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...

Late Devonian (Frasnian) abiotic marine calcite has been microsampled and analyzed for R’Sr/*6Sr ratios, 6’*0 and d13C values, and minor element concentrations. Portions of marine cement crystals from the Alberta and Canning Basins have escaped diagenetic alteration and preserve original marine S180 values f-4.8%0 + 0.5, PDB), Si3C values (+2.0 to +3.0b, PDB), *‘Sr/*6Sr ratios (0.70805 + 3), an...

Past research on the emergence of digit-bearing tetrapods has led to the widely accepted premise that this important evolutionary event occurred during the Late Devonian. The discovery of convincing digit-bearing tetrapod trackways of early Middle Devonian age in Poland has upset this orthodoxy, indicating that current scenarios which link the timing of the origin of digited tetrapods to specif...

9. Gardiner, B. G. The relationships of the palaeoniscid ®shes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia. Bull. Brit. Mus. Nat. Hist. (Geol.) 37, 173±428 (1984). 10. Young, G. C. New information on the structure and relationships of Buchanosteus (Placodermi: Euarthrodira) from the Early Devonian of New South Wales. Zool. Jour. Linn. S...

In an earlier paper^ I described the new genus Brooksma from a series of sediments in southeastern Alaska tentatively referred to the upper Silurian. In that paper will be found a brief discussion of the faunal affinities of the series. A more detailed study of the Brooksina fauna together with the famias of lower and liighei horizons strengthens the belief that the formations in question shoul...