Published: 29 May 2015 | Last Updated: 29 May 2015 13:41:17

The RVC's Structure and Motion Lab has received the Journal of Anatomy's Runner Up Best Paper Prize 2014 for the following paper:

Comparative architectural properties of limb muscles in Crocodylidae and Alligatoridae and their relevance to divergent use of asymmetrical gaits in extant Crocodylia
V. Allen, J. Molnar, W. Parker, A. Pollard, G. Nolan and J.R. Hutchinson Journal of Anatomy, Volume 225, Issue 6, December 2014, pp569–582

The article reports on Crocodiles and their kin (Crocodylidae) who use asymmetrical (bounding and galloping) gaits when moving rapidly, whereas alligators and their kin do not, despite being morphologically and ecologically similar. To investigate a possible anatomical basis for this apparent major difference in locomotor capabilities, the researchers measured relative masses and internal architecture (fascicle lengths and physiological cross-sectional areas) of muscles of the pectoral and pelvic limbs of 40 individuals from six representative species of Crocodylidae and Alligatoridae. They found that, relative to body mass, Crocodylidae have significantly longer muscle fascicles (increased working range), particularly in the pectoral limb, and generally smaller muscle physiological cross-sectional areas (decreased force-exerting capability) than Alligatoridae. They therefore hypothesise that the ability of some crocodylians to use asymmetrical gaits may be limited more by the ability to make large, rapid limb motions (especially in the pectoral limb) than the ability to exert large limb forces. Furthermore, analysis of scaling patterns in muscle properties shows that limb anatomy in the two clades becomes more divergent during ontogeny. Limb muscle masses, fascicle lengths and physiological cross-sectional areas scale with significantly larger coefficients in Crocodylidae than Alligatoridae. This combination of factors suggests that inter-clade disparity in maximal limb power is highest in adult animals. Therefore, despite their apparent morphological similarities, both mean values and scaling patterns suggest that considerable diversity exists in the locomotor apparatus of extant Crocodylia.

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