Geoscience Reference
In-Depth Information
Accurate dating of the fossil record is essential to
form hypotheses about the factors that may have
triggered the diversification of a specific group.
Blieck et al. provide an updated biostratigraphical
review of tetrapod occurrences in the Late Devo-
nian. This strengthens the recognition of two epi-
sodes of diversification and the probable link of
the first episode to the low concentration of
oxygen in the atmosphere during the Givetian-
Frasnian time slice. Based on their data, these
authors also favour an 'out of Euramerica' scenario
where tetrapods originate on the Old Red Sandstone
palaeocontinent
temnospondyls from the Permian freshwater-lake
deposits of the Saar-Nahe Basin in southwest
Germany. Finally, the contribution by Laurin
et al. presents a historical review of concepts and
evidence of the habitat of extant amphibians as
well as Palaeozoic sarcopterygians. The authors
conclude that on the basis of current knowledge
there is no definitive reason to expect early stegoce-
phalians to have been confined to freshwater
palaeoenvironments. They present evidence for a
widespread tolerance of salt- and brackish waters
in Palaeozoic stegocephalians.
We hope that this topic will stimulate further
multidisciplinary investigations, developments and
use of new analytical techniques as well as contrib-
ute
in
a
pre-Pangean
configuration
of landmasses.
The last two contributions demonstrate how
morphological, histological and taphonomical ana-
lyses of Palaeozoic tetrapods, in the context of
their palaeogeographical occurrence, can contribute
to constrain their habitats, palaeoenvironments and
ecologic requirements. Sanchez et al. applied
palaeohistological analyses to track changes in
food availability, palaeoclimatic conditions and/or
the presence of predators in the habitat of small
to new
ideas and
approaches
to the study
of terrestrialization.
Reference
Gensel,P.G.&Edwards, D. (eds) 2001. Plants Invade
the Land: Evolutionary and Environmental Perspec-
tives. Columbia University Press, New York.
