Skip to main content Accessibility help

The effects of skeletal asymmetry on interpreting biologic variation and taphonomy in the fossil record

  • Brandon P. Hedrick (a1), Emma R. Schachner (a2), Gabriel Rivera (a3), Peter Dodson (a4) and Stephanie E. Pierce (a1)...


Biologic asymmetry is present in all bilaterally symmetric organisms as a result of normal developmental instability. However, fossilized organisms, which have undergone distortion due to burial, may have additional asymmetry as a result of taphonomic processes. To investigate this issue, we evaluated the magnitude of shape variation resulting from taphonomy on vertebrate bone using a novel application of fluctuating asymmetry. We quantified the amount of total variance attributed to asymmetry in a taphonomically distorted fossil taxon and compared it with that of three extant taxa. The fossil taxon had an average of 27% higher asymmetry than the extant taxa. In spite of the high amount of taphonomic input, the major axes of shape variation were not greatly altered by removal of the asymmetric component of shape variation. This presents the possibility that either underlying biologic trends drive the principal directions of shape change irrespective of asymmetric taphonomic distortion or that the symmetric taphonomic component is large enough that removing only the asymmetric component is inadequate to restore fossil shape. Our study is the first to present quantitative data on the relative magnitude of taphonomic shape change and presents a new method to further explore how taphonomic processes impact our interpretation of the fossil record.



Hide All

Present address: Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, U.K.

Data available from the Dryad Digital Repository:



Hide All
Adams, D. C., and Otárola-Castillo, E.. 2013. geomorph: an R package for the collection and analysis of geometric morphometric shape data. Methods in Ecology and Evolution 4:393399.
Angielczyk, K. D., and Sheets, H. D.. 2007. Investigation of simulated tectonic deformation in fossils using geometric morphometrics. Paleobiology 33:125148.
Arbour, V. M., and Currie, P. J.. 2012. Analyzing taphonomic deformation of ankylosaur skulls using retrodeformation and finite element analysis. PLoS ONE 7:e39323.
Baert, M., Burns, M. E., and Currie, P. J.. 2014. Quantitative diagenetic analyses of Edmontosaurus regalis (Dinosauria: Hadrosauridae) postcranial elements from the Danek Bonebed, Upper Cretaceous Horseshoe Canyon Formation, Edmonton, Alberta, Canada: implications for allometric studies of fossil organisms. Canada Journal of Earth Science 51:10071016.
Balmford, A., Jones, I. L., and Thomas, A. L. R.. 1993. On avian asymmetry: evidence of natural selection for symmetrical tails and wings in birds. Proceedings of the Royal Society of London B 252:245251.
Bongard, J. C., and Paul, C.. 2000. Investigating morphological symmetry and locomotive efficiency using virtual embodied evolution. In Proceedings of the Sixth Internation Conference on Simulation of Adaptive Behavior, 420–429. MIT Press.
Boyd, A. A., and Motani, R.. 2008. Three-dimensional re-evaluation of the deformation removal technique based on “jigsaw puzzling.” Palaeontologia Electronica 11(2):7A.
Brusatte, S. L., Sakamoto, M., Montanari, S., and Harcourt Smith, W. E. H.. 2012. The evolution of cranial form and function in theropod dinosaurs: insights from geometric morphometrics. Journal of Evolutionary Biology 25:365377.
Cooper, R. A. 1990. Interpretation of tectonically deformed fossils. New Zealand Journal of Geology and Geophysics 33:321332.
Davis, G. H., and Reynolds, S. J.. 1996. Structural geology of rocks and regions, 2nd ed. Wiley, New York.
Dongen, S. V. 2006. Fluctuating asymmetry and developmental instability in evolutionary biology: past, present, and future. European Society for Evolutionary Biology 19:17271743.
Fank, A. 1929. Die bruchlose Deformation von Fossilien durch tektonischen Druckundihr Einflussaufdie Bestimmungder Arten. Unpublished dissertation, University of Zurich, Switzerland. 59 p., 16 tables.
Foth, C., Hedrick, B. P., and Ezcurra, M. D.. 2016. Cranial ontogenetic variation in early saurischians and the role of heterochrony in the diversification of predatory dinosaurs. PeerJ 4:e1589.
Galeotti, P., Sacchi, R., and Vicario, V.. 2005. Fluctuating asymmetry in body traits increases predation risks: tawny owl selection against asymmetric woodmice. Evolutionary Ecology 19:405418.
Gunz, P., Mitteroecker, P., Neubauer, S., Weber, G. W., and Bookstein, F. L.. 2009. Principles for the virtual reconstruction of hominin crania. Journal of Human Evolution 47:4862.
Hambly, C., Harper, E. J., and Speakman, J. R.. 2004. The energetic cost of variations in wing span and wing asymmetry in the zebra finch Taeniopygia guttata. Journal of Experimental Biology 207:39773984.
Hedrick, B. P., and Dodson, P.. 2013. Lujiatun psittacosaurids: understanding individual and taphonomic variation using 3D geometric morphometrics. PLoS ONE 8:e69265.
Hughes, N. C., and Jell, P. A.. 1992. A statistical/computer-graphic technique for assessing variation in tectonically deformed fossils and its application to Cambrian trilobites from Kashmir. Lethaia 25:317330.
Klingenberg, C. P., and McIntyre, G. S.. 1998. Geometric morphometrics of developmental instability: analyzing patterns of fluctuating asymmetry with Procrustes methods. Evolution 52:13631375.
Klingenberg, C. P., Barluenga, M., and Meyer, A.. 2002. Shape analysis of symmetric structures: quantifying variation among individuals and asymmetry. Evolution 56:19091920.
Leamy, L. J., and Klingenberg, C. P.. 2005. The genetics and evolution of fluctuating asymmetry. Annual Review of Ecology, Evolution, and Systematics 36:121.
Maidment, S. C. R., and Barrett, P. M.. 2012. Osteological correlates for quadrupedality in ornithischian dinosaurs. Acta Palaeontologica Polonica 59:5370.
Maiorino, L., Farke, A. A., Kotsakis, T., and Piras, P.. 2013. Is Torosaurus Triceratops? Geometric morphometrics evidence of Late Maastrichtian ceratopsid dinosaurs. PLoS ONE 8:e81608.
Mardia, K. V., Bookstein, F. L., and Moreton, I. J.. 2000. Statistical assessment of bilateral symmetry of shapes. Biometrika 87:285300.
Møller, A. P., and Thornhill, R.. 1998. Bilateral symmetry and sexual selection: a meta-analysis. American Naturalist 151:174192.
Motani, R. 1997. New technique for retrodeforming tectonically deformed fossils, with an example for ichthyosaurian specimens. Lethaia 30:221228.
Ogihara, N., Nakatsukasa, M., Nakano, Y., and Ishida, H.. 2006. Computerized restoration of nonhomogenous deformation of a fossil cranium based on bilateral symmetry. American Journal of Physical Anthropology 130:19.
Olejnik, S., and Algina, J.. 2003. Generalized eta and omega squared statistics: measures of effect size for some common research designs. Psychological Methods 8:434447.
Perez, S. I., Bernal, V., and Gonzalez, P. N.. 2006. Differences between sliding semi-landmark methods in geometric morphometrics, with an application to human craniofacial and dental variation. Journal of Anatomy 208:769784.
Pierce, S. E., Angielczyk, K. D., and Rayfield, E. J.. 2009. Shape and mechanics in thalattosuchian (Crocodylomorpha) skulls: implications for feeding behaviour and niche partitioning. Journal of Anatomy 215:555576.
Preston, C. R. 2000. Red-tailed hawk. Stackpole Books, Mechanicsburg, Penn. 103 pp.
Ramsay, J. G., and Huber, M. I.. 1983. The techniques of modern structural geology, Vol. 1. Strain analysis. Academic, London.
R Core Team. 2017. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Accessed 15 February 2018.
Rivera, G., and Claude, J.. 2008. Environmental media and shape asymmetry: a case study on turtle shells. Biological Journal of the Linnean Society 94:483489.
Rivera, G., and Stayton, C. T.. 2013. Effects of asymmetry on the strength of the chelonian shell: a comparison of three species. Journal of Morphology 274:901908.
Rohlf, F. J. 2006. tpsDig, digitize landmarks and outlines, Version 2.05. Department of Ecology and Evolution, State University of New York, Stony Brook, N.Y.
Schmieder, D. A., Benítez, H. A., Borissov, I. M., and Fruciano, C.. 2015. Bat species comparisons based on external morphology: a test of traditional versus geometric morphometric approaches. PLoS ONE 10:e0127043.
Sereno, P. C. 2010. Taxonomy, cranial morphology, and relationships of parrot-beaked dinosaurs (Ceratopsia: Psittacosaurus). Pp. 2158 in Ryan, M. J., Chinnery-Allgeier, B. J., and Eberth, D. A., eds. New perspectives on horned dinosaurs. Indiana University Press, Bloomington.
Swaddle, J. P. 2003. Fluctuating asymmetry, animal behavior, and evolution. Advances in the Study of Behavior 32:169206.
Swaddle, J. P., and Johnson, C. W.. 2007. European starlings are capable of discriminating subtle size asymmetries in paired stimuli. Journal of the Experimental Analysis of Behavior 87:3949.
Tschopp, E., Russo, J., and Dzemski, G.. 2013. Retrodeformation as a test for the validity of phylogenetic characters: an example from diplodocid sauropod vertebrae. Palaeontologia Electronica 16:123.
White, T. 2003. Early hominids—diversity or distortion? Science 299:19941997.
Willmore, K. E., Klingenberg, C. P., and Hallgrímsson, B.. 2005. The relationship between fluctuating asymmetry and environmental variance in rhesus macaque skulls. Evolution 59:898909.
Witmer, L. M. 1995. The extant phylogenetic bracket and the importance of reconstructing soft tissues in fossils. Pp. 1933 in Thomason, J., ed. Functional morphology in vertebrate paleontology. Cambridge University Press, New York.
Zelditch, M. L., Wood, A. R., Bonett, R. M., and Swiderski, D. L.. 2008. Modularity of the rodent mandible: integrating bones, muscles, and teeth. Evolution and Development 10:756768.
Zelditch, M. L., Swiderski, D. L., Sheets, H. D., and Fink, W. L.. 2012. Geometric Morphometrics for Biologists: A Primer, 2nd ed. Elsevier Academic, London.
Zhao, Q., Benton, M. J., Sullivan, C., Sander, P. M., and Xing, X.. 2013. Histology and postural change during the growth of the ceratopsian dinosaur Psittacosaurus lujiatunesis. Nature Communications 4(2079):18.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

  • ISSN: 0094-8373
  • EISSN: 1938-5331
  • URL: /core/journals/paleobiology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed