Late Silurian trilete spores from northern Jiangsu, China

The Late Silurian is generally considered to a particular significant key period in the study of early land vascular plants. A trilete spore assemblage of the Upper Silurian is described from northern Jiangsu, China. This assemblage comprises 11 genera and 20 species of trilete spores (including laevigate, apiculate, perinotrilite, patinate, rarely distally murornate and equatorially crassitate, and three indeterminate trilete miospores forms). It has similarities to those described from coeval assemblages from around the world (e.g., England and South Wales; Tripolitania, Libya; Cornwallis Island, Canadian Arctic; Northwest Spain). The rare cryptospore, only one specimen (Tetrahedraletes sp.) had been found to be associated with the Chinese trilete spore assemblage. The discovery of the trilete spores from Late Silurian rocks indicates the existence of early land plants, some possibly vascular, at that time in northern Jiangsu, China.     

An aquatic microfossil assemblage from Cenomanian amber of France

The ‘osseous’ amber from the Cenomanian of northwestern France contains numerous microscopic inclusions, some of which are fairly well preserved and identifiable as protists. This paper describes three cyanobacteria similar to modern Plectonema. Lyngbya, and Coelosphaeriunr, fungus-like fossils of uncertain affinities (cf. ?Candida); a colorless chrysomonad similar to Monas; a desmid identical with Closterium; and naked ciliates of uncertain affinities (cf. Cyrtolophosis). All of these fossils are in a single sample of amber from Bretagnolles (Eure Département). This assemblage is comparable to modern limnetic microbial communities. It is typical of shallow freshwater environments in which productivity and respiration are both high. This interpretation fits paleoecological reconstructions drawn from the arthropod fossils from French amber. ***Chrysomonads, ciliates, Cretaceous, cyanobacteria, desmids, fungi, micropaleontology.     

Morphologically complex plant macrofossils from the Late Silurian of Arctic Canada

In addition to vegetative remains, fertile remains from ten plants, representing seven distinct taxa whose size and complexity are much greater than most contemporaneous fossils, are reported from late Ludlow (Ludfordian) sediments of Bathurst Island in Nunavut, Canada. Evidence for the age of these beds is gathered from stratigraphic relationships and index fossils including conodonts, graptolites, and brachiopods. Zosterophylls dominate the collection, some of which constitute the earliest record of fertile structures arranged in dense clusters and longitudinal rows along axes. Representatives include a plant that resembles Bathurstia, one species of Zosterophyllum, and two specimens that bear affinity to this genus. Distichophytum is also represented, as is a new zosterophyll named Macivera gracilis. The prevalence of sporangial clustering and reduced sporangial stalks in this flora leads to a discussion of the origins and significance of these morphological features. Following a review of some of the other Silurian floras, particularly the Baragwanathia-bearing Lower Plant Assemblage of Victoria, Australia, which also shows morphological advancement over the rhyniophytoid-dominated floras common to Laurussia, it is concluded that the Bathurst Island flora presents the best evidence to date of substantial morphological diversity, complexity, and stature of vascular land plants in this period.     

Paleoenvironmental and paleobiogeographical implications of the microfossil assemblage from the Late Cretaceous intertrappean beds of the Manawar area,District Dhar,Madhya Pradesh,Central India

Abstract

An assemblage of microfossils consisting of non-marine ostracods (Cypridopsis, Gomphocythere, Zonocypris, Eucypris, and Frambocythere), charophyte gyrogonites (Platychara), molluscs (Viviparus, Valvata, and Lymnaea), and fish remains (mainly Phareodus), is here reported from a new intertrappean locality near the town of Manawar, District Dhar, Madhya Pradesh, Central India. The biotic component recovered suggests a Late Cretaceous (Maastrichtian) age for the intertrappean deposit near Manawar. Paleoenvironmentally, the overall biotic assemblage recovered indicates the presence of a freshwater palustrine/lacustrine depositional system connected to a low energy stream/river. Paleobiogeographically, the known high diversity of ostracod genera, especially Eucypris, Cypridopsis, and Gomphocythere, hints at endemism within the Indian Subcontinent during the Late Cretaceous (Maastrichtian). However, the cosmopolitan distribution of the charophyte genus Platychara in the K-Pg interval across the globe (Africa, Europe, and America) and its absence in the Upper Cretaceous of China and Mongolia is quite intriguing.     

Microfossil assemblage from the Late of Middle Carboniferous in Western Shaan-Gan-Ning Basin,Northwest China

In this paper, some results of the study on the sporepollen of the Yanghugou Formation in the western Shaan-Gan-Ning (Ordos) Basin of Northwest China axe reported. Plenty of well preserved microfossil, which 136 types belong to 62 microspore genera and one megaspore genus, including 2 new genera , 13 new species, I Acritarch (Chamosphaera pseudozonatus gen. et sp. nov.), from 8 bore-holes and outcrop have been discribed. In generally, the microfiora of the Yanghugou Formation is similar to the Taiyuan Formation (Upper Carboniferous). According to the spore-pollen assemblage of Yanghugou Formation may correlate with those in the Middle Carboniferous of Great Britain, Belgium the north of France, German and North America. Besides, the assemblage are similar to Middle Carboniferous of Nortth Shandong and Hengshanbu of Ningxia in the microfossil assemblage. The geological age of the beds is considered to Late of Middle Carboniferous.     

四川广元市现有的兽类动物

广元市辖 4县 3区 (青川、旺苍、剑阁、苍溪县 ,朝天、天坝、市中区 ) ,地处四川省北部盆周边缘 ,与陕、甘二省南部相邻。区内地貌为米仓山、龙门山、盆北低山及岷山、大巴山南部 5大单元的交汇地带 ,地质构造和褶皱强度是从北向南逐渐减弱 ,即由密集型过渡到宽缓型。地势形成西北高陡 ,青川县摩天岭大草坪为最高点海拔 3 82 7ｍ ,东南低缓 ,海拔多为 60 0～ 90 0ｍ ,苍溪县涧溪口最低海拔 3 52ｍ。总面积 1 63 2 8 5ｋｍ2 ,森林覆盖面积 985万亩 ,覆盖率达 3 8 1 %。境内有嘉陵江、白龙江、乔庄河、清江河、白水河、石门河、东河、南河、西…     

四川省广元市城郊的鸟类

1　自然概况广元市位于四川盆地北部周缘 ,东经 1 0 5°1 2′～1 0 6°1 7′ ,北纬 31°53′～ 32°52′。地势由北向南逐步降低 ,海拔多为 60 0～ 90 0ｍ ,以林、草覆盖为主 ,间有部分耕地的浅丘地带 ,市区内有嘉陵江及其支流南河、白龙江及清江河。市区北部属秦巴区北亚热带湿润季风气候。市区南部属四川盆地中亚热带湿润季风气候。区内四季分明 ,雨量充沛。 7、8月最高气温 38 6℃ ,1月份最低气温零下 5℃ ,年平均 1 6 1℃ ,无霜期 2 63天。降水主要集中在 6～ 9月份 ,年降雨量 972 6ｍｍ。2　自然环境与鸟类数量分布的历史变迁2 0世纪 …     

A Late Devonian plant assemblage from the Avon Gorge, west England: taxonomic, phylogenetic and stratigraphic implications

Plant fossils from the Avon Gorge originally identified as Rhacophyton sp. have been subjected to a detailed morphological study incorporating examination of both previously known material and new specimens. A single taxon, Chlidanophylon dublinensis, dominates the assemblage accounting for over 90% of the fossils encountered. Other plant organs identified include dispersed acupulate preovules and five less frequently occurring organs of which four are of unknown affinities; the leaf genus Platyphyllum, Alicomopleris sp., two kinds of novel and frequendy dichotomizing branching structures and the spermatophyte synangium Telangiopsis. Possible whole plant relationships between the components of the fossil assemblage are discussed and the stratigraphic, systematic and evolutionary position of the component taxa are considered.     

Late Silurian brachiopods from Darhan Mumingan Joint Banner, Inner Mongolia

Seven brachiopod species (including three new species) and three undetermined forms are described and figured here from an unnamed stratigraphic unit which mainly consists of argillaceous and bioclastic limestone near the stratotype of the Late Silurian Xibiehe Formation of the Xibiehe section in the Darhan Mumingan Joint Banner, north of the Bateaobao area, Inner Mongolia. Three new species, Eoschizophoria minuta, Navispira navicula and Howellella asiatica are established with transverse serial sections for their interiors. All brachiopod taxa described here show that this unnamed stratigraphic unit is higher than the Late Silurian Xibiehe Formation in the Xibiehe section and is possibly transitional between the Late Silurian and the Early Devonian. Authors temporarily regard this unit as the upper part of the Xibiehe Formation in this paper.     

A revision of xinjiangchelyid turtles from the Late Jurassic of Sichuan Basin,China

The type specimens of the Jurassic turtles from the Sichuan Basin (China) previously referred to plesiochelyid Plesiochelys are revised, which confirm that they belong to the family Xinjiangchelyidae. The study of a large number of additional shell material shows, as the dominant group, the Xinjiangchelyidae were greatly diversified in the Late Jurassic of the Sichuan Basin. By the absence of mesoplastron and other shell characters, Chengyuchelys baenoides is moved to Xinjiangchelyidae and considered as a valid taxon. Of the xinjiangchelyids from the Late Jurassic of Sichuan Basin, four genera are recognized: Chengyuchelys, Tienfuchelys, Yanduchelys and cf. Protoxinjiangchelys. The phylogenetic analysis results in that Chengyuchelys includes C. baenoides, C. latimarginalis and C. radiplicatus, and Tienfuchelys consists of T. tzuyangensis, T. chungkingensis and T. zigongensis. All xinjiangchelyids from the Sichuan Basin are more primitive than Xinjiangchelys in the plastron sutured to the carapace.     

Late Silurian trilobites from the Nuratau and Turkestan ranges, Uzbekistan and Tajikistan

Silurian trilobites of Ludlow and P?ídolí age are described from sections in southern Uzbekistan and from adjacent parts of Tajikistan. They belong to 22 species (10 named and 12 under open nomenclature) distributed among 13 genera belonging to the families Proetidae, Tropidocoryphidae, Aulacopleuridae, Scharyiidae, Cheiruridae, Encrinuridae and Odontopleuridae. The following new species are described: Interproetus pentaxus, Paleodechenella turkestanica, P. zaaminicus, Cromus tamchii and Leonaspis nuratensis. The generic associations from the mid Ludlow bear a striking resemblance to coeval ones from Bohemia, and include genera otherwise known only from that region or from adjacent parts of central Europe. The trilobite faunas from the late Ludlow and P?ídolí series are much less diverse and are dominated by genera of the Warburgellinae (Tropidocoryphidae), which include one species common to Vaigatch Island in the Russian Arctic, and Podolia, Ukraine. The closest links of the diverse central Asian mid Ludlow faunas are therefore to central Europe, whilst the sparser younger Ludlow and P?ídolí faunas, such as they are, suggest closer links to Baltica.     

Biogeographical analysis of Late Silurian brachiopod faunas, chiefly from Asia and Australia

Shallow water benthic marine invertebrates (such as brachiopods from Benthic Assemblages [BA] 1–3) have usually played a much more important role than deeper ones (BA 4–5 or even deeper) in evaluating biogeographical provincialism in geological history. The Silurian brachiopod Retziella Fauna, characterized by the common presence of Retziella in association with various provincial taxa and many common North Silurian Realm genera, is known from southwest Tienshan, North China, South China, North Vietnam, and East Australia. It is possibly also present in North Korea, the central Pamirs, Afghanistan, and New Zealand. The coeval Tuvaella Fauna occurs only in the southern marginal belt of the Siberian Plate. Synecologically, both faunas inhabited a normal, shallow-water, level-bottom environment, usually with a low-diversity community (commonly 3–8 genera); assignment to BA 2–3 is indicated. Their mutual exclusiveness is of biogeographical significance: subdivisions of the Uralian-Cordilleran Region can be based on them, with the Tuvaella Fauna being included in a redefined Mongolo-Okhotsk Province. A Sino-Australian Province is established and defined herein for the area occupied by the Retziella Fauna during the Ludlow-Pridoli and probably the Wenlock. Two subdivisions of the province can be recognized, a Sino-Central-Asian Subprovince and an Australian Subprovince, based on different endemic brachiopods and separate geographical positions. The presence of a number of more cosmopolitan genera in both the tropical-subtropical Sino-Australian and subtropical-temperate Mongolo-Okhotsk Provinces during the Late Silurian testifies to oceanic surface current circulation patterns adequate for the distribution of planktic larvae capable of long-distance dispersal while maintaining reproductive communication. This contrasts with the dispersal potential of endemic components of the newly defined Silurian biogeographical units. □ Late Silurian, Brachiopoda, Retziella , Fauna, Tuvaella Fauna, Synecology, Biogeography, Asia, Australia     

Late Ordovician-Early Silurian fluctuations in sea level from eastern Anticosti Island, Quebec

Over 1,000 m of Upper Ordovician to Lower Silurian mixed carbonate and clastic strata on Anticosti Island are nearly tectonically undisturbed, despite their proximity to the Northern Appalachians fronting Quebec's Gulf of St. Lawrence. Natural cliffs exposed along the coast and rivers in the eastern part of the island make a relatively conformable sequence belonging to the Ashgill and Llandovery Series. Fossil communities interpreted as depth-associated in life are especially repetitious in the Becscie, Gun River, Jupiter, and Chicotte Formations (Llandovery Series), and to a lesser degree in the Upper Vaureal and Ellis Bay Formations (Ashgill Series). Preliminary study of the pattern of changeovers in Eocoelia, Pentamerus and Stricklandia communities suggests that Anticosti seas deepened and shallowed three and a half times during the Early Silurian. High water peaks were reached during B₁-B₂, C₁-C₂ and C₄-C₅ times, with a final deepening trend beginning in late C₅ time. Age determinations of these events are based on the occurrence of graptolites (with some new records from Anticosti) keyed to the standard graptolite zones, and species of the Eocoelia lineage are also useful for correlation. The profile of the Anticosti sea-level curve compares well with other curves reconstructed from the Lower Silurian of New York, Michigan, and Iowa. Widespread synchronism in sea-level changes on the North American platform is thus corroborated.     

Implications of an early land plant spore assemblage for the late Silurian age of the Si Ka Formation,northern Vietnam

The first plant microfossil assemblage from the Si Ka Formation of the Song Cau Group, northern Vietnam is reported. It is composed of cryptospores in dyads and tetrads, trilete spores, tubular remains consisting of an association of smooth, banded, and externally thickened tubes, and cuticle-like fragments. The biostratigraphic assemblage of sporomorphs indicates a late Silurian (late Ludfordian) to Early Devonian (early Lochkovian) age. Further comparison with coeval reports using the characteristic features of the assemblage confines their age to the late Ludlow (late Ludfordian) to early Přídolí. This report presents the oldest spore assemblage from Vietnam and contributes to a broader understanding of its paleo-landscape during the late Silurian.     

Enigmatic occurrence of Permian plant roots in Lower Silurian rocks,Guizhou Province,China

Pinnatiramosus qianensis Geng, 1986, is a plant with a complex, extensive pinnate branching system and pitted tracheids, collected from marine Lower Silurian (Llandovery; c. 430 Ma) rocks in Guizhou Province, China. It challenges long‐held theories on the origin and early evolution of vascular plants in the Silurian and Devonian. However, there is a hypothesis that the fossils were not syngenetic with the entombing rock, but were the rooting systems of much younger plants, probably of Permian age. New sections and collections of P. qianensis have been subjected to detailed analyses, which indicate that P. qianensis belongs to an early Permian (c. 285 Ma) rooting system growing down into lower Silurian rocks.     

Hipparion material from Gaojiashan locality in the Late Miocene of Linxia Basin,Gansu, China and associated mammalian fossil assemblage

Two Hipparion species, H. forstenae and H. hippidiodus from Gaojiashan locality in the Linxia Basin, Gansu, China are described in this paper, with the first presence of the former in the Linxia Basin. The lower cheek teeth of Hipparion from Gaojiashan bear deep ectoflexids, and after comparisons to other Chinese Hipparion fossils with deep ectoflexids, the mandibles with deep ectoflexids on the lower premolars suggest their attributions to H. forstenae. The presence of a deep ectoflexid on p2 may be interpretable as an intraspecifically variable feature in H. forstenae, and can also be found in H. dermatorhinum. Besides the Hipparion material, at least 8 species of large mammals occur at the Gaojiashan locality, including Adcrocuta eximia, Chilotherium wimani, Shansirhinus ringstroemi, Eucladoceros cf. proboulei, Palaeotragus cf. coelophrys, Giraffidae gen. et sp. indet., and the previously studied Promephitis hootoni and Eostyloceros hezhengensis. Although the sample from Gaojiashan shares five species with the Yangjiashan fauna, the Gaojiashan fossil assemblage may date to the Baodean because of the presence of H. forstenae. The overall taxonomic composition of the Gaojiashan assemblage at least suggests an approximate Baodean age, which would imply survival of C. wimani into the Baodean of the Linxia Basin.     

A new genus and species of filamentous microfossil of cyanobacterial affinity from Early Silurian fluvial environments (lower Massanutten Sandstone,Virginia, USA)

Fossils reported previously from the Early Silurian (Llandovery) lower Massanutten Sandstone (Virginia, USA) are formally described here as Prattella massanuttense gen. & sp. nov. Organization into cellular filaments embedded in extracellular matrix, the sizes of cells and filaments and the fluvial origin of deposits that host the fossils are all consistent with cyanobacterial affinity. Prattella massanuttense combines preservation as carbonaceous compression at a macroscopic scale with cellular preservation by mineral replacement of cell contents at a microscopic scale. These fossils provide the earliest direct evidence for the occurrence of cyanobacteria in fluvial habitats and add to the knowledge of terrestrial ecosystems that hosted early stages of land plant evolution. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 284–289.     

Tertiary plant microfossil assemblages from the Pannonian Depression (rumania) and their palaeoecology

The paper represents an overall presentation of the Tertiary plant microfossils in the westernmost part of Rumania, the Pannonian Depression. Besides pollen grains and microspores, other categories, such as dinoflagellates, acritarchs, diatoms and silicoflagellates have also been considered. A complex treatment of these microfossils permitted making an original stratigraphical zonation. Nine subdivisions of a preliminary character have been delimited which correspond to the Eocene, Miocene and Pliocene times. An attempt was made to show a parallelism between these subdivisions and stratigraphical equivalents in the area of the Central Paratethys to which the zone investigated belongs.     

A New Late Silurian or Early Devonian Thelodont from the Boothia Peninsula, Arctic Canada

Isolated scales of Boothialepis thorsteinssoni gen. et sp. nov. are described from a fossiliferous calcareous dolomite at the base of the Somerset Island Formation of the Boothia Peninsula, Arctic Canada. A new family, Boothialepididae (Thelodonti), is established on features of the scale morphology and histology. The new genus and species are distinguished by characteristics of crown sculpture, neck, and unusual size of the base. Two other thelodonts, Nikolivia elongata Karatajūtė-Talimaa and Canonia grossi Vieth, and an acanthodian, Poracanthodes sp., are described from the same stratigraphical level. Thelodonts have not previously been described from the Boothia Peninsula. Conodont-based correlation indicates a Late Silurian age for the base of the Somerset Island Formation on the Boothia Peninsula. Correlation of the beds with precisely dated microvertebrates in the Read Bay section on Cornwallis Island enables the age of the horizon with the new species to be determined as Early Devonian.