The appendicular osteology of Patagotitan mayorum (Dinosauria, Sauropoda)

OTERO, A.; CARBALLIDO J. L.; PÉREZ MORENO, A.

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2020

0272-4634

Its huge size, excellent preservation and completeness make Patagotitan mayorum a unique opportunity to explore the anatomy, paleobiological and phylogenetic aspects linked to gigantism within Sauropoda. In this regard, we describe the appendicular skeleton of this titanosaurian species that lived in the late Albian (Cerro Barcino Formation), Chubut Province, Argentina. The diagnosis of Patagotitan mayorum is revised, increasing the number of identified autapomorphies (i.e., lateral surface of the scapular blade with two divergent crests; anterior surface of proximal humerus with paired muscle scars; combined bulges on the deltopectoral area of the humerus; ischium with well-developed and sharp ridge projecting from the ischial tuberosity to the distal blade). Several diagnostic characters of this species correspond to osteological correlates associated to appendicular musculature (e.g., Mm. deltoideus scapularis, deltoideus clavicularis and teres major; M. coracobrachialis; Mm. supracoracoideus/deltoideus clavicularis and latissimus dorsi; Mm. flexor tibialis 3 and adductor femoris 2), here being discussed in the context of sauropod evolution. Finally, in the light of a modification of the scaling equation previously proposed and adjusting the long bone circumference for the humeri of Patagotitan, the new body mass estimate of this species ranges between 42?71 tons, with a mean value of 57 tons. Although considerably less than the value obtained by the linear equation originally used, the corrected quadratic equation used here provides a mean body mass estimate that is more consistent with those derived from volumetric reconstructions of Patagotitan.