Pellegrinisaurus

Pellegrinisaurus (meaning "Lizard from Pelligrini") is a genus of titanosaurian sauropod dinosaur that lived in South America during the Late Cretaceous period. The holotype was found in the Allen Formation, Argentina.
Discovery and naming.
The assigned holotype, MPCA 1500, was discovered in 1975 by Roberto Abel and his assistant Jaime Emilio Powell. It was recovered from the lower member of the Allen Formation in the locality of Pellegrini Lake, Argentina, dating from the Late Cretaceous, Campanian to lower Maastrichtian, but it was not formally described until 1996 by Leonardo Salgado. Initially, the recovered remains were referred to "Epachthosaurus", but later this hypothesis was abandoned because MPCA 1500 did not share derived features with the holotype of "Epachthosaurus". The generic name "Pellegrinisaurus" refers to Pellegrini Lake, where the specimen was found. The specific name "powelli" is in honour of Jaime E. Powell.
Description.
"Pellegrinisaurus" is a rather large titanosaur. The estimated body size is about . The holotype includes an incomplete right femur, twenty-six caudal and four dorsal vertebrae. Autapomorphic features of "Pellegrinisaurus", by which it can be distinguished, are:
"Pellegrinisaurus" differs from other titanosaurs by having anteroposteriorly elongate and dorsoventrally depressed mid-posterior and posterior caudal spines; Salgado interpreted this condition as an extra-articulation between the neural spine and the articular process of the subsequent vertebra, that reduced tail movement.
The right femur is partially preserved. It is anteroposteriously compressed with a very flattened fourth trochanter. Laterally, it features a pronounced bulge similar to that of "Chubutisaurus", brachiosaurids and other titanosaurs.
Paleoecology.
"Pellegrinisaurus" was unearthed from the Allen Formation, in which it probably lived alongside other titanosaurs, such as "Aeolosaurus" and "Rocasaurus". Salgado suggested that contemporaneous hadrosaurids and the titanosaur "Aeolosaurus" inhabited coastal lowlands while other larger titanosaurs (such as "Pellegrinisaurus") and theropods inhabited interior environments of the region.
Classification.
Initially, Salgado placed "Pellegrinisaurus" as a possible sister taxon of the Saltasaurinae, in view of the build of its vertebrae.
Later, during the description of "Mansourasaurus", Sallam "et al." (2017) published a complete phylogenetic analysis of the Titanosauria in which "Pellegrinisaurus" is found to be part of the clade Lithostrotia, in the Opisthocoelicaudiinae.