نتایج جستجو برای: middle jurassic
تعداد نتایج: 158491 فیلتر نتایج به سال:
BACKGROUND Anomopterellidae was originally classified as a family within the Evanioidea, and later lowered to a subfamily, Anomopterellinae, of Praeaulacidae. Up to date, only Rasnitsyn 1975, with four species, was assigned to Anomopterellinae. Due to their special wing venation and their metasomal attachment similar to those known in Evanioidea, the systematic position of Anomopterellinae in E...
A series of spectacular discoveries have transformed our understanding of Mesozoic mammals in recent years. These finds reveal hitherto-unsuspected ecomorphological diversity that suggests that mammals experienced a major adaptive radiation during the Middle to Late Jurassic. Patterns of mammalian macroevolution must be reinterpreted in light of these new discoveries, but only taxonomic diversi...
Mesozoic strata in the Cowhole Mountains, eastern Mojave block California, include 200–800 m of eolian quartz arenite (Aztec Sandstone) overlain by more than 575 m of silicic ignimbrites, lava flows, and minor sedimentary rocks (Cowhole volcanics). U-Pb zircon geochronologic data on a crystal-rich dacite lava flow in the Aztec Sandstone indicate that the sandstone is Middle Jurassic and is ther...
We describe a new genus and species of Mecoptera with siphonate mouthparts, Sinopolycentropus rasnitsynigen. et sp. n., assigned to the family Pseudopolycentropodidae Handlirsch, 1925. The specimen was collected from late Middle Jurassic nonmarine strata of the Jiulongshan Formation in Inner Mongolia, northeastern China. The new material provides additional evidence for an early diversification...
Despite increasing claims of pre-Cretaceous angiosperms, whether there really are angiosperms in the Jurassic is apparently still an open question for many people before further evidence is available. This question can only be answered by studying more Jurassic plant fossils. Here we report a fossil angiosperm, Yuhania daohugouensis gen. et sp. nov, from the Middle Jurassic of Inner Mongolia, C...
Pliosaurids were a long-lived and cosmopolitan group of marine predators that spanned 110 million years and occupied the upper tiers of marine ecosystems from the Middle Jurassic until the early Late Cretaceous. A well-preserved giant pliosaurid skull from the Late Jurassic Kimmeridge Clay Formation of Dorset, United Kingdom, represents a new species, Pliosaurus kevani. This specimen is describ...
Microconchids are an extinct group of Spirorbis-like tentaculitoid tubeworms that dwelled in a variety of aquatic environments, ranging from normal marine, through brackish and hypersaline, to freshwater. An analysis of published microconchid occurrences focusing on their ecology and palaeoenvironmental distribution through geological time is conducted in order to establish the timing of microc...
the study area is located south of ghonabad in eastern iran. this area is situated between two major faults, darouneh to the north and dashtbyaz to the south. the movements of these faults cased major dislocation of this block. najmabad granodiorite to granite batholith is elongated trending east-west 2×8 km2. mineralization is associated with granite and monzonite. alteration zones are: propyl...
the present article is a review of a palaeobiogeographic analysis of jurassic ostracods from east africa, india and madagascar and includes also some general remarks on palaeobiogeography, biodiversity and ostracod ecology.the palaeobiogeographic study shows the high significance of this microfossil group for the reconstruction of palaeogeographic processes, particularly plate tectonic developm...
Sinoeuthemis daohugouensis gen. et sp. n. is the first record of the isophlebiopteran family Euthemistidae from Middle Jurassic of northeast China, while previously this family was restricted to the early Late Jurassic Kazakhstan. This new finding allows us to emend the family diagnosis with hindwing characters. This new species shows a mixture of characters alternatively present in different g...
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