The largest freshwater odontocete: A South Asian river dolphin relative from the proto-Amazonia

Creators: Benites-Palomino, Aldo; Aguirre-Fernández, Gabriel; Baby, Patrice; Ochoa, Diana; Altamirano, Ali; Flynn, John J.; Sánchez-Villagra, Marcelo R.; Tejada, Julia V.¹; de Muizon, Christian; Salas-Gismondi, Rodolfo

1. California Institute of Technology

Abstract

Several dolphin lineages have independently invaded freshwater systems. Among these, the evolution of the South Asian river dolphin Platanista and its relatives (Platanistidae) remains virtually unknown as fossils are scarce. Here, we describe Pebanista yacuruna gen. et sp. nov., a dolphin from the Miocene proto-Amazonia of Peru, recovered in phylogenies as the closest relative of Platanista. Morphological characters such as an elongated rostrum and large supraorbital crests, along with ecological interpretations, indicate that this odontocete was fully adapted to fresh waters. Pebanista constitutes the largest freshwater odontocete known, with an estimated body length of 3 meters, highlighting the ample resource availability and biotic diversity in the region, during the Early to Middle Miocene. The finding of Pebanista in proto-Amazonian layers attests that platanistids ventured into freshwater ecosystems not only in South Asia but also in South America, before the modern Amazon River dolphin, during a crucial moment for the Amazonian evolution.

Copyright and License

© 2024 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).

https://creativecommons.org/licenses/by/4.0/

Acknowledgement

We extend our gratitude to O. Lambert (IRSNB), M. Viglino (CONICET), and G. Bianucci (U. Pisa) for helpful comments on the record of river dolphins. We express our immense gratitude to the communities of Santa Clotilde and Tacshacuraray for generosity and hospitality during our 2018 field expedition, as well as to our local guide M. Valles for constant support during our palaeontological expeditions in the Peruvian Amazonia.

Funding

This research was supported by funds to A.B.-P. by the UZH Candoc Grant (FK-22-082) and to M.R.S.-V. by the Swiss National Science Foundation (SNSF-SPIRIT IZSTZ0-208545). The field expedition that led to the discovery of the holotype specimen Pebanista was funded by the National Geographic Explorers Grant to R.S.-G. (#CP-035R-17) and the Frick Fund (AMNH) to J.J.F. We also extend our gratitude to the editorial team of Science Advances and the reviewers who greatly improved the quality of this contribution.

Contributions

Conceptualization: A.B.-P., G.A.-F., and R.S.-G. Methodology: A.B.-P., G.A.-F., D.O., M.R.S.-V., and R.S.-G. Investigation: A.B.-P., G.A.-F., P.B., D.O., A.A., J.J.F., M.R.S.-V., J.V.T., C.d.M., and R.S.-G. Visualization: A.B.-P., G.A.-F., J.J.F., C.d.M., and R.S.-G. Supervision: A.B.-P., G.A.-F., M.R.S.-V., and R.S.-G. Writing—original draft: A.B.-P. and G.A.-F. Writing—review and editing: A.B.-P., G.A.-F., P.B., D.O., A.A., J.J.F., M.R.S.-V., J.V.T., C.d.M., and R.S.-G.

Data Availability

All data are available as supplementary materials. An additional dataset has been available via Dryad at: https://doi.org/10.5061/dryad.v41ns1s3t. The surface 3D model (.ply) of the holotype specimen of Pebanista yacuruna gen et sp. nov. has been made available via Morphomuseum and can be freely accessed at: https://doi.org/10.18563/journal.m3.221. Nomenclatural acts have been formally deposited in Zoobank, under the following LSID: urn:lsid:zoobank.org:act:580F4BD2-9AB5-49C7-B7F4-F4068EF0E9C0.

Conflict of Interest

The authors declare that they have no competing interests.

Name	Size	Download all
sciadv.adk6320.pdf md5:abe1cb64759fbb05df034e93866dcf60	7.2 MB	Preview Download
sciadv.adk6320_sm.pdf md5:3d5864b298f207eed6f31e52f72ec163	7.9 MB	Preview Download

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes