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Laplatasaurus (titanosaur from Late Cretaceous of Argentina) reassessed

Ben Creisler

A new online paper:

Pablo A. Gallina & Alejandro Otero (2015)
Reassessment of Laplatasaurus araukanicus (SAUROPODA: TITANOSAURIA),
from the Late Cretaceous of Patagonia, Argentina.
Ameghiniana (advance online publication)

The original materials assigned to Laplatasaurus araukanicus Huene
1929 come from five different localities from the Upper Cretaceous
(Campanian) of northern Patagonia, Argentina. These include several
postcranial bones from multiple specimens and different conditions of
preservation, often lacking anatomical overlap. The taxonomic status
of the taxon is made worse by the absence of quarry maps from any of
the multiple localities (lacking the recognition of associated
materials), and a proper designation of type materials in its original
description. After Huene, several new materials were assigned to this
taxon, although these did not resolve the existing taxonomic problems.
In 1979, the designation of a lectotype material (one tibia and one
fibula) was the first stage for the establishment of the taxon
validity and constituency. However, the validity of the remaining
materials assigned to Laplatasaurus remained unresolved. Here, we
review all the materials that have hitherto been assigned to this
taxon in order to establish a proper systematic status, to provide a
re-description of the lectotype, to discuss the taxonomic
identification of materials previously referred to this taxon, and to
include it into an updated phylogenetic data matrix for the first
time. Laplatasaurus araukanicus Huene 1929 is retained only for the
lectotype material. The materials from Rancho de Ávila are referred to
cf. Bonitasaura sp. by both presence of shared diagnostic features and
stratigraphic congruence . The remaining materials are referred as
Lithostrotia indet. A phylogenetic analysis nests Laplatasaurus within
Titanosauria in a clade formed by ((Laplatasaurus + Uberabatitan) +
(Bonitasaura + (Futalognkosaurus + Mendozasaurus)).