共查询到20条相似文献,搜索用时 0 毫秒
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I. N. Kosenko 《Paleontological Journal》2019,53(6):583-592
The morphology and shell microstructure of smooth exogyrid oysters from the Upper Maastrichtian of the Mountainous Crimea (SW Russia) are studied. Their shell microstructure consists of a simple regularly foliated, irregular crossed foliated, and transitional irregular simple prismatic/irregular complex crossed foliated structures. The latter has been only identified in oysters of the genus Rhynchostreon Bayle. Along with specific shell morphology, it allows to attribute the studied oysters to the species Rhynchostreon aralensis (Arkhangelsky, 1912). The occurrence of the genus Rhynchostreon in the Upper Maastrichtian of the Mountainous Crimea allows to clarify its stratigraphic distribution. 相似文献
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L. Gereltsetseg 《Paleontological Journal》2009,43(6):699-701
Charophyte assemblage is described from the Naran Member of the Tsagaan sair section (Upper Paleocene). A new species, Mesochara cornuta, is described. 相似文献
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Journal of Ichthyology - In the present study, for the first time we isolated and characterized the complete mitochondrial genome sequence of the endangered Farsi killifish Aphanius farsicus by... 相似文献
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隐子蕨属(水龙骨科)植物在中国的首次承认 总被引:4,自引:0,他引:4
首次承认水龙骨科(Polypodiaceae)隐子蕨属(Crypsinus)植物在中国的分布。文中列出了该属与假瘤蕨属(Phymatopteris)和修蕨属(Selliguea)的区别特征,给出隐子蕨属植物在中国的唯一一种——三指隐子蕨(Crypsinus trilobus)的文献引证,特征描述并附图。 相似文献
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Journal of Ichthyology - The paper reports the first find of the marbled spinefoot Siganus rivulatus Forsskål et Niebuhr, 1775, which is a new species for the Black Sea, at the southeastern... 相似文献
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A systematic survey of intrastratal trace fossil distribution in flysch deposits shows that the ichnocoenoses form along two radically different modes: 1. Post‐turbidite ichnocoenoses begin with synchronous colonization. Further development of the tiered structure depends primarily on sediment composition, textural profile and oxygen levels. Different species respond to these factors according to their oxygen tolerances, penetration potentials and nutritional requirements. 2. Pre‐turbidite ichnocoenoses result from successional colonization, depending on the duration of background sedimentation. The depth of subsequent turbidite erosion determines which tier becomes preserved. 相似文献
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Donald L. Lofgren Benjamin E. Scherer Charles K. Clark Barbara Standhardt 《Journal of Mammalian Evolution》2005,12(1-2):77-97
A single tooth referred to Stygimys kuszmauli recovered at the Gas Tank Hill locality from Puercan strata of the North Horn Formation represents the first record of Stygimys from Utah. S. kuszmauli now occurs in both proposed north–south late Puercan biogeographic provinces, which reduces statistical support for provinciality. A new species from Texas, Stygimys vastus, is described. Of the five species previously referred to Stygimys, S. kuszmauli, Stygimys camptorhiza, Stygimys jepseni, and Stygimys teilhardi are valid, but Stygimys cupressus is synonymous with S. kuszmauli. The type of S. jepseni is restricted to a single p4 as the m1 thought to be from the same individual represents another multituberculate genus. Five sites, including Gas Tank Hill that comprise the Gas Tank Hill Local Fauna are widely dispersed in slumped strata which may differ in age, are located in a mostly floodplain depositional setting, and are small surface collected samples. Therefore, biogeographic analyses that compare the Gas Tank Hill Local Fauna to large samples collected from channel fills using screenwash techniques should be employed with caution. Stygimys has a relatively broad geographic and geochronologic distribution, but it is usually rare in Late Cretaceous and Early Paleocene mammalian assemblages. The recent recovery of Stygimys after more than 60 years of collecting in the North Horn Formation suggests that further sampling in other non-marine basins in Western North America will eventually yield additional specimens of the genus. 相似文献
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《Comptes Rendus Palevol》2008,7(7):401-405
Paleolomatia menatensis gen. and sp. n., oldest Bombyliidae sensu stricto, is described from the Paleocene of Menat (France). The new genus, based on the wing venation, is attributed to the rather ‘derived’ subfamily Lomatiinae, strongly supporting a Late Cretaceous age for the diversification of the pollinator bee flies, in relation with the floristic changes and the angiosperm radiation that occurred at the same time. 相似文献
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T. N. Smirnova 《Paleontological Journal》2014,48(1):41-46
The shell structure of the Early Cretaceous rhynchonellids from Crimea has not been previously studied. First data on the shell structure of Berriasian rhynchonellids from the family Praecyclothyrididae Makridin, 1964 from southwestern and central Crimea are presented. Sulcirhynchia semenovi (Moisseev, 1939), S. berriasensis (Lobacheva, 1980), S. gracilis (Lobacheva, 1977), Belbekella airgulensis Moisseev, 1939, B. mutabilis Lobacheva, 1983, B. minor Lobacheva, 1983 and partly Lamellaerhynchia rectimarginata (Smirnova, 1972) are studied. The shell wall of most species consists of three layers: external (finely or coarsely crystalline), fibrous, and prismatic layers. The layers are usually strongly recrystallized, especially external and prismatic layers. New fibers were formed by repeated dichotomy of ridges in different areas of the fibrous layer independently of the distance from the anterior margin. 相似文献
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Kenshu Shimada 《Environmental Biology of Fishes》2002,63(3):309-319
The dentitions of lamniform sharks possess a unique heterodonty, the lamnoid tooth pattern. However, in embryos, there are 'embryonic' and 'adult' dentitions. The teeth in the embryonic dentition are peg-like and appear to be attached to the jaw in an acrodont fashion. The adult dentition is characterized by the presence of replacement tooth series with the lamnoid tooth pattern. The embryonic–adult transition in dentitions appears at around 30–60cm TL. Tooth replacement generally begins before birth in embryos with adult dentitions. The adult dentition becomes functional just before or after parturition. An embryo of one species (Lamna nasus) shows a tooth directly on the symphysis of the upper jaws, marking the first record of a medial tooth for the order Lamniformes. 相似文献
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We describe the manual and digital methods used to prepare an exceptional fossil specimen, as well as the composition of this specimen revealed by these methods. The fossil, a rhinobatoid, is 3-dimensionally preserved in a concretion. Fossils like these are seldom encountered, because flat-bodied animals are traditionally preserved in lithographic beds, or more commonly, are only represented by disassociated dentition. Manual preparation was best conducted with needles and a local application of buffered formic acid and neutralised sodium carbonate. High-resolution computed tomography and post-analysis using the invert ramp option in VGStudio Max 2.0 produced the best results to see the complete skeleton of this specimen. The specimen is distinguishable from the only other known 3D preserved fossil rhinobatoid, the Lower Cretaceous (Albian) genus 2Iansan, and is probably a member of Platyrhinidae. 相似文献
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Conrad van den Ende 《Ichnos》2013,20(2):73-75
A test of the Lower Paleocene holasteroid echinoid Echinocorys ex. gr. scutata Leske from Göynük, Turkey, preserves a Planolites beverleyensis (Billings) burrow close to the internal surface. Identification of such a specimen is fortuitous; only where the test has broken cleanly away from the internal mould can such burrows be exposed, if present at all. A second specimen, from the Upper Cretaceous of Norfolk, England, bears a sinuous boring identified as Planolites montanus Richter. 相似文献
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Jean-Claude Rage Grégoire Métais Annachiara Bartolini Imdad A. Brohi Rafiq A. Lashari Laurent Marivaux Didier Merle Sarfraz H. Solangi 《Geobios》2014
We report here the discovery of madtsoiid snake remains from the early Paleocene Khadro Formation (Ranikot Group, Sindh, Southern Pakistan). These specimens consist of vertebrae and are referred to Gigantophis. This is the first report of Gigantophis from outside of Africa. The problem of the generic distinction between Gigantophis and Madtsoia is stressed. The specimens from Pakistan slightly differ from the single species (G. garstini) referred to the genus Gigantophis, but the available material does not allow further considerations and the fossil is referred to as Gigantophis sp. However, Gigantophis sp. from the Khadro Formation is more closely related to G. garstini, that is known only from the middle and late Eocene of northern Africa, than to any other species, thus suggesting dispersal between these two areas during the Paleocene or earlier. These results are consistent with the hypothesis of intermittent dispersals between the Indo-Pakistan Plate and Africa suggested by other fossil evidences. 相似文献
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Per Inge Berge 《Cell and tissue research》1979,201(2):181-195
Summary The ultrastructure of the heart in Chimaera monstrosa L. is described. The endocardial and the epicardial cells are similar in the three cardiac regions. Myocardial cells show small variations.The myofibre, 4–6 m thick, contains one or a few myofibrils. Each myosin filament is surrounded by six actin filaments. The sarcomere banding pattern includes the Z-, A-, I-, M-, N-, and H-band. End-to-end attachments between myofibres are composed of alternating desmosomes and fasciae adhaerentes. Desmosomes and nexuses occur between longitudinally oriented cell surfaces. The sarcoplasmic reticulum is poorly developed but well defined. Peripheral coupling-like structures are common, T-tubules are absent. Membrane bound dense bodies occur in all regions. Areas with ribosomes and single myosin filaments are often seen.The epicardial cells have a regular hexagonal surface and are much thicker than the endocardial cells. Numerous short and a few longer cytoplasmic extensions face the pericardial cavity.The fiat endocardial cells contain a large nucleus and small amounts of cytoplasm. 相似文献
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Entomological Review - Genus and species of Bathrips melanicornis (Shumsher) (Thripidae: Thripinae) are recorded from Iran, Ilam Province for the first time. Specimens of this species have been... 相似文献
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Ichthyological Research - Dampierosa daruma Whitley 1932 and Erosa erosa (Cuvier in Cuvier and Valenciennes 1829) (Synanceiidae) were redescribed on the basis of both primary type and non-type... 相似文献