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New Katepensaurus (sauropod) material from Cretaceous of Argentina

Ben Creisler

A new online paper:

Lucio M. Ibiricu, Gabriel A. Casal, Rubén D. Martinez, Matthew C.
Lamanna, Marcelo Luna & Leonardo Salgado (2015)
New material of Katepensaurus goicoecheai (SAUROPODA: DIPLODOCOIDEA)
and its significance for the morphology and evolution of
Ameghiniana (advance online publication)

Cretaceous outcrops in southern South America preserve a rich and
evolutionarily important record of sauropod dinosaurs. Within
Sauropoda, South American titanosaurs have garnered particular
interest due to their abundance and taxonomic diversity. Nevertheless,
the fossil record of rebbachisaurids has also improved significantly
in recent years, and therefore so has knowledge of the group. However,
many aspects of the anatomy and phylogenetic relationships of
Rebbachisauridae remain unresolved, due in large part to the
fragmentary nature of many members of the clade. Within this context,
we describe new fossils of Katepensaurus goicoecheai Ibiricu, Casal,
Martínez, Lamanna, Luna, and Salgado, a recently-named rebbachisaurid
from the Upper Cretaceous (Cenomanian/Turonian) Bajo Barreal Formation
of central Patagonia (Argentina). Based on these additional materials,
we propose two new autapomorphies of this taxon: (1) ventral portion
of posterior articular surface of anterior dorsal vertebral centrum
wider than dorsal portion, conferring a ‘teardrop-shaped’ contour; and
(2) ovoid fossa on dorsal aspect of anterior to middle dorsal
vertebral transverse processes. These features enhance our
understanding of morphological diversity within Rebbachisauridae and
augment the diagnosis of Katepensaurus. Furthermore, phylogenetic
analysis confirms the assignment of this taxon to the rebbachisaurid
subclade Limaysaurinae. Katepensaurus is the southernmost record of a
rebbachisaurid that is identifiable to the generic level.