Isthminia panamensis, a new fossil inioid (Mammalia, Cetacea) from the Chagres Formation of Panama and the evolution of ‘river dolphins’ in the Americas

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Introduction

Methods

Excavation at the type locality

Digital methods

Phylogenetic analysis

Phylogenetic nomenclature

Specimens observed

Nomenclatural acts

Results

Systematic paleontology

Description

Skull

Mandible

Dentition

Scapula

Carpals

Phylogenetic analysis

Discussion

Isthminia compared with other living and extinct inioids

Taphonomy, body size, and ecomorphology

Environmental and ecological implications

The evolutionary history of inioidea in the Americas

Supplemental Information

Collecting the type specimen of Isthminia at the type locality on 18 June 2011.

(A) The specimen exposed in the outcrop, at low tide, with the scapula, oriented lateral side facing stratigraphic up, approximately 35 cm away from the skull, which was exposed ventral side up. Scale bar = 10 cm. Photo: J. Velez-Juarbe. (B) With the high tide returning, removal of the plaster jacketed sediment block, containing the skull, exposed the mandibles located directly underneath it. The mandible was oriented dorsal surface facing stratigraphic up. Photo: A. O’Dea.

DOI: 10.7717/peerj.1227/supp-1

File S2

Otolith data collected by Orangel Aguilera from the Chagres Formation.

DOI: 10.7717/peerj.1227/supp-3

Supplemental Video 1

CT movie though the skull Isthminia panamensis, using a stack of DICOM images, processed in ImageJ (v. 1.48), oriented dorsal to image top, right lateral to the image right, and left lateral to image left. Original CT data are available at Smithsonian X 3D (http://3d.si.edu).

DOI: 10.7717/peerj.1227/supp-4

Additional Information and Declarations

Competing Interests

Nicholas D. Pyenson is an Academic Editor for PeerJ.

Author Contributions

Nicholas D. Pyenson, Jorge Vélez-Juarbe, Carolina S. Gutstein and Aaron O’Dea conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Holly Little performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Dioselina Vigil conceived and designed the experiments, performed the experiments, reviewed drafts of the paper.

Field Study Permissions

The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):

Fossil material was collected and exported under the Government of the Republic of Panama’s Ministerio de Comercio e Industrias (MICI number DNRM-MC-074-11).

Data Availability

The following information was supplied regarding the deposition of related data:

Full resolution 3D models and original CT data are available online at Smithsonian X 3D (http://3d.si.edu) and archived, along with supplemental data, in Zenodo (https://zenodo.org/record/27214) at the following DOI: 10.5281/zenodo.27214.

New Species Registration

The following information was supplied regarding the registration of a newly described species:

Isthminia

urn:lsid:zoobank.org:act:83F6A9B4-289D-45DE-A3D1- C361DAAAF973

Isthminia panamensis

urn:lsid:zoobank.org:act:A5C706B6-E0B6-43E5-A65C-E6FE0B2BDF1A.

Funding

The research of NDP was funded by the Smithsonian Institution, its Remington Kellogg Fund, and with support from the Basis Foundation. This project was also partially funded by an NSF EAR Postdoctoral Fellowship (1249920) to JVJ and NSF PIRE (0966884). Funding from CONICYT, Becas Chile, Departamento de Postgrado y Postítulo of the Vicerrectoría de Asuntos Académicos of Universidad de Chile supported CSG. This research was also supported financially by the National System of Investigators (SNI) of the National Secretariat for Science, Technology and Innovation of Panama (SENACYT) and a NSF Collaborative Research award (1325379) to AO. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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