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Cretaceous tetrapod faunal turnover

From: Ben Creisler

A new online paper:

Roger B.J. Benson, Philip D. Mannion, Richard J. Butler, Paul
Upchurch, Anjali Goswami &, Susan Evans (2012)
Cretaceous tetrapod fossil record sampling and faunal turnover:
Implications for biogeography and the rise of modern clades.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication),

We use newly compiled data on global occurrences of Cretaceous
lepidosaurs, mammals and crocodylomorphs, and existing data on
dinosaurs, to investigate faunal turnover and fossil record
heterogeneity. Statistically significant relationships between many
clade-specific fossil record sampling proxies within major continental
areas (e.g. European mammal-bearing formations) suggest that temporal
patterns of fossil record sampling intensity of the most abundant
tetrapod clades are similar to each other, with a few exceptions that
might reflect clade-specific facies preferences or differences in
worker effort (especially in poorly-sampled regions such as Gondwana).
However, the absence of strong statistical relationships between
tetrapod sampling proxies from different continental areas suggests
that there is no unified ‘global’ sampling signal for terrestrial
tetrapods. The Cretaceous witnessed substantial faunal turnover and
the rise of many ‘advanced’ clades that today dominate terrestrial
faunas. Despite strong spatiotemporal heterogeneity in sampling of the
Cretaceous tetrapod record, it is clear that this transition occurred
in a spatiotemporally staggered fashion. Thus, it cannot be attributed
to a temporally localized early Late Cretaceous (Cenomanian–Turonian)
extinction event. Many advanced clades, including eutherian mammals,
iguanian and gekkotan squamates, and the main cryptodiran turtle crown
clades first appeared, or first attained high fossil diversities, in
Asia. However, relatively poor sampling and dating of ‘middle’
Cretaceous terrestrial deposits means that hypotheses of Asian, rather
than Laurasian, diversifications remain tentative. Differences between
Gondwanan and Laurasian faunas became progressively greater during the
Cretaceous, and although many Gondwanan clades survived the
end-Cretaceous extinction event, these only survive to the present as
relictual populations with narrow geographic ranges (e.g. monotremes,