A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry
Abstract
Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region.
Additional Information
© 2016 Salas-Gismondi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: October 27, 2015; Accepted: March 15, 2016; Published: April 20, 2016. We thank A. Balcarcel and W. Aguirre for fossil preparation. We are indebted to C. de Muizon and S. Bailón (MNHN); R. Hulbert, J. Bloch, B. MacFadden, and K. Krysko (UF), C. Mehling (AMNH); E. "Dino" Frey (SMNK), and R. Schoch (SMNS) for access to comparative collections; A. Valdés-Velasquez, M. Orliac, G. Billet, J. Martin, R. Lebrun, and F. Pujos for invaluable discussions; V. DeLeon for providing substantial insights on morphometric analyses and interpretation, and M. Burga for assistance in gathering data for this analysis; and P. Bona, C. Brochu, S. Jouve, T. Scheyer, and J. Moreno-Bernal for providing visual material of crocodylians. We are much indebted to C. Brochu and J. Martin for their constructive critical reviews. This is ISEM publication 2016–023 S. Author Contributions. Conceived and designed the experiments: RS-G JJF P-OA. Performed the experiments: RS-G. Analyzed the data: RS-G JJF JVT-L JC P-OA. Wrote the paper: RS-G JJF JVT-L JC P-OA. Designed the research: RS-G P-OA. Contributed to the survey and collecting the crocodylian fossil material: JJF RS-G P-OA PB JVT-L. Performed the morphometric analysis: JC RS-G. Wrote the initial draft of the manuscript, and performed anatomical descriptions and the systematic research: RS-G. Draft revisions: JJF. Additional writing and discussion: RS-G JJF PB JVT-L JC PO-A. Data Availability: All data has been collected, prepared and deposited in the Natural History Museum of the National University of San Marcos by the authors of the article. The current data is based only in fossil specimens, to which it has been assigned a specific catalog number. The catalog numbers are listed in the paper. The context information for each fossil specimen is saved in an internal database of the institution. For Museum data inquiries contact Dr. Betty Millán (bmillans@gmail.com; bmillans@unmsm.edu.pe; Director of the Natural History Museum of San Marcos) or Dr. Rodolfo Salas-Gismondi (rsalasgismondi@gmail.com; Vertebrate Paleontology Collection Manager). All other relevant data are within the paper and its Supporting Information files. The authors have declared that no competing interests existAttached Files
Published - doi-10.1371_journal.pone.0152453.pdf
Supplemental Material - pone.0152453.s001.docx
Supplemental Material - pone.0152453.s002.tif
Supplemental Material - pone.0152453.s003.tif
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Additional details
- PMCID
- PMC4838223
- Eprint ID
- 116199
- Resolver ID
- CaltechAUTHORS:20220810-751590000
- American Museum of Natural History
- Escuela Doctoral Franco-Peruana en Ciencias de la Vida
- Institut des Sciences de l'Évolution de Montpellierm (ISEM)
- Institut de recherche pour le développement (IRD)
- Ministry of Foreign Affairs (France)
- Created
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2022-08-15Created from EPrint's datestamp field
- Updated
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2022-08-15Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences
- Other Numbering System Name
- ISEM
- Other Numbering System Identifier
- 2016-023 Sud