About the alleged record of the Rheidae Diogenornis in the Cenozoic of Argentina: new interpretations

ACOSTA HOSPITALECHE, CAROLINA; PICASSO M.B.J

Historical Biology

Taylor and Francis

Año: 2022

0891-2963

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 SarmientoFormation in Bryn Gwyn (Chubut Province, Argentina) assigned to a bird that resembles Diogenornis, werere-examined here. After a thorough comparison, we established that MACN-A 12195 corresponds to anindeterminate Palaeognathae morphologically close to Rheidae, Struthionidae, and Casuariidae, whereasMPEF-PV 1411 belongs to a Sphenisciformes, probably Palaeospheniscus. The presence of Diogenornisoutside of Brazil cannot be confirmed, and therefore, its biochron and distribution area should be stillrestricted to the early Eocene of Itaboraí (Brazil).