Muscle internal structure revealed by contrast-enhanced μCT and fibre recognition: The hindlimb extensors of an arboreal and a fossorial squirrel

Publication date: November 2019Source: Mammalian Biology, Volume 99Author(s): John A. Nyakatura, Roxane Baumgarten, Daniel Baum, Heiko Stark, Dionisios YoulatosAbstractIn individuals of similar body mass representing closely related species with different lifestyles, muscle architectural properties can be assumed to reflect adaptation to differing, lifestyle-related functional demands. We here employ a fibre recognition algorithm on contrast-enhanced micro-computed tomography (μCT) scans of one specimen each of an arboreal (Sciurus vulgaris) and a fossorial (Spermophilus citellus) sciuromorph rodent. The automated approach accounts for potential heterogeneity of architectural properties within a muscle by analysing all fascicles that compose a muscle. Muscle architectural properties (volume, fascicle length and orientation, and force-generating capacity) were quantified in 14 hindlimb (hip, knee, and ankle) extensor muscles and compared between specimens. We expected the arboreal squirrel to exhibit greater force-generating capacity and a greater capacity for length change allowing more powerful hindlimb extension. Generally and mostly matching our expectations, the S. vulgaris specimen had absolutely and relatively larger extensor muscles than the S. citellus specimen which were thus metabolically more expensive and demonstrate the relatively larger investment into powerful hindlimb extension necessary in the arboreal context. We conclude that detailed quantitative data on ...

Source: Mammalian Biology - November 12, 2019 Category: Biology Source Type: research