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...

In the original description of the Devonian tetrapod Ventastega curonica Ahlberg et al., 1994, Oleg Lebedev mentioned his finding of an uncatalogued, presumed postorbital bone from the Late Devonian of Latvia in the collection of fossil fishes in the Museum f r Naturkunde in Berlin (Ahlberg et al. 1994). The bone bears a dermal sculpture of radially arranged ridges and furrows and is crossed by...

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...

3-D microstructural analysis of 30 porphyroblastic samples from the Variscan orogen in NW-Iberia has revealed four sets of inclusion trails with distinctive geographic trends and relative timing. The chronological and orientational consistency of these microstructures provides a reference frame for the correlation of macroscopic structural successions. The two younger inclusion trail sets corre...