation around the central stem and the lateral branches consists of aragonite. Average aragonite contents range between 27% and 40%. The bulk of the remaining 60–73% calcite represents cement. The total Sr-content is 3, 400 ppm, indicating 8,000–10,000 ppm for the aragonite fraction. The organically precipitated aragonite was deposited as closely packed fibres, 10–20 μm long and 0.5–1 μm wide. The fibres are arranged in clinogonal (water-jet) fascicles, which diverge towards the central (spar-filled) stem. This microstructure shows that the mineralization of the mucilage started at the periphery of the extracellular encrustation and progressed toward its interior. Diagenetic alterations of the original aragonite include various stages of breakdown of the fibres into 0.5–1 μm large granules (micritization), minor syntaxial growth of the fibres and local transformation of acicular aragonite into neomorphic calcite. The dasycladaleans from the Permian of Sichuan appear to be by far the oldest representatives of this order with preserved aragonitic mineralogy and microstructure. Comparably well-preserved examples are only known from Eocene and younger deposits.  相似文献   

20.
Summary The structure and anatomy of mature flowers of four species of Meliosma is investigated using scanning electron and light microscopy. The vasculature of the flower, including the structure of the gynoecium, is described in detail. The mechanism of stamen maturation and pollen release is illustrated and discussed. The existence of an explosive pollination mechanism is questioned for at least part of the species. Flowers are proterandrous and fertile stamens are kept spatially separate from the style by a ring of large staminodes. Anthers are disporangiate by the loss of the adaxial pollen sacs. During maturation the filament bends progressively outwards and releases the pollen on the extension of the connective that acts as a secondary pollen presentation system. The nectary has five appendages topped with stomata secreting abundant nectar. The relationships of Sabiaceae are discussed relative to other early diverging eudicots. The significance of Sabiaceae as an isolated clade is highlighted, although some features point to a link with Menispermaceae.  相似文献   

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