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

• DOI: 10.1186/s12862-015-0406-1
• Publication Date: 2015-06-29T11:17:57Z
• Authors: Timothy D. Swain; Jennifer L. Schel...; Anna M. Strimaitis; Kim E. Reuter
• Keywords: Allometry; Anthozoa; Convergent evolution

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