Evolution of bone compactness in extant and extinct moles Talpidae: exploring humeral microstructure in small fossorial mammalsReport as inadecuate




Evolution of bone compactness in extant and extinct moles Talpidae: exploring humeral microstructure in small fossorial mammals - Download this document for free, or read online. Document in PDF available to download.

BMC Evolutionary Biology

, 13:55

Evolutionary developmental biology and morphology

Abstract

BackgroundTalpids include forms with different degree of fossoriality, with major specializations in the humerus in the case of the fully fossorial moles. We studied the humeral microanatomy of eleven extant and eight extinct talpid taxa of different lifestyles and of two non-fossorial outgroups and examined the effects of size and phylogeny. We tested the hypothesis that bone microanatomy is different in highly derived humeri of fossorial taxa than in terrestrial and semi-aquatic ones, likely due to special mechanical strains to which they are exposed to during digging. This study is the first comprehensive examination of histological parameters in an ecologically diverse and small-sized mammalian clade.

ResultsNo pattern of global bone compactness was found in the humeri of talpids that could be related to biomechanical specialization, phylogeny or size. The transition zone from the medullary cavity to the cortical compacta was larger and the ellipse ratio smaller in fossorial talpids than in non-fossorial talpids. No differences were detected between the two distantly related fossorial clades, Talpini and Scalopini.

ConclusionsAt this small size, the overall morphology of the humerus plays a predominant role in absorbing the load, and microanatomical features such as an increase in bone compactness are less important, perhaps due to insufficient gravitational effects. The ellipse ratio of bone compactness shows relatively high intraspecific variation, and therefore predictions from this ratio based on single specimens are invalid.

KeywordsWolff’s law Paleohistology Size Phylogeny Placentalia Electronic supplementary materialThe online version of this article doi:10.1186-1471-2148-13-55 contains supplementary material, which is available to authorized users.

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Author: Patricia S Meier - Constanze Bickelmann - Torsten M Scheyer - Daisuke Koyabu - Marcelo R Sánchez-Villagra

Source: https://link.springer.com/







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