The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


When artiodactyls lead anthropologists astray: important considerations, strengths, and limitations of comparing limb bone adaptation between artiodactyls and primates

JOHN G. SKEDROS.

Dept. of Orthopaedics, University of Utah School of Medicine

Friday All day, Plaza Level Add to calendar

Studies of adaptation of artiodactyl (e.g., sheep, deer, gazelles) limb bones are now commonly used as a means for understanding processes/mechanisms of adaptation in appendicular skeletons of primates. Benefits of using artiodactyls include: (1) availability, (2) ease of strain gauge application on some bones, and (3) physiological and anatomical studies that have established them as experimental models for comparisons with humans (e.g. sheep). While benefits of using non-primate experimental/comparative models are clear, there are also important limitations that might not be readily apparent and could confound interpretations. In a recent book chapter (Ch. 7, In Bone Histology: An Anthropological Perspective, 2011; CRC Press), a systematic method is described for identifying manifestations of functional adaptation (primarily in the context of load history) in intra- and inter-specific comparisons of appendicular bones of various species. I will demonstrate how this method helps to identify strengths and limitations when considering data from artiodactyls for understanding adaptation in primate limb bones. Many examples, including important studies in the anthropological literature, will also be presented in this context. Besides obvious issues (e.g., animal size/mass, age, and gender), important considerations include: (1) importance of muscle/tendon/ligament “protection” and load sharing, and why these might evoke seemingly paradoxical modeling/remodeling events, (2) the shift from modeling- to remodeling-based adaptability at skeletal maturity, and (3) how altricial vs. precocial growth can confound interpretations, especially in terms of differences in the growth of bones that become highly osteonal more rapidly vs. those that retain larger percentages of primary histology in the adult.

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