Osteology, paleohistology and phylogenetic relationships of Pellegrinisaurus powelli (Dinosauria: Sauropoda) from the Upper Cretaceous of Argentinean Patagonia

CERDA, IGNACIO; ZURRIAGUZ, VIRGINIA LAURA; CARBALLIDO, JOSÉ LUIS; GONZÁLEZ, ROMINA; SALGADO, LEONARDO

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2021 vol. 128

0195-6671

Pellegrinisaurus powelliis a large titanosaurian sauropod from the Upper Cretaceous of northern Pata-gonia (Río Negro Province, Argentina). The holotype of this species comprises an incomplete femur, fourdorsal and 26 caudal vertebrae collected from the Lago Pellegrini locality. A single middle caudal vertebrafrom the nearby Cinco Saltos locality has been more recently referred toPellegrinisaurus. With thepurpose of increasing our knowledge about the titanosaur faunas of the Upper Cretaceous of Patagonia,here we provide a detailed redescription of the holotype and referred specimens ofPellegrinisaurus,reviewing its diagnosis and phylogenetic position. A histological analysis of the femur of the holotype isalso carried out. The diagnostic characters originally proposed forPellegrinisaurusare here consideredinvalid because they either correspond with diagenetic deformations of the specimen or are present inother titanosaurs. The new diagnostic features are related with the presence of large lateral blind fossaewith distinct dorsal rims in the anterior caudal centra and with a low longitudinal ridge on the posteriorside of the femur shaft originated from the trochanteric shelf and extending to the distal third of theshaft. The phylogenetic analysis recoversPellegrinisaurusas a non-saltasaurid lithostrotian, closelyrelated withAlamosaurus sanjuanensis. The bone histology indicates that the holotype corresponds to asubadult (i.e. sexually mature but still growing) individual. Finally, the caudal vertebra previouslyattributed toPellegrinisauruscannot be referred to this genus and is here assigned to Titanosauria indet.