The youngest sauropod evidence in Europe

Abstract

Titanosaur sauropods constituted one of the major dinosaur faunal components in Europe along the latest Cretaceous. Although they were abundant in the late Campanian–early Maastrichtian, titanosaurs apparently demised in terms of diversity and abundance in the late Maastrichtian Ibero-Armorican domain. Thus, any finding in this crucial period provides new clues to understand the biodiversity trend of the group prior to the K–Pg boundary. Here, we report the occurrence of a vertebral element attributed to a titanosaur in fluvial deposits dated as uppermost Maastrichtian (C29r chrone). The specimen corresponds to the right posterior part of a posterior cervical vertebra. CT-scan and histological analyses revealed high pneumatisation with laminar structures composed of compact bone, strongly remodelled with at least three generations of secondary osteons. These evidences suggest a relatively advanced age for the individual at death. Given that the partial vertebra was recovered from the uppermost portion of the late Maastrichtian, it might represent the youngest evidence for titanosaur sauropods in Europe discovered so far. Further, alongside to other remains (i.e. eggshells and footprints), the studied partial vertebra provides evidence for the persistence of this taxonomic group at the very end of the Cretaceous in southwestern Europe.