Systematic status of the Miocene darter ‘Liptornis’ hesternus Ameghino, 1895 (Aves, Suliformes, Anhingidae) from Patagonia, Argentina

Abstract

Diederle, J.M., 1.8.2015. Systematic status of the Miocene darter ‘Liptornis’ hesternus Ameghino, 1895 (Aves, Suliformes, Anhingidae) from Patagonia, Argentina. Alcheringa 39, 589–594. ISSN 0311-5518.

Liptornis hesternus was established by Ameghino in the late 1800s on the basis of a cervical vertebra (NHMUK-A599) from the Santa Cruz Formation (Santacrucian, South American Land Mammal Age, early Miocene, Burdigalian Stage) of Patagonia, Argentina. Although taxonomic attributions were controversial, the specimen is now confidently assigned to Anhingidae. Recently, however, L. hesternus was designated a nomen dubium because of its uninformative diagnostic characters and apparent loss of the holotype. Nevertheless, NHMUK-A599 has been relocated and is redescribed here prompting referral to Anhinga. A combination of traits are shared with the extant Anhinga anhinga and A. melanogaster, and the material is dimensionally compatible with A. anhinga. The estimated body size of NHMUK-A599 would have been larger than A. minuta but less than A. grandis, A. subvolans, A. fraileyi and A. walterbolesi. Finally, Anhinga hesterna is considered valid and represents the stratigraphically oldest occurrence of the genus in South America and the southernmost yet recorded.

Juan M. Diederle [[email protected]], Laboratorio de Paleontología de Vertebrados, Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción (CICYTTP-CONICET), Materi y España, E3105BWA Diamante, Entre Ríos, Argentina.

Key words:

• Anhinga
• Neogene
• Santa Cruz Formation
• Santacrucian
• South America

Acknowledgements

The author thanks Dr Jorge Noriega for his corrections, suggestions, and for providing the photographs of the material studied. Dr Carolina Acosta Hospitaleche, Dr Diego Brandoni and Dr Flavio Góis Lima provided corrections and comments. Dr Martjan Lammertink and Mrs Elizabet Diederle for their corrections in the translation to English. Dr Pablo Tubaro (MACN), Dr Cecilia Kopuchian (MACN) and Dr Herculano Alvarenga (MHNT) facilitated access to osteological collections of birds. The author also thanks the editor Dr Stephen McLoughlin and the assistant editor Dr Ben Kear for their comments and suggestions. Finally, the author thanks Marcos Cenizo and an anonymous reviewer for their important comments on this manuscript. This study was supported by CONICET (Argentina).