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Diplodocid sauropod from Late Jurassic of Argentina

Ben Creisler

A new online paper:

Oliver W. M. Rauhut, José L. Carballido & Diego Pol (2015)
A diplodocid sauropod dinosaur from the Late Jurassic Cañadón Calcáreo
Formation of Chubut, Argentina.
Journal of Vertebrate Paleontology (advance online publication)

Late Jurassic dinosaur faunas from the Southern Hemisphere are still
poorly known, and it thus remains unclear whether or not the famous
Tendaguru fauna (Kimmeridgian–Tithonian, Tanzania) represents a
typical Gondwanan dinosaur assemblage of that time. In South America,
only the Oxfordian–Kimmeridgian Cañadón Calcáreo Formation of Chubut
Province, Argentina, has yielded more than isolated Late Jurassic
dinosaur remains so far. Here we report fragmentary remains of a
dipolodocid sauropod from this unit, representing the first record of
this family from the Late Jurassic of South America. Incorporating the
basal macronarian Tehuelchesaurus, an unidentified brachiosaurid, the
dicraeosaurid Brachytrachelopan, and the diplodocid described here,
the taxonomic composition of the sauropod fauna from the Cañadón
Calcáreo Formation is remarkably similar to that of the Tendaguru
Formation, but also to roughly contemporaneous faunas in North America
and Europe. The diverse non-neosauropodan sauropod fauna known from
the early Middle Jurassic (Aalenian–Bajocian) of the same depositional
basin within Chubut Province is congruent with the dominance of
non-neosauropodan sauropods in continental faunas globally to at least
the Bathonian. These assemblages suggest a rapid faunal turnover
within sauropod faunas in the late Middle Jurassic-earliest Late
Jurassic at least in western Pangea, through which basal eusauropods
were replaced by diplodocoid and macronarian neosauropods. Taking
paleogeographical reconstructions into account, this faunal
replacement might have taken place in a surprisingly short time
interval of maximally five million years close to the end of the
Middle Jurassic.