NEW REMAINS OF MACRANHINGA PARANENSIS NORIEGA (AVES, PELECANIFORMES, ANHINGIDAE) FROM THE MIOCENE OF ENTRE RIOS PROVINCE, ARGENTINA

NEW REMAINS OF MACRANHINGA PARANENSIS NORIEGA (AVES, PELECANIFORMES, ANHINGIDAE) FROM THE MIOCENE OF ENTRE RIOS PROVINCE, ARGENTINA. Macranhinga paranensis Noriega, taxon described on the basis of tarsometatarsi, is known by dissociated remains of both girdles and limb bones coming from the "Conglomerado osifero" or "Mesopotamian" at Entre Rios Province, Argentina (= base of the Ituzaingo Formation; late Miocene). In this contribution we report the first record of four isolated cervical vertebrae which are assigned to M. paranensis, coming from the Parana Formation (middle-late Miocene) at La Ensenada stream (Diamante city, Entre Rios Province) and from the "Conglomerado osifero" at La Toma Vieja fossiliferous locality (Parana city, Entre Rios Province). The systematic assignment of the new material is supported by different ratios calculated among the dimensions of vertebrae, pelvic girdles, and tarsometatarsi referred to M. paranensis, which were compared with the same proportions obtained in closed related taxa. The seventh vertebra presents several differences with that of Anhinga anhinga (Linnaeus) in the morphology of the foramen vertebrale and the facies articularis cranialis; the fifthteenth vertebra is very similar to that of M. runzii Alvarenga & Guilherme and has the zygapophysis cranialis proportionally broader and projected more posteriorly than in A. anhinga. Finally, the eighteenth vertebra has the foramen transversarium more rounded, the base of the zygapophysis caudalis with less ridged borders, and the torus dorsalis more prominent caudally than in A. anhinga. Thus, morphology, size, and metric proportions support the reference of the new materials to M. paranensis. The record of M paranensis in the Parana Formation (middle-late Miocene) extends the temporal range of this taxon.