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Triassic provincialization of terrestrial faunas after Permian extinction



From: Ben Creisler
bcreisler@gmail.com


A new online paper:


Christian A. Sidor, Daril A. Vilhena, Kenneth D. Angielczyk, Adam K.
Huttenlocker, Sterling J. Nesbitt, Brandon R. Peecook, J. Sébastien
Steyer, Roger M. H. Smith, and Linda A. Tsuji (2013)
Provincialization of terrestrial faunas following the end-Permian mass
extinction.
Proceedings of the National Academy of Sciences (advance online publication)
doi: 10.1073/pnas.1302323110
http://www.pnas.org/content/early/2013/04/24/1302323110.abstract?sid=ca247696-0f82-4a3b-97ae-ff99a2fcd07b



In addition to their devastating effects on global biodiversity, mass
extinctions have had a long-term influence on the history of life by
eliminating dominant lineages that suppressed ecological change. Here,
we test whether the end-Permian mass extinction (252.3 Ma) affected
the distribution of tetrapod faunas within the southern hemisphere and
apply quantitative methods to analyze four components of biogeographic
structure: connectedness, clustering, range size, and endemism. For
all four components, we detected increased provincialism between our
Permian and Triassic datasets. In southern Pangea, a more homogeneous
and broadly distributed fauna in the Late Permian (Wuchiapingian, ~257
Ma) was replaced by a provincial and biogeographically fragmented
fauna by Middle Triassic times (Anisian, ~242 Ma). Importantly in the
Triassic, lower latitude basins in Tanzania and Zambia included
dinosaur predecessors and other archosaurs unknown elsewhere. The
recognition of heterogeneous tetrapod communities in the Triassic
implies that the end-Permian mass extinction afforded ecologically
marginalized lineages the ecospace to diversify, and that biotic
controls (i.e., evolutionary incumbency) were fundamentally reset.
Archosaurs, which began diversifying in the Early Triassic, were
likely beneficiaries of this ecological release and remained dominant
for much of the later Mesozoic.