Journal of Mammalian Evolution

, Volume 26, Issue 1, pp 85–100 | Cite as

Virtual Endocast Morphology of Mesotheriidae (Mammalia, Notoungulata, Typotheria): New Insights and Implications on Notoungulate Encephalization and Brain Evolution

  • Marcos Fernández-MonescilloEmail author
  • Pierre-Olivier Antoine
  • François Pujos
  • Helder Gomes Rodrigues
  • Bernardino Mamani Quispe
  • Maeva Orliac
Original Paper


We provide morphological, quantitative, and qualitative studies of cranial endocasts of mesotheriid notoungulates solving previous open debate on notoungulate endocasts. For that purpose, we use the most accurate digital reconstructions methods. We confirm that mesotheriids have endocasts similar in shape and gyrification to those of other rodent-like notoungulates (i.e., Hegetotheriidae and Interatheriidae) and living cavy rodents (e.g., Dolicavia minuscula, Hydrochoerus, and Cavia). We identify these similarities as evolutionary response to potentially similar ecological constraints. Based on the encephalization quotient (EQ) of several notoungulate families (i.e., Mesotheriidae, Interatheriidae, Notohippidae, Toxodontiidae, and Hegetotheriidae), there seems to be no increase in terms of EQ or neocortical complexity through time in that group. In addition, comparison with several Holarctic ‘euungulates’ leads us to propose differential predation pressure as a potential driver for EQ. Among notoungulates, braincase comparison between well-known Oligocene–Pleistocene mesotheriids and other families identifies lifestyle as an additional possible driver for EQ, with lower values for semifossorial taxa, in a similar way to rodents. Finally, the observed stability of mesotheriid EQ (from the Oligocene to the Pliocene) would match a conservative lifestyle further reflected by their highly invariant appendicular skeleton.


South America Bolivian Altiplano Paleomammalogy Paleoneurology Computed tomography (CT) Digital cranial endocast Ungulate brains Stasis 



We acknowledge A. Kramarz and S. Alvarez (MACN, Buenos Aires, Argentina), C. de Muizon, C. Argot, and G. Billet (MNHN, Paris, France), and A. De Sosa Tomas (UNPSJB, Comodoro Rivadavia, Argentina) who gave access to the specimens under they care.

We kindly thank all the team members: M. A. Abello, S. Adnet, G. Billet, L. Marivaux, M. B. Prámparo, P. Münch, and R. Andrade Flores who participated in the field missions in Achiri (2010–2015). We also acknowledge staff from the UMS2700 OMSI (MNHN, Paris) for having given access to their X-ray microtomography facilities (AST-RX platform). Finally, we warmly thank S. Mosconi from the Fundación Escuela Medicina Nuclear (Mendoza, Argentina), M. Namias from the Fundación Centro Diagnóstico Nuclear (Buenos Aires, Argentina), and the personnel from MEDICENTRO clinic (La Paz, Bolivia) for providing access to CT scanner facilities. We are grateful to the people of Achiri for facilitating our fieldwork (2010–2015). This work was notably funded by the ECOS-FonCyT program (A14U01) and the National Geographic Society (NGS 9971-16). This project was made possible thanks to the cooperation agreement between the MNHN Bol, the IANIGLA, and the ISEM (CONICET Cooperation Agreement N°864/2014). This work was also supported by the LabEx BCDiv (Laboratoire d’Excellence Biological and Cultural Diversities,

Finally, we thank Dr. John Wible, and the reviewers Dr. Darin Croft and one anonymous for their helpful and constructive comments on an earlier version of this paper.

Supplementary material

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Copyright information

© Springer Science+Business Media, LLC 2017

Authors and Affiliations

  • Marcos Fernández-Monescillo
    • 1
    Email author
  • Pierre-Olivier Antoine
    • 2
  • François Pujos
    • 1
  • Helder Gomes Rodrigues
    • 3
    • 4
  • Bernardino Mamani Quispe
    • 5
  • Maeva Orliac
    • 2
  1. 1.Instituto Argentino de Nivología Glaciología y Ciencias Ambientales (IANIGLA)CCT–CONICET–MendozaMendozaArgentina
  2. 2.Institut des Sciences de l’Evolution, cc64Université de Montpellier, CNRS, IRD, EPHEMontpellierFrance
  3. 3.Department of Origines et évolutionsSorbonne Universités, CR2P, UMR CNRS 7207ParisFrance
  4. 4.Mécanismes adaptatifs et évolution (MECADEV), UMR 7179, CNRS, Funevol teamMuséum National d’Histoire NaturelleParis Cedex 5France
  5. 5.Departamento de PaleontologíaMuseo Nacional de Historia NaturalLa PazBolivia

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