Pablo Ariel Gallina and Alejandro Otero
The original material
assigned to Laplatasaurus araukanicus Huene come from five different localities
in northern Patagonia (Argentina) where the Upper Cretaceous (Campanian) lies
exposed. This material includes several postcranial bones from multiple
specimens and showing different conditions of preservation, often lacking
anatomical overlap. The taxonomic status of the taxon is further obscured by
the absence of quarry maps of the multiple localities (lacking the recognition
of associated materials), and a proper designation of type material in its
original description. After Huene, new material was assigned to this taxon,
although none of it resolved the existing taxonomic issues. In 1979, the
designation of a lectotype (one tibia and one fibula) was the first stage in
the nomenclatural stabilization of the species. However, the assignment of the
remaining material to L. araukanicus remained uncertain. Here we review all the
material hitherto assigned to this taxon in order to clarify its taxonomic
status. We also provide a re-description of the lectotype and discuss the taxonomic
identification of material previously referred to this taxon. Lastly we include
it for the first time in an updated phylogenetic data matrix. Laplatasaurus
araukanicus is retained only for the lectotype. The material from Rancho de
Ávila is referred to cf. Bonitasaura sp. because they share diagnostic features
and are stratigraphically congruent. The remaining material is referred as
Lithostrotia indet. A phylogenetic analysis nests Laplatasaurus within Titanosauria
in a clade formed by ((Laplatasaurus + Uberabatitan) + (Bonitasaura +
(Futalognkosaurus + Mendozasaurus))).
Gallina, P. A. and
Otero, A. 2015. Reassessment of Laplatasaurus
araukanicus (Sauropoda: Titanosauria) from the Upper Cretaceous of
Patagonia, Argentina. Ameghiniana 52(5): 487-501.
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