نتایج جستجو برای: some jurassic and cretaceous sediments sub
تعداد نتایج: 16973334 فیلتر نتایج به سال:
A single brachiosaurid sauropod cervical vertebra from the Wessex Formation (Barremian, Early Cretaceous) of the Isle of Wight is remarkable for its size. With a partial centrum length (i.e., excluding evidence of the anterior condyle) of 745 mm it represents the largest sauropod cervical reported from Europe and is close in size to cervical vertebrae of the giant brachiosaurid Brachiosaurus br...
Flower, enclosed ovule and tetrasporangiate anther are three major characters distinguishing angiosperms from other seed plants. Morphologically, typical flowers are characterised by an organisation with gynoecium and androecium surrounded by corolla and calyx. Theoretically, flowers are derived from their counterparts in ancient ancestral gymnosperms. However, as for when, how and from which g...
Mawsoniidae are a fossil family of actinistian fish popularly known as coelacanths, which are found in continental and marine paleoenvironments. The taxon is considered monophyletic, including five valid genera (Axelrodichthys, Chinlea, Diplurus, Mawsonia and Parnaibaia) and 11 genera with some taxonomical controversy (Alcoveria, Changxingia, Garnbergia, Heptanema, Indocoelacanthus, Libys, Lual...
The latitudinal biodiversity gradient (LBG)-the pattern of increasing taxonomic richness with decreasing latitude-is prevalent in the structure of the modern biota. However, some freshwater taxa show peak richness at mid-latitudes; for example, extant Testudines (turtles, terrapins and tortoises) exhibit their greatest diversity at 25° N, a pattern sometimes attributed to recent bursts of clima...
Owing to the assumed lack of deep-sea macrofossils older than the Late Cretaceous, very little is known about the geological history of deep-sea communities, and most inference-based hypotheses argue for repeated recolonizations of the deep sea from shelf habitats following major palaeoceanographic perturbations. We present a fossil deep-sea assemblage of echinoderms, gastropods, brachiopods an...
Morphological responses of nonmammalian herbivores to external ecological drivers have not been quantified over extended timescales. Herbivorous nonavian dinosaurs are an ideal group to test for such responses, because they dominated terrestrial ecosystems for more than 155 Myr and included the largest herbivores that ever existed. The radiation of dinosaurs was punctuated by several ecological...
The Upper Jurassic to Lower Cretaceous shallow water platform carbonates of the Northern Calcareous Alps (Plassen Formation, “Lärchberg Formation”) and the resedimented deposits of the latter within basinal series (Barmstein Limestone, Tressenstein Limestone) are currently under re-investigation (SCHLAGINTWEIT et al., 2003; GAWLICK et al., 2005). This shallow water development is directly linke...
Calcareous nannofossil assemblages recovered from a long, continuous section have been described from the Sarayan region in Lut Block in east Iran. The marine Upper Cretaceous sediments of this section yield medium diverse and well-preserved calcareous nannofossil assemblages. A structural analysis of Upper Cretaceous calcareous nannofloras has revealed 30 nannofossil species. A revised zonatio...
New flea-like fossils from China provide a rare, tantalizing glimpse of bizarre insects in the Cretaceous and Jurassic. Possibly the oldest flea-like animals known, they provide a challenge to the functional morphologist to infer which animals they may have targeted.
Growth ring analysis on silicified coniferous woods from the Missão Velha Formation (Araripe Basin - Brazil) has yielded important information about periodicity of wood production during the Early Cretaceous in the equatorial belt. Despite warm temperatures, dendrological data indicate that the climate was characterized by cyclical alternation of dry and rainy periods influenced by cyclical pre...
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