Comparative lever analysis and ontogenetic scaling in esocid fishes: Functional demands and constraints in feeding biomechanics

2016 ◽  
Vol 277 (11) ◽  
pp. 1447-1458 ◽  
Author(s):  
Courtney L. Goulet ◽  
Harrison J. Smith ◽  
Takashi Maie
Keyword(s):  
2018 ◽  
Vol 27 (2) ◽  
pp. 199-209 ◽  
Author(s):  
D. Rex Mitchell ◽  
Emma Sherratt ◽  
Gabriele Sansalone ◽  
Justin A. Ledogar ◽  
Richard J. Flavel ◽  
...  

2009 ◽  
Vol 106 (7) ◽  
pp. 2124-2129 ◽  
Author(s):  
D. S. Strait ◽  
G. W. Weber ◽  
S. Neubauer ◽  
J. Chalk ◽  
B. G. Richmond ◽  
...  

2014 ◽  
Vol 298 (1) ◽  
pp. 145-167 ◽  
Author(s):  
Amanda L. Smith ◽  
Stefano Benazzi ◽  
Justin A. Ledogar ◽  
Kelli Tamvada ◽  
Leslie C. Pryor Smith ◽  
...  

Scholarpedia ◽  
2007 ◽  
Vol 2 (9) ◽  
pp. 4165 ◽  
Author(s):  
Hillel Chiel
Keyword(s):  

2017 ◽  
Author(s):  
Dan Puljan ◽  
Curt Anderson

It is well documented that coordination of feeding behavior in anuran amphibians requires precise coordination of the jaw levators and depressors with the timing of the protraction of the tongue. (for review, see Nishikawa, 2000). However, the neuronal mechanism initiating and synchronizing this coordination is not well understood. In addition to the intermandibularis muscle and tongue musculature in the lower jaw, there is a small, transverse muscle at the tip of the jaw, the m. submentalis. Previous anatomical work has demonstrated the presence of muscle spindles in the submentalis, leading to the hypothesis that the activation of this muscle may provide proprioceptive information to aid in coordinating the feeding biomechanics in Rhinella marina. Here, we demonstrate that the submentalis likely acts as a ‘trigger’ to initiate the hypoglossal nerve to activate the tongue, and without feedback information from the muscle spindles of the submentalis, tongue protraction is compromised.


2016 ◽  
Author(s):  
Justin A. Ledogar ◽  
Paul C. Dechow ◽  
Qian Wang ◽  
Poorva H Gharpure ◽  
Adam D. Gordon ◽  
...  

The evolution of the modern human (Homo sapiens) cranium is characterized by a reduction in the size of the feeding system, including reductions in the size of the facial skeleton, postcanine teeth, and the muscles involved in biting and chewing. The conventional view hypothesizes that gracilization of the human feeding system is related to a shift toward eating foods that were less mechanically challenging to consume and/or foods that were processed using tools before being ingested. This hypothesis predicts that human feeding systems should not be well-configured to produce forceful bites and that the cranium should be structurally weak. An alternate hypothesis states that the modern human face is adapted to generate and withstand high biting forces. We used finite element analysis (FEA) to test two opposing mechanical hypotheses: that compared to our closest living relative, chimpanzees (Pan troglodytes), the modern human craniofacial skeleton is 1) less well configured, or 2) better configured to generate and withstand high magnitude bite forces. We considered intraspecific variation in our examination of human feeding biomechanics by examining a sample of geographically diverse crania that differed notably in shape. We found that our biomechanical models of human crania had broadly similar mechanical behavior despite their shape variation and were, on average, less structurally stiff than the crania of chimpanzees during unilateral biting when loaded with physiologically-scaled muscle loads. Our results also show that modern humans are efficient producers of bite force, consistent with previous analyses. However, highly tensile reaction forces were generated at the working (biting) side jaw joint during unilateral molar bites in which the chewing muscles were recruited with bilateral symmetry. In life, such a configuration would have increased the risk of joint dislocation and constrained the maximum recruitment levels of the masticatory muscles on the balancing (non-biting) side of the head. Our results do not necessarily conflict with the hypothesis that anterior tooth (incisors, canines, premolars) biting could have been selectively important in humans, although the reduced size of the premolars in humans has been shown to increase the risk of tooth crown fracture. We interpret our results to suggest that human craniofacial evolution was probably not driven by selection for high magnitude unilateral biting, and that increased masticatory muscle efficiency in humans is likely to be a secondary byproduct of selection for some function unrelated to forceful biting behaviors. These results are consistent with the hypothesis that a shift to softer foods and/or the innovation of pre-oral food processing techniques relaxed selective pressures maintaining craniofacial features favoring forceful biting and chewing behaviors, leading to the characteristically small and gracile faces of modern humans.


2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Amanda L Smith ◽  
Stefano Benazzi ◽  
Justin A Ledogar ◽  
Leslie Smith ◽  
Gerhard W Weber ◽  
...  

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