Evolution of anthozoan polyp retraction mechanisms: convergent functional morphology and evolutionary allometry of the marginal musculature in order Zoanthidea (Cnidaria: Anthozoa: Hexacorallia)

BMC Evolutionary Biology

Research Article

Jennifer L. Schellinger¹  Anna M. Strimaitis¹  Kim E. Reuter²  Timothy D. Swain³ 

[1] Department of Biological Science, Florida State University, 32306-4295, Tallahassee, FL, USA;Department of Biology, Temple University, 19122, Philadelphia, PA, USA;Department of Civil and Environmental Engineering, Northwestern University, 60208, Evanston, IL, USA;Department of Zoology, Field Museum of Natural History, 60605, Chicago, IL, USA;

关键词: Phylogenetic comparative methods;    Functional morphology;    Convergent evolution;    Evolutionary allometry;    Coelenterata;    Hexacorallia;    Symbiosis;   

DOI  :  10.1186/s12862-015-0406-1

 received in 2015-04-08, accepted in 2015-06-02,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundRetraction is among the most important basic behaviors of anthozoan Cnidaria polyps and is achieved through the coordinated contraction of at least six different muscle groups. Across the Anthozoa, these muscles range from unrecognizable atrophies to massive hypertrophies, producing a wide diversity of retraction abilities and functional morphologies. The marginal musculature is often the single largest component of the retraction mechanism and is composed of a diversity of muscular, attachment, and structural features. Although the arrangements of these features have defined the higher taxonomy of Zoanthidea for more than 100 years, a decade of inferring phylogenies from nucleotide sequences has demonstrated fundamental misconceptions of their evolution.ResultsHere we expand the diversity of known marginal muscle forms from two to at least ten basic states and reconstruct the evolution of its functional morphology across the most comprehensive molecular phylogeny available. We demonstrate that the evolution of these forms follows a series of transitions that are much more complex than previously hypothesized and converge on similar forms multiple times. Evolution of the marginal musculature and its attachment and support structures are partially scaled according to variation in polyp and muscle size, but also vary through evolutionary allometry.ConclusionsAlthough the retraction mechanisms are diverse and their evolutionary histories complex, their morphologies are largely reflective of the evolutionary relationships among Zoanthidea higher taxa and may offer a key feature for integrative systematics. The convergence on similar forms across multiple linages of Zoanthidea mirrors the evolution of the marginal musculature in another anthozoan order (Actiniaria). The marginal musculature varies through evolutionary allometry of functional morphologies in response to requirements for additional force and resistance, and the specific ecological and symbiotic functions of individual taxa.

【 授权许可】

CC BY   
© Swain et al. 2015

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