The Science of Nature

, 102:35 | Cite as

Tracing the origin of the panda’s thumb

  • Juan AbellaEmail author
  • Alejandro Pérez-Ramos
  • Alberto Valenciano
  • David M. Alba
  • Marcos D. Ercoli
  • Daniel Hontecillas
  • Plinio Montoya
  • Jorge Morales
Original Paper


We investigate the relative development of the carnivoran radial sesamoids to untangle the evolution of this iconic structure. In the pandas (both giant and red), this ‘false thumb’ is known to perform a grasping role during bamboo feeding in both the red and giant pandas. An original locomotor role has been inferred for ailurids, but this remains to be ascertained for ursids. A large sample of radial sesamoids of Indarctos arctoides from the Miocene of Batallones-3 (Spain) indicates that this early ailuropodine bear displayed a relatively hypertrophied radial sesamoid, with a configuration more similar to that of the red panda and other carnivorans than to that of giant pandas. This false thumb is the first evidence of this feature in the Ursidae, which can be linked to a more herbivorous diet. Moreover, in the two extant pandas, the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding, which changes the evolutionary view of this singular structure.


Cerro de los Batallones Late Miocene Radial sesamoid Carnivora Ursidae 



This study was supported by the Spanish Ministerio de Economía y Competitividad (CGL2011-25754, CGL2011-28681 and RYC–2009–04533 to D.M.A.), the Universidad Complutense de Madrid (BSCH-UCM910607) and the Generalitat de Catalunya (2009 SGR 754 GRC and 2014 SGR 416 GRC). J.A. thanks the ‘Proyecto Prometeo’ of the ‘Secretaria de Educación Superior, Ciencia Tecnología e Innovación’, Republic of Ecuador. A.V. is a researcher in formation in the CSIC program JAE-PRE_CP2011 (CSIC program ‘Junta para la ampliación de estudios’), co-funded by the European Social Fund and has received funding from the European Union’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 226506 (SYNTHESYS; SE-TAF-3637), the USC School of Medicine (Columbia, South Carolina, USA) and the AMNH (Collection Study Grant Programme 2014). M.D.E. thanks the MACN for a PhD student grant. We are indebted to S. Roussiakis for photographs of the radial sesamoid of I. punjabiensis from Pikermi; to S. Wallace, M.A. Nieto Cambra, R. Portela Miguez, E. Westwig, D. Lunde, E. López Errasquin, D. Kalthoff, P. Moreno, F. Pastor, D. Flores and S. Lucero and D. Verzi and I. Olivares for the access to comparative material under their care; to M. Bastir (Paleoanthropology Group, MNCN, Spain) for the scans of the radius and ulna of I. arctoides; to Louis de Bonis for his recommendations on the manuscript; to Ó. Sanisidro for Fig. 1; and to the editors and the many reviewers who helped us to improve this manuscript.

Authors’ contribution

J.A., P.M. and J.M. conceived and designed the experiments. J.A., A.P.R. and A.V. performed the experiments. J.A., M.D.E. and A.V. analysed the data. J.A., A.V., A.P.R. and D.H. contributed reagents/materials/analysis tools. J.A., D.M.A. and J.M. wrote the paper.

Supplementary material

114_2015_1286_MOESM1_ESM.docx (154 kb)
Supporting Information Table 1 (SIT 1) List of taxa included in the comparative sample, which includes skeletons of extant and extinct carnivorans, showing sample size (N), species name, housing institution and catalogue number. (DOCX 153 kb)
Supporting information Video 1 (SIV1)

Video showing the grasping action of the right forepaw, based on the fossil remains of Indarctos arctoides from Batallones 3. This video only shows the last phase of the movement, since supination of the forepaw and flexion of carpals and metacarpals occur prior to the digit flexion shown here. (AVI 2443 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Juan Abella
    • 1
    • 2
    Email author
  • Alejandro Pérez-Ramos
    • 3
  • Alberto Valenciano
    • 4
    • 5
  • David M. Alba
    • 2
  • Marcos D. Ercoli
    • 6
  • Daniel Hontecillas
    • 7
  • Plinio Montoya
    • 8
  • Jorge Morales
    • 7
  1. 1.Universidad Estatal Península de Santa Elena, Edificio INCYTLa LibertadEcuador
  2. 2.Institut Català de Paleontologia Miquel CrusafontUniversitat Autònoma de Barcelona, Edifici ICTA-ICPBarcelonaSpain
  3. 3.Departamento de Ecología y Geología, Facultad de CienciasUniversidad de MálagaMálagaSpain
  4. 4.Departamento de Geología Sedimentaria y Cambio MedioambientalInstituto de Geociencias, IGEO (CSIC, UCM)MadridSpain
  5. 5.Departamento de PaleontologíaUniversidad Complutense de MadridMadridSpain
  6. 6.División MastozoologíaMuseo Argentino de Ciencias Naturales “Bernardino Rivadavia”–CONICETBuenos AiresArgentina
  7. 7.Museo Nacional de Ciencias Naturales (MNCN-CSIC)MadridSpain
  8. 8.Departament de Geologia, Àrea de PaleontologiaUniversitat de ValènciaValènciaSpain

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