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Taphonomy of Aeolosaurus, titanosaur sauropod from Cretaceous of Argentina (free pdf)



Ben Creisler
bcreisler@gmail.com

A new advance online paper:


Gabriel A. Casal, Lucio M. Ibiricu, José O. Allard, Rubén D. Martínez,
Marcelo Luna & Bernardo J. González Riga (2014)
Tafonomía del titanosaurio Aeolosaurus colhuehuapensis, Cretácico
Superior, Patagonia central, Argentina: un ejemplo de preservación en
facies fluviales de desbordamiento.
[Taphonomy of the titanosaur Aeolosaurus colhuehuapensis, Upper
Cretaceous, central Patagonia, Argentina: an example of preservation
in fluvial facies of overflow.]
Revista Mexicana de Ciencias Geológicas (advance online publication)
http://satori.geociencias.unam.mx/en_prensa/Casal-ENPRENSA.pdf

[text in Spanish]

English abstract:

Rests of Aeolosaurus colhuehuapensis, a titanosaur from the Colhué
Huapi Lake, in the southern Chubut Province, Argentina, were analyzed.
The materials under study include twenty one caudal vertebrae and
seven haemal arches. They were recovered articulated in facies of
overbank related to deposits of multi-channels fluvial systems of high
sinuosity in the currently denominated "stratus of the Colhué Huapi
Lake", Campanian-Maastricthian in age. These systems, displayed
important seasonal fluctuations in the paleo-download and they were
encompassed in a semiarid climate. The taphonomic history was inferred
from the analysis of several taphonomic characteristics present in the
bones and macro and microscopic sedimentologic observations. The
presence of tenuous longitudinal striation, the absence of bone
exfoliation, the articulate condition of the materials and the dorsal
bow of the caudal series, support a short period of subaerial exposure
with a rapid burial episode. The absence of abrasion marks in the
materials indicates that they had scarce or null transport; therefore,
they could be considered as autochthonous. The dorsal bow of the tail
shows an opisthotonus posture, also exhibited by some theropod and
sauropod dinosaurs, but undocumented in the Chubut Group. The recent
fluctuant climatic conditions with variation of humidity and drought
strongly influenced the preservation of the materials. The current
work is the first case of detailed taphonomic study of a dinosaur
preserved in facies of proximal plain for the Chubut Group. Finally,
the preservation of sauropod bones in those facies is relevant because
this type of sub-environment possess a high rate of sedimentary
deposition as well as scarce or null skeletal remains re-working which
favor the articulated skeletal element conservation. Thus, it is very
important for the taphonomic and phylogenetic analysis of the
titanosaur clade, where the majority of the taxa are represented by
isolated and unarticulated remains.