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Latest Cretaceous dinosaur communities of southwestern Europe



Ben Creisler
bcreisler@gmail.com

Two new papers:

Bernat Vila, Albert G. Sellés & Stephen L. Brusatte (2015)
Diversity and faunal changes in the latest Cretaceous dinosaur
communities of southwestern Europe.
Cretaceous Research (advance online publication)
doi:10.1016/j.cretres.2015.07.003
http://www.sciencedirect.com/science/article/pii/S0195667115300264

Characterization of macroecological patterns for latest Cretaceous
dinosaur communities is essential to understand how those faunas were
changing during the run-up to the Cretaceous-Paleogene extinction
event, and thus the cause of the extinction. Outside of the
well-studied latest Cretaceous dinosaurs of North America,
southwestern Europe (France, Spain and Portugal) preserves one of the
richest end-Cretaceous dinosaur fossil records, as it has produced
hundreds of dinosaur fossil localities. We compiled a comprehensive
database of all dinosaur fossil occurrences from the uppermost
Cretaceous of the Ibero-Armorican region and analyze it statistically,
providing the first numerical study of the ecological and taxonomic
diversities of these communities. Our study corroborates previous work
that has identified a major faunal change in the latest Cretaceous
terrestrial vertebrate assemblages, and places this event around the
C31r-C31n reversal, in the early late Maastrichtian (c. 69 Ma).
Significant differences in ecological diversity metrics (dominance,
Shannon and Simpson) characterize the pre- and post-turnover
assemblages. The turnover event, therefore, did not only lead to a
taxonomic replacement but also important reorganizations in the
structure of dinosaur communities. Herbivorous dinosaurs suffered the
most dramatic alterations across the turnover, in terms of relative
dominances, by shifting their contributions within the communities
(hadrosauroids replacing titanosaurids as the dominant taxon in the
medium-to large-bodied herbivore niche) or even disappearing
(rhabdodontids and nodosaurids). The carnivores apparently maintained
similar relative abundances before and after the turnover, and the
relative proportions between carnivorous and herbivorous taxa remained
static through time. Further improvement of the present database might
allow for the identification of new ecological patterns, and
higher-resolution comparison with the North American records.

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Josep Marmi, Alejandro Blanco, Víctor Fondevilla, Fabio Marco Dalla
Vecchia, Albert G. Sellés, Alba Vicente, Carles Martín-Closas, Oriol
Oms & Àngel Galobart (2015)
The Molí del Baró-1 site, a diverse fossil assemblage from the
uppermost Maastrichtian of the southern Pyrenees (north-eastern
Iberia).
Cretaceous Research (advance online publication)
doi:10.1016/j.cretres.2015.06.016
http://www.sciencedirect.com/science/article/pii/S0195667115300227


Highlights

Molí del Baró-1 is a diverse fossil assemblage from the upper
Maastrichtian Iberia.
It includes plants, invertebrates and vertebrates.
Its crocodile record is among the most diverse in the Maastrichtian of Europe.
Deposition mostly occurred in a pool formed at the edge of a river meander.
Crocodiles, theropods and hadrosauroids were the main faunal elements
of this biota.

Abstract

The Molí del Baró-1 site (north-eastern Iberia) has yielded one of the
richest fossil assemblages of the continental upper Maastrichtian from
western Europe. It includes abundant plant (charophytes, sporomorphs,
angiosperm leaves, seeds and logs), invertebrate (mollusc shells,
partial insect exoskeletons and eggs) and vertebrate (teeth, bones,
eggshells) fossils. The fossil assemblage is composed of both
parautochthonous and allochthonous remains that mostly deposited in a
pool formed at the edge of a meandering river. Plant megafossil
evidence suggest that at least three angiosperm species (a willow-like
dicot, palms and a likely typhacean monocot) formed the plant
community growing in this fluvial environment. Tooth remains indicate
that crocodylomorphs were diverse (including atoposaurids,
ziphosuchians and eusuchians) which together with small theropod
dinosaurs likely consumed prey carcasses or scavenged near the
depositional setting. Prismatoolithid eggshells also suggest the
presence of nearby nesting area of theropods. On the other hand,
hadrosauroids apparently dominated phytophagous faunas including
lambeosaurines as well as more basal forms. The taxonomic composition
of the Molí del Baró-1 site matches the expected for the timespan and
environment and represents a relevant locality to know the diversity
of the latest Cretaceous terrestrial ecosystems in south western
Europe.

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