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Aragosaurus (sauropod from Spain) anatomy, phylogeny, stratigraphic age



From: Ben Creisler
bcreisler@gmail.com

A new online paper:


Rafael Royo-Torres, Paul Upchurch, Philip D. Mannion, Ramón Mas,
Alberto Cobos, Francisco Gascó, Luis Alcalá and José Luis Sanz (2014)
The anatomy, phylogenetic relationships, and stratigraphic position of
the Tithonian–Berriasian Spanish sauropod dinosaur Aragosaurus
ischiaticus.
Zoological Journal of the Linnean Society (advance online publication)
DOI: 10.1111/zoj.12144
http://onlinelibrary.wiley.com/doi/10.1111/zoj.12144/abstract


The first dinosaur to be named from Spain, the sauropod Aragosaurus
ischiaticus Sanz, Buscalioni, Casanovas and Santafé 1987, is known
from associated postcranial remains of one individual from the Las
Zabacheras site in Galve, Teruel Province, Spain. Results of recent
fieldwork confirm that the Las Zabacheras site represents a deltaic
sediment complex in the Villar del Arzobispo Formation with a
Tithonian–Berriasian (latest Jurassic–earliest Cretaceous) age.
Description of the anatomy of Aragosaurus (including several
previously undescribed elements) enables a re-evaluation of this
taxon's relationships. Aragosaurus ischiaticus has six autapomorphies
in the axial and appendicular skeleton, including the presence of
epipophysis-like protuberances on middle caudal postzygapophyses.
Phylogenetic analyses, using three independent data sets, support the
view that Aragosaurus is a basal macronarian sauropod, lying outside
of Titanosauriformes. Aragosaurus possesses derived states that are
shared with basal Titanosauriformes, indicating that some characters
previously considered to represent titanosauriform synapomorphies have
a slightly wider distribution. A tooth, previously described as
Aragosaurus, cannot be referred to this taxon as it was recovered from
a different locality, and there are no overlapping elements with the
holotype; it is here regarded as representing an indeterminate
titanosauriform. These results, combined with new data on the
stratigraphic age of Aragosaurus, demonstrate that basal macronarian
sauropods were present in Europe at the end of the Late Jurassic,
alongside more derived titanosauriforms. Aragosaurus is one of four
genera of sauropod recovered from the Villar del Arzobispo Formation
in Spain, making the latter an important contributor to our
understanding of Late Jurassic sauropod diversity alongside the
well-known contemporaneous faunas of the African Tendaguru Formation
and the North American Morrison Formation.