ABSTRACT
A tibiotarsus (MACN-A 12195) collected by Ameghino in the Sarmiento Formation (Eocene–lower Miocene) outcropping in the ‘Río Chico locality’ (Chubut Province, Argentina) assigned to Diogenornis (Rheiformes, Palaeognathae), and a second limb bone (MPEF-PV 1411) from early Miocene levels of the Sarmiento Formation in Bryn Gwyn (Chubut Province, Argentina) assigned to a bird that resembles Diogenornis, were re-examined here. After a thorough comparison, we established that MACN-A 12195 corresponds to an indeterminate Palaeognathae morphologically close to Rheidae, Struthionidae, and Casuariidae, whereas MPEF-PV 1411 belongs to a Sphenisciformes, probably Palaeospheniscus. The presence of Diogenornis outside of Brazil cannot be confirmed, and therefore, its biochron and distribution area should be still restricted to the early Eocene of Itaboraí (Brazil).
Acknowledgments
To Martín Ezcurra and Agustín Martinelli (MACN), M. Encarnación Pérez and Eduardo Ruigómez (MPEF), Diego Montalti, and Yanina Herrera (MLP) for the access to the specimens under study and comparative material. We also thanks to two anonymous reviewers and the editor in chief for their helpful comments.
Disclosure statement
No potential conflict of interest was reported by the author(s).