A late Eocene frog assemblage from the Geste Formation, Puna of north-western Argentina

ABSTRACT

Frogs (Anura) are major components of tetrapod communities in the Neotropics and, according to divergence-time estimates, were already diverse in early Palaeogene times, but this is still poorly documented in the fossil record. A late Eocene frog assemblage from the Geste Formation exposed at Antofagasta de la Sierra (Catamarca province) is here described, providing a first glimpse into the Palaeogene anuran diversity in the present-day Puna of north-western Argentina. The assemblage is composed by at least four hyloid neobatrachian taxa having miniature to large body-sizes, ranging 17–81 mm estimated snout-vent length. Neither the families currently found in the Puna-Altiplano, nor those from the Cretaceous – Eocene of southern South America, are represented. The assemblage comprises possible brachycephaloids, odontophrynids, and hemiphractids, suggesting climatic and environmental conditions very different from the harsh conditions prevailing today in the Puna-Altiplano and a biogeographical link with Amazonia. The joint presence of these taxa is currently restricted to the nearby Austral Yungas and the Atlantic Forest, suggesting that the late Eocene frogs likely inhabited a humid forest. The new frog assemblage constitutes a rare window to the early evolution of Neotropical anurans and a major leap forward in the palaeoenvironmental reconstruction of the Puna during Eocene times.

KEYWORDS:

• Anura
• frog assemblage
• Eocene
• Geste Formation
• Puna
• Neotropics

Acknowledgments

We deeply thank Lucas Soriano, head of the “Casa de Ganadería” who kindly contributed to our fieldwork in Antofagasta de la Sierra. We also thank Guadalupe Saadi and Carlos Palacios from the Departamento de Comunidades de Altura (Catamarca province). Luis Fonseca and Sergio Álvarez (Dirección Provincial de Antropología, Catamarca, Argentina) for granting exploration permits. Other field trip facilities were arranged by INSUGEO. We also want to thank former students that collaborate with picking techniques: F. Deforel, L. Garnier, G. Ortiz, L. Saade, A.S. Dip, E. Grimaldi, O. Saguir, L. Vaquera, L. Sosa, M. Navarro, B. Pérez, G. Posadino, A. Figueroa, J. Astrada J., F. Frohlich. Thanks are extended to two anonymous reviewers and the Editor in Chief G. Dyke. We acknowledge the continued support of Universidad de Buenos Aires, Fundación/Instituto Miguel Lillo, and CONICET.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Institutional abbreviations

AMNH: American Museum of Natural History, New York, USA; BAR: Museo Paleontológico de San Carlos de Bariloche, San Carlos de Bariloche, Argentina; CAS: California Academy of Sciences, San Francisco, USA; CFA: CEBBAD-Fundación Félix de Azara, Buenos Aires, Argentina; CJ: Museo del Centro Jambatu, Centro Jambatu de Investigación y Conservación de Anfibios, Quito, Ecuador; CM: Carnegie Museum of Natural History, Pittsburgh, USA; CPBA: Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina; FCEN: Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina; FML: Instituto de Herpetología de la Fundación Miguel Lillo, San Miguel de Tucumán, Argentina; FMNH: Field Museum of Natural History, Chicago, USA; KU: Biodiversity Institute, University of Kansas, Lawrence, USA; LACM: Natural History Museum of Los Angeles County, Los Angeles, USA; MACN: Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Buenos Aires, Argentina; MCZ: Museum of Comparative Zoology, Harvard University, Harvard, USA; MHNCI: Museu de História Natural Capão da Imbuia, Curitiba, Brazil; MLP: Museo de La Plata, La Plata, Argentina; MNHN: Muséum National d’Histoire Naturelle, Paris, France; MPEF: Museo Paleontologico ‘Egidio Feruglio’, Trelew, Chubut, Argentina; MVZ: Museum of Vertebrate Zoology, University of California, Berkeley, USA; NHMW: Naturhistorisches Museum Wien, Vienna, Austria; RBINS: Royal Belgian Institute of Natural Sciences, Brussels, Belgium; UF: University of Florida, Florida Museum of Natural History, Gainesville, USA; USNM: National Museum of Natural History, Washington, USA; YPM: Yale Peabody Museum, Yale University, New Haven, USA; ZSM: Bavarian State Collection, Munich, Germany.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08912963.2024.2322532

Additional information

Funding

This study was supported by Fundación Miguel Lillo [CUP G-0035-1], [PIP 778], [PICT 2020–3651].