, Volume 129, Issue 3, pp 185–194 | Cite as

How long is a piece of Strix? Methods in measuring and measuring the measurers

  • Paolo ViscardiEmail author
  • Manabu Sakamoto
  • Julia D. Sigwart
Original Paper


An experiment to quantify intra- and interobserver error in anatomical measurements found that interobserver measurements can vary by over 14% of mean specimen length; disparity in measurement increases logarithmically with the number of contributors; instructions did not reduce variation or measurement disparity; scale of the specimen influenced the precision of measurement (relative error increasing with specimen size); different methods of taking a measurement yielded different results, although they did not differ in terms of precision, and topographical complexity of the elements being considered may potentially influence error (error increasing with complexity). These results highlight concerns about introduction of noise and potential bias that should be taken into account when compiling composite datasets and meta-analyses.


Measurement Methods Composite data Morphometrics Error Meta-analysis Anatomy Observer error 



We gratefully acknowledge the unidentified reviewer whose comments have substantially improved the structure and content of this paper. We especially thank Dr. Gareth Dyke and the others involved in the conference organisation of the 56th Symposium of Vertebrate Palaeontology and Comparative Anatomy (Dublin, 2008) for facilitating the experiment. We are grateful to all of the SVPCA attendees for constructive discussion and the 51 individual delegates who contributed their measurements. Additional thanks goes to Beulah Garner for her comments on this manuscript.


  1. Adams DC, Rohlf FJ, Slice DE (2004) Geometric morphometrics: ten years of progress following the ‘revolution’. Ital J Zool 71:5–16CrossRefGoogle Scholar
  2. Ashton KG, Tracy MC, de Queiroz A (2000) Is Bergmann’s rule valid for mammals? Am Nat 156(4):390–415CrossRefGoogle Scholar
  3. Bailey SE, Pilbrow VC, Wood BA (2004) Interobserver error involved in independent attempts to measure cusp base areas of Pan M1s. J Anat 205:323–331CrossRefPubMedGoogle Scholar
  4. Bochenski ZM (2008) Identification of skeletal remains of closely related species: the pitfalls and solutions. J Archeol Sci 35:1247–1250CrossRefGoogle Scholar
  5. Bochenski ZM, Tomek T (1995) How many comparative skeletons do we need to identify a bird bone? Courier Forschunginstitut Senckrnberg 181:357–361Google Scholar
  6. Chen P-J, Dong Z-M, Zhen S-N (1998) An exceptionally well-preserved theropod dinosaur from the Yixian Formation of China. Nat 391:147–152CrossRefGoogle Scholar
  7. Christiansen P, Adolfssen JS (2005) Bite force canine strength and skull allometry in carnivores (Mammalia Carnivora). J Zool Lon 266:133–151CrossRefGoogle Scholar
  8. Clegg SM, Owens IPF (2002) The ‘island rule’ in birds: medium body size and its ecological explanation. P Roy Soc Lond B Bio 269(1498):1359–1365CrossRefGoogle Scholar
  9. Conover WJ, Johnson ME, Johnson MM (1981) A comparative study of tests for homogeneity of variances, with applications to the outer continental shelf bidding data. Technometrics 23(4):351–361CrossRefGoogle Scholar
  10. Constantinescu GM (2002) Clinical anatomy for small animal practitioners. Iowa State Press, Blackwell Publishing Company, IowaGoogle Scholar
  11. Creighton GK (1980) Static allometry of mammalian teeth and the correlation of tooth size and body size in contemporary mammals. J Zoo 191:435–443CrossRefGoogle Scholar
  12. Currie PJ, Zhao X-J (1993) A new carnosaur (Dinosauria Theropoda) from the Jurassic of Xinjiang People’s Republic of China. Can J Earth Sci 30(10):2037–2081Google Scholar
  13. Delany MJ, Healy MJR (1965) Variation in the white-toothed shrews (Crocidura spp) in the British Isles. Proc Roy Soc Lond B Bio 164(994):63–74CrossRefGoogle Scholar
  14. Dryden IL, Mardia KV (1998) Statistical analysis of shape. Wiley, LondonGoogle Scholar
  15. Erickson GM, Lappin AK, Vliet KA (2003) The ontogeny of bite-force performance in American alligator (Alligator mississippiensis). J Zool 260:317–327CrossRefGoogle Scholar
  16. Farlow JO, Hurlburt GR, Elsey RM, Britton ARC, Langston W (2005) Femoral dimensions and body size of Alligator mississippiensis: estimating the size of extinct mesoeucrocodylians. J Vertebr Paleontol 25(2):354–369CrossRefGoogle Scholar
  17. Fligner MA, Killeen TJ (1976) Distribution-free two-sample tests for scale. J Am Stat Assoc 71(353):210–213CrossRefGoogle Scholar
  18. Freeman S, Jackson WM (1990) Univariate metrics are not adequate to measure avian body size. Auk 107(1):69–74Google Scholar
  19. Hammer Ø, Harper DAT, Ryan PD (2001) PAST: paleontological statistics software package for education and data analysis. Palaeontol Electron 4(1):9. http://palaeo-electronicaorg/2001_1/past/issue1_01htm. Accessed 6 Mar 2009
  20. Herrel A, de Grauw E, Lemos-Espinal JA (2001) Head shape and bite performance in xenosaurid lizards. J Exp Zool 290:101–107CrossRefPubMedGoogle Scholar
  21. Holtz T (1994) The arctometatarsalian pes, an unusual structure of the metatarsus of Cretaceous Theropoda (Dinosauria: Saurischia). J Vertebr Paleontol 14(4):480–519Google Scholar
  22. Kieser JA, Groeneveld HT (1987) Static intraspecific allometry of jaws and teeth in Cercopithecus aethiops. J Zool 212:499–510CrossRefGoogle Scholar
  23. Laurin M (2004) The evolution of body size, Cope’s rule and the origin of Amniotes. Syst Biol 53(4):594–622CrossRefPubMedGoogle Scholar
  24. Lee S, Mill PJ (2004) Cranial variation in British mustelids. J Morphol 260(1):57–64CrossRefPubMedGoogle Scholar
  25. Lynch JM, Whelan R, Il Fituri AI, Hayden TJ (1997) Craniometric variation in the Eurasian badger. J Zool 242:31–44CrossRefGoogle Scholar
  26. Marcus LF, Hingst-Zaher E, Zaher H (2000) Application of landmark morphometrics to skulls representing the orders of living mammals. Hystrix 11(1):27–47Google Scholar
  27. Melisch R, Reitshel M (1996) The Eurasian otter Lutra lutra in Afghanistan. Bonn Zool Beitr 46:367–375Google Scholar
  28. Meyers JJ, Herrel A, Birch J (2002) Scaling of morphology bite force and feeding kinematics in an iguanian and scleroglossan lizard. In: Aerts P, D’Aout K, Herrel A, Van Damme R (eds) Topics in functional ecological vertebrate morphology. Shaker Publishing, Maastricht, pp 47–62Google Scholar
  29. Nudds RL, Dyke GJ, Rayner JMV (2004) Forelimb proportions and the evolutionary radiation of Neornithes. Proc Roy Soc Lond B Bio 271(5):S324–S327CrossRefGoogle Scholar
  30. Pierce SE, Angielczyk KD, Rayfield EJ (2008) Patterns of morphospace occupation and mechanical performance in extant crocodilian skulls: a combined geometric morphometric and finite element modeling approach. J Morphol 269(7):840–864CrossRefPubMedGoogle Scholar
  31. Rohlf FR (1990) Morphometrics. Annu Rev Ecol Syst 21:299–316CrossRefGoogle Scholar
  32. Schnell GD, Worthen GL, Douglas ME (1985) Morphometric assessment of sexual dimorphism in skeletal elements of California gulls. Condor 87(4):484–493CrossRefGoogle Scholar
  33. Sues HD (1977) The skull of Velociraptor mongoliensis a small Cretaceous theropod dinosaur from Mongolia. Paläontol Z 51:173–184Google Scholar
  34. Thomason JJ (1991) Cranial strength in relation to estimated biting forces in some mammals. Can J Zool 69:2326–2333CrossRefGoogle Scholar
  35. Tiwari M, Bjorndal KA (2000) Variation in morphology and reproduction in loggerheads, Caretta caretta, nesting in the United States, Brazil, and Greece. Herpetologica 56(3):343–356Google Scholar
  36. Turner AH, Pol D, Clarke JA, Erickson GM, Norell MA (2007) A basal dromaeosaurid and size evolution preceding avian flight. Science 317:1378–1381CrossRefPubMedGoogle Scholar
  37. Van Valkenburgh B (1990) Skeletal and dental predictors of body mass in carnivores. In: Damuth J, MacFadden BJ (eds) Body size in mammalian paleobiology. Cambridge University Press, Cambridge, pp 181–205Google Scholar
  38. Van Valkenburgh B, Sacco T (2002) Sexual dimorphism, social behaviour, and intrasexual competition in large Pleistocene carnivorans. J Vertebr Paleontol 22(1):164–169CrossRefGoogle Scholar
  39. Wiig Ø (1985) Multivariate variation in feral American mink (Mustela vison) from Southern Norway. J Zool 206(3):441–452Google Scholar
  40. Wiig Ø (1986) Sexual dimorphism in the skull of minks Mustela vison badgers Meles meles and otters Lutra lutra. Zool J Linn Soc 87(2):163–179CrossRefGoogle Scholar
  41. Wroe S, McHenry C, Thomason J (2005) Bite club: comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa. Proc Roy Soc Lond B Bio 272:619–625CrossRefGoogle Scholar
  42. Yates AM (2007) Anchisaurus polyzelus (Hitchcock): the smallest known sauropod dinosaur and the evolution of gigantism among sauropodomorph dinosaurs. Postilla 230:1–57Google Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Paolo Viscardi
    • 1
    Email author
  • Manabu Sakamoto
    • 2
  • Julia D. Sigwart
    • 3
  1. 1.Horniman Museum and GardensForest HillUK
  2. 2.Department of Earth SciencesUniversity of BristolBristolUK
  3. 3.School of Biological SciencesQueen’s University BelfastNorthern IrelandUK

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