Sexual dimorphism in histological characteristics and contractility of the iliofibularis muscle in the lizard Sceloporus torquatus |
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Authors: | Erendira Quintana Javier Manjarrez Margarita Martínez‐Gómez Liliana D'Alba Jorge Rodríguez‐Antolín Victor Fajardo |
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Affiliation: | 1. Laboratorio de Conducta Animal, Centro de Investigaciones en Recursos Bióticos‐Facultad de Ciencias, Universidad Autónoma del Estado de México, , Toluca, Estado de México, 50000 México;2. Laboratorio de Biología Evolutiva, Centro de Investigaciones en Recursos Bióticos‐Facultad de Ciencias, Universidad Autónoma del Estado de México, , Toluca, Estado de México, 50000 México;3. Centro Tlaxcala de Biología de la Conducta‐Universidad Autónoma de Tlaxcala, Unidad Periférica del Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, , Tlaxcala, Tlaxcala, 90070 México;4. Department of Biology and Integrated Bioscience Program, University of Akron, , Akron, Ohio, 44325‐3908 USA |
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Abstract: | The iliofibularis is a hindlimb muscle used in lizard locomotion that is composed of at least three types of fibres: fast‐twitch‐glycolytic (FG), fast‐twitch‐oxidative‐glycolytic fibre (FOG) and slow‐twitch‐oxidative (SO). The striated skeletal muscle is a highly plastic tissue undergoing phenotypic change in response to activity. The lizard Sceloporus torquatus has sexual differences associated with microhabitat use, which can be reflected in the physiology and anatomy of the muscle, and thus, in our study, we analysed the morphological and contractile characteristics of the iliofibularis muscle (IF) of S. torquatus males and females. We found a larger prevalence of FOG compared with FG and SO fibres in the muscle of both sexes. We also found that males show larger areas of the three types of fibres, develop greater strength but also faster fatigue than females, suggesting that strength is a key functional feature that enables males to perform faster movements (but for shorter periods), associated with the demands of territoriality. |
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Keywords: | Striated muscle sexual dimorphism histology contractility Sceloporus torquatus lizard |
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