Punatitan

Punatitan (meaning "thin atmosphere giant") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Ciénaga del Río Huaco Formation of La Rioja, Argentina. It contains one species, Punatitan coughlini.
Etymology.
The generic name "Punatitan" refers to the oxygen-depleted atmosphere characteristic of the Andes. The specific name refers to geologist Tim Coughlin, who first reported dinosaur fossils in the discovery locality.
Description.
Known from the holotype CRILAR-Pv 614 (Paleovertebrate Collection of Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja, Argentina), a partial skeleton composed of the anterior portion of posterior cervical vertebra (likely C12), two middle dorsal vertebrae (likely D6–D7), a partial sacrum, 13 articulated caudal vertebrae (some with articulated haemal arches), the right pubis, the left ischium, and several dorsal ribs, "Punatitan" was roughly long.
Classification.
The describers' phylogenetic analysis places "Punatitan" as a derived member of the Lithostrotia, in the clade Aeolosaurini, which they recover as a subclade of Rinconsauria, opposite to other analyses. Notably, "Punatitan" was recovered within a clade consisting of two species of the genus "Aeolosaurus", but the describers refrained from assigning it to said genus, instead regarding the more basal species' (""A." maximus") placement in "Aeolosaurus" dubious. However, with the reassignment of "Aeolosaurus" "maximus" to the genus "Arrudatitan" in 2021, "Punatitan"'s generic separation could be justified.
Their cladogram is shown below:
Paleoenvironment.
The holotype locality, the Quebrada de Santo Domingo site, preserves one of the largest concentrations of titanosaur eggs in the world. The describing authors suggest some connection with either "Punatitan" or its contemporary "Bravasaurus", which was described in the same paper.