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1.
GIgantonoclea: an enigmatic Permian plant from North China   总被引:1,自引:0,他引:1  
Gigantonoclea is a distinctive and enigmatic plant from the Permian of North China proper, with an unusual frond architecture and a pollen organ and vascular structure which are unique; it demonstrates a sudden rise and a rapid extinction. This paper reviews previous work on Asian gigantopterids and describes new material from the Upper Permian of Shanxi Province, including a new type of pollen organ (Jiaochengia lagrelii) and two new species of frond (Gigantonoclea crenataG. pubescens). Jiaochengia shows opposite, dissected and rather modified microsporophylls, laxly aggregating into an independent organ, which is markedly different from ‘Gigantotheca’ from Fujian. This presents evidence of heterogeneity among Asian gigantopterids and partly supports a relationship with the Carboniferous Callistophytales. Jiaochengia sporangia have what may be the first record of a waxy covering on the outer surface of a fossil plant, which is interpreted to have functioned to repel water, to protect against fungal attack and to scatter light. According to Hickey's rule, the venation of true Gigantonoclea fronds consists of three orders of main veins (rachis, midvein and secondary veins) and two orders of anastomosing veins (tertiary veins and veinlets). Certain putative ‘Gigantonoclea’ species from South China and some peripheral areas of North China do not have this type of venation and are thus excluded from the genus. Frond dimorphism is common among gigantopterids in both North and South China and can be compared with the amphibious variation from submerged to emergent leaves in extant aquatic plants. G. pubescens has a thick, bi-layered adaxial cuticle with an indumentum covering with dense papillae and trichomes bases, and deeply sunken, papillate stomata, suggesting that it favoured more arid conditions. An observed gradient from pubescent to glabrate or even glabrous gigantopterid cuticle structures between North and South China suggests a change from xeric, mesic to humid habitats.  相似文献   

2.
大羽羊齿植物是一个令人迷惑的类群,这类植物中,Gigantonoclea,Zeilleropteris和Cathaysiopteris是北美和东亚二叠纪植物群共有的3个属,但美国最早发现的大羽羊齿植物Gigantopteridium以前在中国的大羽羊齿植物群中未有确切记录,文中订正和详细描述Gigantopteridium的一个中国种,并对该属中国种的一些相关问题作详尽的讨论,美国大羽羊齿类植物采用小泉源一(Koidzumi,1936),的分类系统,只依据叶脉特征进行分类,它是一人为分类系统(Mamay et al.,1988),根据这一系统,文中涉及的中国和美国标本都应归入Gigantopteridium这一属内,这样,东亚和北美大羽羊齿植物群中的大羽羊齿类植物共同属的数目就由3个增加到4个,在对Gigantopteridium huapingense(Feng)详细描述和订正的基础上,对Gigantopteridium中国种与美国种在叶结构方面的异同进行较为详细的比较,虽然此属目前尚未发现过生殖器官和保存解剖结构的材料。  相似文献   

3.
王永  何顺志 《广西植物》2015,35(4):476-486
采用制作叶脉标本和透明叶标本的方法,对贵州产28种2变种小檗属植物叶脉特征进行比较研究。结果表明:贵州小檗属植物的脉序类型有5种:半达缘羽状脉、花环状半达缘羽状脉、简单弓形羽状脉、花环状弓形羽状脉和混合型。叶脉分支一般有五级:1一级脉构架均为羽状脉,粗度有很粗、粗、中等粗细和纤细四种类型,分支方式包括单轴分支和合轴分支;2粗二级脉构架中有分支达缘或分支均不达缘,与中脉夹角变化各异,内二级脉存在或缺失,细二级脉半达缘、真曲行或简单弓形,间二级脉类型复杂多变但频度种间有差异;3三级脉贯串型、结网型或分支型;4四、五级脉网状或自由分支且常混合在一起。脉间区从发育差到良好,小脉从不分支到不均等分支等各种类型均有,叶缘末级脉缺失、不完整、钉状和环状。大部分种类叶缘具齿,每1cm齿数目和齿内腺点的特性等特征在不同种类间有区别,具有鉴定价值,但齿其它特征复杂多变或种间区别较小,同时齿内脉性状也不稳定。此外,齿的有无会对脉序类型产生影响。小檗属植物叶脉类型存在种间差异,具有重要的分类学价值,叶脉类型的变化和复杂程度显示了该属植物的进化特点;叶齿的有无和齿特征具有分类学和系统学意义。基于叶脉特征的研究结果并结合重要的外部形态学特征编制了贵州小檗属植物的分种检索表。研究结果可为小檗属植物分类寻找新的依据并探讨其系统学意义。  相似文献   

4.
Leaflets of Marsileaceae are described from the Albian (Early Cretaceous) strata of Jordan. The fossils are from the Jarash Formation (Kurnub Group) and are found in fluvial sediments along with water lily leaves. The small wedge-shaped leaves have dichotomous veins that anastomose and form a marginal vein. Based on comparisons to living genera, Marsileaceaephyllum mahisensis Hu, Taylor, Brenner et Basha, n. sp., is most similar to Marsilea, in particular, with terrestrial leaflet forms; yet, it is distinct from living and fossil species by its small size and the few dichotomously branched middle veins that have a monopodial course. In addition, a single similar-veined smaller leaf with a retuse apex is thought to be a juvenile leaf of the same species. This is the first megafossil evidence of the family from Africa/Arabian Peninsula.  相似文献   

5.
Delnortea is a monotypic genus (type-species: D. abbottiae) of Lower Permian gymnosperms based on leaves from uppermost Leonardian deltaic sediments exposed in the Del Norte Mountains, West Texas. The leaves are simple, symmetrical, mostly oblong or elliptical, and vary in length from 1.2 to about 35 cm. The petioles are short and stout, with a basally enlarged abscission zone. The margins are crenate, with a narrow, indurated border. Venation is in 4 orders: the secondaries and tertiaries are robust, unbranched, and pinnately arranged in a precise “herringbone” pattern, with the secondaries ending in the marginal sinuses; the quaternaries divide sparingly and fuse with others to form a dense reticulum of small meshes. Permineralized petiole and midrib material reflects a bifacial cambium, shown by a semicircular vascular arc, irregularly divided into several collateral bundles with secondary xylem and phloem. Delnortea is referable to the Gigantopteridaceae, a probably artificial family of gymnosperms incertae sedis with important venation features in common, but without known diagnostic reproductive organs. With Delnortea, the North American gigantopterids now include 5 genera, but Gigantopteris itself is lacking. Delnortea holds a relatively advanced evolutionary position among the American gigantopterids; its leaf morphology and gymnospermous anatomy entail intriguing points of comparison with Gnetum. The limited geographic and stratigraphic ranges and morphological distinctiveness of the American gigantopterids and associated taxa attest to rapid evolution and dispersal from a small area of origin in the southwestern United States during Leonardian time.  相似文献   

6.
Evolsonia is a new gigantopterid genus (type-species: E. texana), based on leaf impressions from 3 widely separated localities in north-central Texas. The leaves are associated with terrestrial vertebrates in floodplain sediments of the Vale Formation in the Clear Fork Group, of late Leonardian (Early Permian) age. Evolsonia leaves are simple, with very large elliptic laminae reaching 27 cm in width and 80 cm, possibly more, in length. Leaf margins are sinuate to crenate, with mostly shallow concavities. Venation is pinnate, in 4 orders; all but the ultimate veins are very thick and protrude below the lamina, creating deep impressions in the matrix. The secondary and tertiary veins form a precise herringbone pattern, with the secondaries and exmedial tertiaries ending at the leaf margin between concavities. The other tertiary veins are either simple or divided into 2 nearly equal divisions; they produce simple or variously divided quaternary veins that end at a thin sutural vein, forming a dense reticulum; some of the terminally branched tertiaries delimit areolelike areas that enclose several quaternaries and meshes. One of 6 presently known American gigantopterids, Evolsonia most closely resembles the younger Delnortea in gross architecture; with its sutures and dichotomously divided veins, however, Evolsonia is architecturally intermediate between Delnortea and the older American gigantopterids with forked leaves. Sedimentary features indicate deposition under alternating periods of flooding and drought. Their huge size invites comparison of Evolsonia leaves with those of modern tropical plants, whereas their thick veins and preservational features suggest thick, coriaceous texture.  相似文献   

7.
依据植物野外和腊叶标本形态观察以及小叶脉序观察,对贺兰山岩黄耆(豆科)及其近缘种进行了分类学研究。结果表明:贺兰山岩黄耆及其近缘种之间较为稳定的差别体现在花器官的形态方面。贺兰山岩黄耆与短翼岩黄耆的主要区别特征是小苞片长为萼筒的1~2倍,旗瓣与龙骨瓣近等长,而后者的小苞片长为萼筒的0.5~0.8倍,旗瓣长为龙骨瓣的0.8倍。贺兰山岩黄耆与华北岩黄耆和费尔干岩黄耆的主要区别是翼瓣长为龙骨瓣的0.3~0.5倍,而后二者的翼瓣长均为龙骨瓣的0.7~0.8倍。在小叶脉序特征方面,贺兰山岩黄耆与短翼岩黄耆和华北岩黄耆近似,均为小叶一级脉纤细,二级脉不分支,二级脉环外有较多网结三级脉,具少量复合二级间脉或不明显,而费尔干岩黄耆小叶一级脉粗,二级脉多分支,二级脉环外有少量网结三级脉,具明显的简单二级间脉。此外,小叶脉序特征可能在岩黄耆属组间关系的探讨中发挥作用。  相似文献   

8.
A comparative study was made of the gross morphology, fine venation and cuticular features of Leitneria fioridana Chapman, the single living representative of the order Leitneriales and Leitneria eocenica (Berry) Brown, presumbaly a related fossil species. In addition to the type material, newly collected fossil specimens were investigated from clay pits in the Middle Eocene, Claiborne Formation, of western Tennessee and Kentucky. Foliate stipules attached to the petioles of several specimens suggest the assignment of this fossil leaf type to the genus Leitneria is incorrect. The nature of the gross morphology, fine venation and cuticular features confirms the misidentification. Previously, various specimens of this fossil leaf type have been placed in eight species of seven genera in seven families of six angiosperm orders, none of which are correct systematically. The gross morphology, venation and cuticular characters of the fossil leaf are distributed among a few extant South American genera of arborescent Rubiaceae. The fossil is an extinct rubiaceous leaf type which cannot be placed within a single modern subfamily, tribe or genus of the family. The organ genus, Paleorubiaceophyllum is proposed for these leaves. Three varieties of a single fossil species, P. eocenicum, are recognized. One variety with epidermal cells nearly twice the size of the others may represent a polyploid population.  相似文献   

9.
A new syntonopterid, Anglolithoneura magnifica gen. et sp. n., is described from a siderite concretion (nodule) from the Late Carboniferous (Langsettian) of Lancashire County (UK). The new genus is diagnosed on hind wing venation and compared with other syntonopterid genera. The new species is the first syntonopterid formally described from the Late Carboniferous of Europe. The systematic positions of other potential Syntonopteroidea (Miracopteron mirabile, Bojophlebia prokopi, and specimens described in 1985 by J. Kukalová-Peck from Obora in the Czech Republic) are reconsidered. Wing venation synapomorphies are proposed for the Syntonopteroidea (sensu novo), and for a potential clade ((Ephemeroptera+Syntonopteroidea)+Odonatoptera) separated from the Palaeodictyopterida. The close relations of the new species with Lithoneura lameerei Carpenter, 1938 from Mazon Creek (Illinois, USA) provide additional support for a Euramerican connection during the Late Carboniferous.  相似文献   

10.
A new fossil genus and combination of gigantopterides is reported. The specimen was collected from the Late Paleozoic "Longtan Formation” of Jiangle county, Fujian Province of China. It was originally determined to the genus Gigantonoclea and named as G. cardiophylla Zhu et Geng by one of the present authors and his colleague some times ago. In view of its venation being trinervious and that the incompletely duplicated net-like veins are close to those of gigantopterides and the leaf bears sori on its back. Upon reconsideration it was renamed by the authors as Trinerviopteris cardiophyUa (Zhu et Geng) Zhu gen. et comb. nov. At the same time. the authors have confirmed that it is a kind of true fern. In association with the new taxon there are Sphenophyllum emarginatum, Bowmanites lascus, Lobatannularia lingulata, Chansitheca pcdaeosilvana, Ch. cf. kidstonii, Pecopteris anderssonii, P. echinata, P. taiyuanensis, P. unita, Danaeites mirabilis, Fascipteris densata, Cladophlebis permica, Compsopteris contracta, Gigantonoclea chingii, G. fukienensis, G. sp., G. sp., Gigantopteris cordata, G. nicotianaefolia, Taenioteris serrulata, T. szei, T. tingii, Radicites sp. 1, R. sp. 2 etc. The present flora is more simplified than the others which discovered from different areas in the same geological time. Based on the grouping of these fossil plants, the geological era of the present flora must be late Early Permian to early Late Permian. Moreover it is emphasized that the gigantopterides is only but an artificial compound taxon not only including seed ferns but also true ferns and others.  相似文献   

11.
The gigantopterids are a pan‐palaeotropical Late Palaeozoic (to Early Mesozoic) plant group with unknown affiliations. Two gigantopterid species, both sole representatives of their respective genera, are known from the Early Permian Mengkarang Formation of Jambi (Sumatra, Indonesia). Through an emendation of the Jambi gigantopterids, based on the old and newly collected material, and a subsequent analysis of the leaf morphology of several gigantopterid genera, we conclude that the Jambi species are similar to the other gigantopterids, but do not appear to be related to them directly. We propose a possible scenario for the evolution of gigantopterid leaf morphology, based on marginal leaf growth, with implications for the validity of the gigantopterids as a natural group. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 302–328.  相似文献   

12.
Abstract: Chondrichthyans are newly reported from the autochthonous Wordian Khuff Formation (middle Permian), cropping out in well‐exposed, low‐palaeolatitude sections in the interior Haushi‐Huqf area of Oman. The shark remains comprise isolated teeth, dermal denticles and fin spines and have been recovered by processing limestone in buffered acetic acid from bulk rock samples. The fauna consists of mainly ctenacanthiform and hybodontiform taxa, identified as Glikmanius cf. myachkovensis, Glikmanius culmenis sp. nov., Omanoselache hendersoni gen. et sp. nov., Omanoselache angiolinii gen. et sp. nov., cf. Omanoselache sp., Reesodus underwoodi gen et sp. nov., Teresodus amplexus gen. et sp. nov., Gunnellodus bellistriatus, Khuffia lenis gen. et sp. nov., Khuffia prolixa gen. et sp. nov. and Euselachii sp. indet. Additional specimens include rare teeth of the lonchidiid cf. ‘Palaeozoic Genus 1’ sp., of the neoselachian Cooleyella cf. fordi and a further indeterminate neoselachian, of an indeterminate petalodont and of the holocephalan Deltodus aff. mercurei and Solenodus cf. crenulatus. Fin spines add a further two taxa, Nemacanthus sp. and Amelacanthus cf. sulcatus, which have neoselachian affinities and therefore an unclear relationship to the recovered teeth. The occurrence of Nemacanthus within this Wordian fauna represents the oldest record of this taxon and its only known occurrence in the Palaeozoic. Of the remaining genera, Glikmanius has previously been recorded from the Wordian, whereas for all the others, this study represents their youngest known stratigraphic occurrence and first occurrence in Guadalupian (middle Permian) strata. This adds significantly to our knowledge of the global diversity of chondrichthyans preceding the end‐Guadalupian biotic crisis. Palaeogeographically, for all taxa, this study represents the first record from the western fringe of the marine Neotethyan basin, and only Cooleyella was previously known from the southern (Gondwanan) part of the Pangaean continental margin.  相似文献   

13.
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   

14.
分别基于波茎赤叉脉叶蝉Rakta sinuata sp. nov. 为模式种建立了赤叉脉叶蝉属Rakta gen. nov.,基于双突白叉脉叶蝉Albodikra bifida sp. nov. 为模式种建立了白叉脉叶蝉属Albodikra gen. nov.,进行了描记和绘图。虽然这两个属的后翅翅脉近似于小绿叶蝉族的特征,但此处将它们置于小叶蝉中的叉脉叶蝉族,并讨论了归族所依据的形态特征。  相似文献   

15.
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   

16.
Three new taxa from Albian, Early Cretaceous assemblages in Gondwana (Australia and Antarctica) and two previously described fossils from the Late Cretaceous and Eocene of North America are attributable to the heterosporous semi-aquatic fern family Marsileaceae. They are assigned to Marsileaceaephyllum, a morphotaxon erected here for sterile remains (whole plants, and isolated leaves and leaflets) of Marsileaceae. The Gondwanan taxa, Marsileaceaephyllum lobatum and Marsileaceaephyllum spp. B-C, have either a cruciform leaflet arrangement or dichotomous and anastomosing venation characteristic of modern Marsileaceae. Two previously established taxa, Marsilea johnhallii and Marsilea sp., which represent sterile Marsileaceae, are also transferred to the new genus (now Marsileaceaephyllum johnhallii and Marsileaceaephyllum sp. A, respectively). Examination of all fossil venation patterns reveals four new venation types not present in extant taxa, suggesting that most fossil Marsileaceae (leaves) are distinct from extant genera, and are likely members of extinct lineages. This is further supported by the absence of modern megaspore types in the Early Cretaceous.  相似文献   

17.
Two new fossil species, Archaeohelorus polyneurus sp. n. and A. tensus sp. n., assigned to the genus Archaeohelorus Shih, Feng & Ren, 2011 of Heloridae (Hymenoptera), are reported from the late Middle Jurassic, Jiulongshan Formation of Inner Mongolia, China. Based on the well-preserved forewings and hind wings of these specimens, the diagnosis of the Archaeohelorus is emended: forewing 2cu-a intersecting Cu and Rs+M at the same point or postfurcal, and hind wing may have tubular veins C, Sc+R, R, Rs, M+Cu, M and Cu distinct, or simplified venation. The new findings also elucidate the evolutionary trend of forewing and hind wing venation and body size for the Heloridae from the late Middle Jurassic to now.  相似文献   

18.
Foster , Adriance S. (U. California, Berkeley), and Howard J. Arnott . Morphology and dichotomous vasculature of the leaf of Kingdonia uniflora. Amer. Jour. Bot. 47 (8): 684–698. Illus. 1960.—An intensive study of the nodal anatomy, petiolar vasculature and open dichotomous venation of the leaf of Kingdonia has revealed a type of foliar vascular system of unusual morphological and phylogenetic interest. The vascular supply at the nodal level consists of 4 collateral traces which diverge from a single gap into the sheathing leaf base. This type of nodal anatomy is perhaps primitive, and comparisons are made with the unilacunar nodes and the 2- and 4-parted leaf trace systems characteristic of many angiospermous cotyledons and the foliage leaves of certain woody ranalian genera. The petiole of Kingdonia is vascularized by 2 pairs of bundles which represent the upward continuation of the 4 leaf traces. A transition from an even (4) to an odd (3) number of strands occurs near the point of attachment of the 5, lobed, cuneiform lamina segments to the petiole. Each of the 2 abaxial bundles dichotomizes and the central derivative branches fuse to form a double bundle which enters the base of the median lamina segment. The 2 adaxial petiolar bundles diverge right and left into the bases of the paired lateral segments of the lamina. An analogous type of transition from an even to an odd number of veins occurs in many angiospermous cotyledons which develop a definable mid-vein. But, in Kingdonia, the bundles which enter the bases of the lamina segments give rise to systems of dichotomizing veinlets devoid of “mid-veins.” Although the majority of the terminal veinlets enter the marginal teeth of the lamina segments, “blind” endings, unrelated to the dentations, occur in all the leaves studied. Typically, all of the vein endings in a given lobule of a lamina segment are derived from the same dichotomous vein system. However, in some leaves, a veinlet dichotomizes directly below a sinus and the branches diverge into the marginal regions of 2 separate lobules. The phylogenetic significance of the occurrence of open dichotomous venation in such an herbaceous angiosperm as Kingdonia is briefly discussed. From a purely morphological viewpoint, the Kingdonia type of venation invites direct comparison with the venation of Sphenophyllum, certain ferns or Ginkgo rather than with any of the known reticulate venation patterns of modern angiosperms. Although the foliar venation of Kingdonia may represent the result of evolutionary reversion, the very rare anastomoses which occur seem primitive in type rather than “vestiges” of a former system of closed venation.  相似文献   

19.
Leaf architectural pattern has been studied in 27 genera and 35 species of the Acanthaceae. The major venation pattern conforms to pinnate camptodromous with eucamptodromous or festooned brochidodromous secondaries, pinnate craspedodromous inAcanthus ilicifolius and acrodromous inLepidagathis trinervis. Intersecondary veins are common. The marginal ultimate venation is looped. The areoles are variable in size. The vein endings are usually simple, linear or cuved or divide once or twice dichotomously. Isolated vein endings, tracheids, isolated free vein endings and extension cells are observed. Transfusion tracheids are seen inDicliptera verticillata. Miniature vessel elements with simple perforation plates are noticed lying free in the areole or at the end of tracheids inSeriocalyx scaber andThunbergia grandiflora.Elytraria acaulis, Nelsonia canescens andStaurogynae zeylanica exhibit venation pattern shown by majority of the taxa studied, of the Acanthaceae.  相似文献   

20.
A new monotypical genus with a new species, Phormotegus lenociniosus gen. et sp. n., is described from Argentina. The new genus is closely related to the genera Taosa Distant and Brachytaosa Muir, but differs from them in the reticulate venation of the submacropterous fore wings with outcurved apices and in the unique position of the hind wings projecting laterally from the apices of the fore wings.  相似文献   

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