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Habitat preference of mosasaurs indicated by rare earth elements

Ben Creisler

A new online paper:

T.L. Harrell and A. Pérez-Huerta (2014)
Habitat preference of mosasaurs indicated by rare earth element (REE)
content of fossils from the Upper Cretaceous marine deposits of
Alabama, New Jersey, and South Dakota (USA).
Netherlands Journal of Geosciences (advance online publication)
DOI: http://dx.doi.org/10.1017/njg.2014.29

Knowledge of habitat segregation of mosasaurs has been based on
lithology and faunal assemblages associated with fossil remains of
mosasaurs and stable isotopes (δ13C). These approaches have sometimes
provided equivocal or insufficient information and, therefore, the
preference of habitat by different mosasaur taxa is still suboptimally
constrained. The present study is focused on the analysis of rare
earth element (REE) ratios of mosasaur fossils from the Upper
Cretaceous formations of western Alabama, USA. Results of the REE
analysis are used to infer the relative paleobathymetry associated
with the mosasaur specimens and then to determine if certain taxonomic
groups showed a preference for a particular water depth. Comparisons
are then made with mosasaur specimens reported in the literature from
other regions of North America from different depositional
environments. Results indicate that Mosasaurus, Platecarpus and
Plioplatecarpus may have preferred more restricted habitats based on
water depth whereas Tylosaurus and Clidastes favoured a wider range of
environments. Results also suggest that Plioplatecarpus lived in a
shallower environment than its Platecarpus predecessor. Although the
results of this study are encouraging, caution must be exercised
before drawing any final conclusions due to the small sample size of
most of the taxa analysed.