On a dicraeosaurid specimen from the Mulichinco Formation (Valanginian, Neuquén Basin) of Argentina and phylogenetic relationships of the South American dicraeosaurids (Sauropoda, Diplodocoidea)

Guillermo J. WINDHOLZ, Rodolfo A. CORIA, Flavio BELLARDINI, Mattia A. BAIANO, Diego PINO, Francisco ORTEGA & Philip J. CURRIE

en Comptes Rendus Palevol 21 (45) - Pages 991-1019

Published on 21 December 2022

The osteology of Pilmatueia faundezi Coria, Windholz, Ortega & Currie, 2019, a dicraeosaurid sauropod from the Lower Cretaceous of Patagonia, is reassessed from the perspective of a new specimen (MLL-Pv-010) that provides additional information on the axial skeleton and the pectoral girdle. The specimen MLL-Pv-010 is composed of three articulated anterior-middle cervical vertebrae (with their respective ribs in position and an associated fourth rib), seven dorsal vertebrae with associated dorsal ribs, a distal caudal vertebra, a left scapula and the proximal end of a right scapula. The new specimen shows features, especially in the middle cervical vertebrae, that link it to Pilmatueia faundezi. Additionally, the specimen MLL-Pv-010 shows features previously unknown for the species, such as the morphology and orientation of the bifid neural spines of the anterior and mid-cervical vertebrae. The information obtained from the specimen MLL-Pv-010 allows us to propose an expanded diagnosis of Pilmatueia faundezi. Moreover, two phylogenetic analyses focusing on South American dicraeosaurids show that Pilmatueia Coria, Windholz, Ortega & Currie, 2019 is well nested within Dicraeosauridae Huene, 1927. One of our phylogenetic hypotheses differs from previous contributions in showing South American dicraeosaurids as a monophyletic group. However, in the second hypothesis these are not recovered as a natural group. We think that it is reasonable to recover a South American dicraeosaurid clade, and that eventually it will be best supported once more evidence is recovered.


Sauropoda, Dicraeosauridae, Pilmatueia faundezi, Lower Cretaceous, Mulichinco Formation, new specimen

Download full article in PDF format Order a reprint