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South American Titanosauria species richness during Late Cretaceous

Ben Creisler

New in PLoS ONE:

Washington Luiz Silva Vieira, Kleber Silva Vieira, Rômulo Pantoja
Nóbrega, Paulo Fernandes Guedes Pereira Montenegro, Gentil Alves
Pereira Filho, Gindomar Gomes Santana, Rômulo Romeu Nóbrega Alves,
Waltécio Oliveira Almeida & Alexandre Vasconcellos (2014)
Species Richness and Evidence of Random Patterns in Assemblages of
South American Titanosauria during the Late Cretaceous
PLoS ONE 9(9): e108307.

The Titanosauria were much diversified during the Late Cretaceous, but
paleobiological information concerning these sauropods continues to be
scarce and no studies have been conducted utilizing modern methods of
community analysis to infer possible structural patterns of extinct
assemblages. The present study sought to estimate species richness and
to investigate the existence of structures in assemblages of the South
American Titanosauria during the Late Cretaceous. Estimates of species
richness were made utilizing a nonparametric estimator and null models
of species co-occurrences and overlapping body sizes were applied to
determine the occurrence of structuring in this assemblages. The high
estimate of species richness (n = 57) may have been influenced by
ecological processes associated with extinction events of sauropod
groups and with the structures of the habitats that provided abundant
support to the maintenance of large numbers of species. The
pseudocommunity analysis did not differ from that expected by chance,
indicating the lack of structure in these assemblages. It is possible
that these processes originated from phylogenetic inertia, associated
with the occurrence of stabilized selection. Additionally, stochastic
extinction events and historical factors may also have influenced the
formation of the titanosaurian assemblages, in detriment to ecological
factors during the Late Cretaceous. However, diagenetic and
biostratinomic processes, influenced by the nature of the sedimentary
paleoenvironment, could have rendered a random arrangement that would
make assemblage structure undetectable.