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

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

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2021

0195-6671

Pellegrinisaurus powelli is a large titanosaurian sauropod from the Upper Cretaceous of northern Patagonia(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 to Pellegrinisaurus. 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 of Pellegrinisaurus,reviewing its diagnosis and phylogenetic position. A histological analysis of the femur of the holotype isalso carried out. The diagnostic characters originally proposed for Pellegrinisaurus are 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 recovers Pellegrinisaurus as a non-saltasaurid lithostrotian, closelyrelated with Alamosaurus sanjuanensis. The bone histology indicates that the holotype corresponds to asubadult (i.e. sexually mature but still growing) individual. Finally, the caudal vertebra previouslyattributed to Pellegrinisaurus cannot be referred to this genus and is here assigned to Titanosauria indet.