منابع مشابه
The Cleveland Museum of Natural History
Arthrodires were predatory vertebrates of the Devonian seas, with simple lower jaws conducible to examination of feeding across growth, evolution, and local diversity. 2D finite element analyses (FEA) of arthrodire mandibles (scaled to equivalent length and force, and checked against a 3D control), and a new method of stress integration, enable extensive comparisons of bite stress. FEA indicate...
متن کاملDivision Rhyniophyta - Upper Silurian to Middle Devonian
Among the oldest convincing fossils of early vascular land plants are those of the Division Rhyniophyta. The members of this division consist of: (1) simple axes with cuticle, stomates, epidermis, cortex and a terete (circular) centrarch xylem (xylem development occurs from the center of the stem to the periphery), without well-developed appendages or roots; (2) simple, isotomous branching syst...
متن کاملGlyptolepis from the Middle Devonian of Scotland
The Rhipidistia (Osteichthyes, Crossopterygii) comprise three superfamilies of Paleozoic fossil fishes, the Holoptychoidea, Osteolepoidea and Rhizodontoidea. Of these the members of the Holoptychoidea (families Holoptychidae and Porolepidae) are by far the least well known, and consequently there exists a considerable gap in our knowledge of the evolution of the Rhipidistia as a whole. The aim ...
متن کاملMiddle Devonian liverwort herbivory and antiherbivore defence.
To test the extent of herbivory in early terrestrial ecosystems, we examined compression-impression specimens of the late Middle Devonian liverwort Metzgeriothallus sharonae, from the Catskill Delta deposit of eastern New York state. Shale fragments of field-collected specimens were processed by applying liquid nitrocellulose on exposed surfaces. After drying, the film coatings were lifted off ...
متن کاملWoodland Hypothesis for Devonian Tetrapod Evolution
The rarity of Devonian tetrapods and the absence of tetrapods during the first 14 million years of the Mississippian (Romer’s Gap) have inspired hypotheses of fish-tetrapod evolutionary transition as an escape from difficult habitats such as deserts or stagnant waters. These hypotheses and Romer’s Gap are tested here using depth to calcic horizon in paleosols of the northern Appalachians as a p...
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ژورنال
عنوان ژورنال: Nature
سال: 1975
ISSN: 0028-0836,1476-4687
DOI: 10.1038/254556a0