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Eocene caviomorph rodents from Balsayacu (Peruvian Amazonia)

Boivin, Myriam and Marivaux, Laurent and Aguirre-Diaz, Walter and Andriolli Custódio, Michele and Benites-Palomino, Aldo and Pujos, François and Roddaz, Martin and Salas-Gismondi, Rodolfo and Stutz, Narla and Tejada-Lara, Julia V. and Yans, Johan and Antoine, Pierre-Olivier (2022) Eocene caviomorph rodents from Balsayacu (Peruvian Amazonia). PalZ, 96 (1). pp. 135-160. ISSN 0031-0220. doi:10.1007/s12542-021-00551-0.

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The Paleogene record of caviomorph rodents has substantially increased over the last decades, and their evolutionary history better understood by the discovery of their earliest representatives, so far recorded in several pre-Deseadan localities in Peruvian Amazonia. We report here the discovery of new caviomorph fossils from the Balsayacu area in Peru (TAR-55/TAR-55bis, TAR-76 and TAR-77 localities, San Martín Department). The study of this new material reveals the occurrence of four caviomorph taxa in these localities: Balsayacuy huallagaensis gen. et sp. nov., Chachapoyamys kathetos gen. et sp. nov. and Caviomorpha gen. et sp. indet. 1 and 2. It allows the revision and refinement of taxonomic assignments of previously described specimens. The first three taxa have a primitive dental pattern, as that characterizing stem Caviomorpha recorded in pre-Deseadan localities of Peru (Eocene localities of Contamana and ?late Eocene/early Oligocene Santa Rosa). We support here an Eocene age for the Balsayacu section due to the complete absence of morphologically derived taxa representing modern caviomorph superfamilies. By the presence of derived characters in Balsayacuy and Chachapoyamys compared to Canaanimys maquiensis and Cachiyacuy contamanensis from CTA-27 (Contamana, Peru; late middle Eocene), the Balsayacu section may document a time interval slightly younger than CTA-27 (which further yields Chachapoyamys cf. kathetos) and older than those of Santa Rosa and Tarapoto-Shapaja, likely documenting latest middle or early late Eocene times. These low-latitude stem caviomorph faunas provide new insights into the early evolutionary history and paleodiversity of that group immediately before the rise of modern superfamilies.

Item Type:Article
Related URLs:
URLURL TypeDescription Information Information
Boivin, Myriam0000-0002-5240-9460
Marivaux, Laurent0000-0002-2882-0874
Andriolli Custódio, Michele0000-0002-3543-8278
Benites-Palomino, Aldo0000-0002-5409-6322
Pujos, François0000-0002-6267-3927
Roddaz, Martin0000-0001-8562-8582
Salas-Gismondi, Rodolfo0000-0001-9990-8841
Stutz, Narla0000-0002-1937-3902
Tejada-Lara, Julia V.0000-0003-2307-6764
Yans, Johan0000-0001-7590-0298
Antoine, Pierre-Olivier0000-0001-9122-1818
Additional Information:© 2022 Springer Nature. Received 17 August 2020. Accepted 08 February 2021. Published 03 June 2021. Many thanks to all the people that helped us in the field and in the lab. We are particularly grateful to our drivers Giancarlo, Manuel, and Percy, for their long-standing help during the yearly field seasons in the San Martín Department of Peruvian Amazonia. We warmly thank A. Assemat (ISEM, Montpellier, France) for taking SEM photographs of the original specimens from TAR-55/TAR-55bis collected in 2015–2016; C. Cazeveille (Montpellier RIO Imaging, Institut des Neurosciences de Montpellier, France) for access to a scanning electron microscope facility; and C. Girard (ISEM) for access to her optical stereomicroscope facility. We are indebted to A.-L. Charruault and S. Jiquel (ISEM) for the cast preparation of the rodent material from the Balsayacu section and from other Peruvian localities. We also thank the Editors of the PalZ. Paläontologische Zeitschrift, Thomas Mörs and Mike Reich, as well as M. Arnal (MLP, La Plata, Argentina) and A. Kramarz (MACN, Buenos Aires, Argentina), who provided formal reviews of this manuscript that enhanced the final version. This work was supported by The Leakey Foundation, the National Geographic Society, the “Investissements d’Avenir” grant managed by the “Agence Nationale de la Recherche” (CEBA, ANR-10-LABX-25-01), and by the COOPINTEER CNRS/CONICET (n° 252540) and the ECOS-SUD/FONCyT (n° A-14U01) international collaboration programs. This work was carried out in the frame of the ongoing cooperation agreement between the “Museo de Historia Natural de la Universidad Nacional Mayor San Marcos” (Lima, Peru) and the “Institut des Sciences de l’Évolution de Montpellier-Université de Montpellier” (France). This is ISEM publication 2021-032-Sud.
Funding AgencyGrant Number
Leakey FoundationUNSPECIFIED
National Geographic SocietyUNSPECIFIED
Agence Nationale de la Recherche (ANR)ANR-10-LABX-25-01
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)252540
Fondo para la Investigación Científica y Tecnológica (FONCYT)A-14U01
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Subject Keywords:Rodentia; Systematics; Biostratigraphy; Peru; South America
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Issue or Number:1
Record Number:CaltechAUTHORS:20220810-732982000
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Official Citation:Boivin, M., Marivaux, L., Aguirre-Diaz, W. et al. Eocene caviomorph rodents from Balsayacu (Peruvian Amazonia). PalZ 96, 135–160 (2022).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116213
Deposited By: George Porter
Deposited On:12 Aug 2022 20:44
Last Modified:12 Aug 2022 20:44

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