Musculoskeletal networks reveal topological disparity in mammalian neck evolution

BMC Evolutionary Biology

Research Article

Martin S. Fischer¹  Patrick Arnold²  Borja Esteve-Altava³ 

[1] Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany;Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany;Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Jena, Germany;Structure & Motion Lab, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK;

关键词: Anatomical network analysis;    Network theory;    Forelimb evolution;    Mammalian cervical spine;    Sloths;    Meristic constraints;    Modularity;   

DOI  :  10.1186/s12862-017-1101-1

 received in 2017-05-31, accepted in 2017-11-30,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThe increase in locomotor and metabolic performance during mammalian evolution was accompanied by the limitation of the number of cervical vertebrae to only seven. In turn, nuchal muscles underwent a reorganization while forelimb muscles expanded into the neck region. As variation in the cervical spine is low, the variation in the arrangement of the neck muscles and their attachment sites (i.e., the variability of the neck’s musculoskeletal organization) is thus proposed to be an important source of neck disparity across mammals. Anatomical network analysis provides a novel framework to study the organization of the anatomical arrangement, or connectivity pattern, of the bones and muscles that constitute the mammalian neck in an evolutionary context.ResultsNeck organization in mammals is characterized by a combination of conserved and highly variable network properties. We uncovered a conserved regionalization of the musculoskeletal organization of the neck into upper, mid and lower cervical modules. In contrast, there is a varying degree of complexity or specialization and of the integration of the pectoral elements. The musculoskeletal organization of the monotreme neck is distinctively different from that of therian mammals.ConclusionsOur findings reveal that the limited number of vertebrae in the mammalian neck does not result in a low musculoskeletal disparity when examined in an evolutionary context. However, this disparity evolved late in mammalian history in parallel with the radiation of certain lineages (e.g., cetartiodactyls, xenarthrans). Disparity is further facilitated by the enhanced incorporation of forelimb muscles into the neck and their variability in attachment sites.

【 授权许可】

CC BY   
© The Author(s). 2017

【 图 表 】

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Fig. 7