CONTENTS Introduction 85 Brief overview of Cambrian radiation of bilateral animals 86 Rapid diversification of animal phyla 86 Characteristic body plan of each phylum 86 Early establishment of body plan 87 Altered expression of embryonic genes resulting in new body plans 87 Silurian–Devonian radiation of land plants 88 Did early land plants diverge in a rapid evolutionary radiation? 88 Are the ...

The discovery of arbuscules in Aglaophyton major, an Early Devonian land plant, provides unequivocal evidence that mycorrhizae were established >400 million years ago. Nonseptate hyphac and arbuscules occur in a specialized meristematic region of the cortex that continually provided new cells for fungal infection. Arbuscules are morphologically identical to those of living arbuscular mycorrhiza...

Steams, C. and Van der Voo, R., 1987. Paleomagnetic results from the Lower Devonian Llandstadwell Formation, Dyfed, Wales. Tectonophysics, 143: 329-334. A paleomagnetic investigation of the Lower Devonian Llandstadwell Eormation in southwest Wales has yielded a characteristic direction (declination = 196’. inclination = 5’) that passes a fold test. Comparison of the corresponding virtual geomag...

During the mid-Palaeozoic, vascular land plants (i.e., tracheophytes) underwent a great radiation that triggered development of biosphere – so-called Silurian–Devonian terrestrial revolution. However, little is known about how different plant groups impacted this process. A newly constructed dataset macrofossil genera used to characterize tempo and mode vegetation it spread out over subaerial h...

Exceptional braincase preservation in some Devonian placoderm fishes permits interpretation of muscles and cranial nerves controlling eye movement. Placoderms are the only jawed vertebrates with anterior/posterior obliques as in the jawless lamprey, but with the same function as the superior/inferior obliques of other gnathostomes. Evidence of up to seven extraocular muscles suggests that this ...

about 35 samples were collected from lower and upper parts of the proposed frasnianamennian boundary in three sections of upper devonian marine sediments of the kerman province. the biostratigraphical and geochemical studies indicate that about 45% extinction of brachiopods probably caused by the frasnian-famennian bioevents, which is slightly higher than thr rate of devonian-carboniferous exti...

The Geirud Formation consists mainly of clastic sediments which are interbedded with limestone stringers. This rock unit is well-exposed along the Central Alborz Range in northern Iran. The Geirud Formation rests unconformably on the Mila Formation (Upper Cambrian) and is conformably overlain by the Mobarak Formation (Lower Carboniferous). This study was undertaken to determine the geologi...

Recent discoveries of previously unknown fossil forms have dramatically transformed understanding of many aspects of the fish-tetrapod transition. Newer paleobiological approaches have also contributed to changed views of which animals were involved and when, where, and how the transition occurred. This review summarizes major advances made and reevaluates alternative interpretations of importa...

BACKGROUND AND AIMS The evolution of complex rooting systems during the Devonian had significant impacts on global terrestrial ecosystems and the evolution of plant body plans. However, detailed understanding of the pathways of root evolution and the architecture of early rooting systems is currently lacking. We describe the architecture and resolve the structural homology of the rooting system...