PPG - Zoologia/Departamento de Zoologia - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA.
J Evol Biol. 2021 Feb;34(2):391-402. doi: 10.1111/jeb.13748. Epub 2020 Dec 14.
The mandible of vertebrates serves as insertion area for masticatory muscles that originate on the skull, and its functional properties are subject to selective forces related to trophic ecology. The efficiency of masticatory muscles can be measured as mechanical advantage on the mandible, which, in turn, has the property of correlating with bite force and shape. In the present work, we quantify the mechanical advantage of the mandible of akodontine rodents, which present a diverse radiation of insectivorous specialists, to assess their relationship to the estimated bite force and diet. We also tested the degree of morphofunctional convergence in response to insectivory on the group. We found the mechanical advantages to be convergent on insectivorous species, and associated with the estimated bite force, with higher mechanical advantages in species with a stronger bite and short, robust mandibles and lower mechanical advantages in insectivorous species with weaker bites and more elongated, dorso-ventrally compressed mandibles. Insectivorous species of Akodontini are functional specialists for the consumption of live prey and may exploit the resources that shrews, moles and hedgehogs consume elsewhere.
脊椎动物的下颌骨是咀嚼肌的附着区域，咀嚼肌起源于颅骨，其功能特性受到与营养生态相关的选择压力的影响。咀嚼肌的效率可以用下颌骨的机械优势来衡量，而机械优势反过来又与咬合力和形状有关。在本工作中，我们量化了食虫性专门物种——akodontine 啮齿动物的下颌骨的机械优势，以评估其与估计的咬合力和饮食的关系。我们还测试了该组对食虫性的形态功能趋同程度。我们发现，食虫物种的机械优势是趋同的，并且与估计的咬合力相关，咬合力越强、下颌骨越短越粗壮的物种具有更高的机械优势，而咬合力较弱、下颌骨更长、背腹压缩更严重的食虫物种则具有更低的机械优势。akodontini 科的食虫物种是专门用于捕食活猎物的功能专家，它们可能会利用鼩鼱、鼹鼠和刺猬在其他地方消耗的资源。
