Molecular and morphological systematics of the Ellisellidae (Coelenterata: Octocorallia): Parallel evolution in a globally distributed family of octocorals

Bilewitch, Jaret P.; Ekins, Merrick; Hooper, John; Degnan, Sandie M.

Type

Article

Authors

Bilewitch, Jaret P.
Ekins, Merrick
Hooper, John
Degnan, Sandie M.

Date

2014-04

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http://hdl.handle.net/10754/598870

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Abstract

The octocorals of the Ellisellidae constitute a diverse and widely distributed family with subdivisions into genera based on colonial growth forms. Branching patterns are repeated in several genera and congeners often display region-specific variations in a given growth form. We examined the systematic patterns of ellisellid genera and the evolution of branching form diversity using molecular phylogenetic and ancestral morphological reconstructions. Six of eight included genera were found to be polyphyletic due to biogeographical incompatibility with current taxonomic assignments and the creation of at least six new genera plus several reassignments among existing genera is necessary. Phylogenetic patterns of diversification of colony branching morphology displayed a similar transformation order in each of the two primary ellisellid clades, with a sea fan form estimated as the most-probable common ancestor with likely origins in the Indo-Pacific region. The observed parallelism in evolution indicates the existence of a constraint on the genetic elements determining ellisellid colonial morphology. However, the lack of correspondence between levels of genetic divergence and morphological diversity among genera suggests that future octocoral studies should focus on the role of changes in gene regulation in the evolution of branching patterns. © 2014 Elsevier Inc.

Citation

Bilewitch JP, Ekins M, Hooper J, Degnan SM (2014) Molecular and morphological systematics of the Ellisellidae (Coelenterata: Octocorallia): Parallel evolution in a globally distributed family of octocorals. Molecular Phylogenetics and Evolution 73: 106–118. Available: http://dx.doi.org/10.1016/j.ympev.2014.01.023.

Sponsors

This research was supported by funding from the Australian Research Council to SMD and a Society for Systematic Biology Graduate Student Award to JPB. We acknowledge the support of ABRS Grant Number 209-05, “Taxonomy of tropical Australian Octocorallia (Anthozoa: Coelenterata) primarily from the Census of Marine Life ‘CReefs’ expeditions”, investigators J.N.A. Hooper and P.N. Alderslade, for sharing collections of octocorals from the east and west coast of Australia for present analyses.We gratefully acknowledge the generous donation of samples from the following individuals and institutions: Sue Horner, Museum and Art Galleries of the Northern Territory; Steve Cairns, Smithsonian National Museum of Natural History; Andrew Cabrinovic, Natural History Museum; Gary Williams, Christina Piotrowski and Kelly Markello, California Academy of Science; Pedro Ribeiro and Ana Raposo, University of the Azores; Chris Voolstra, King Abdullah University of Science and Technology; Kareen Schnabel and Sadie Mills, National Institute of Water and Atmospheric Research; Scott France and Esprit Heestand Saucier, University of Louisiana at Lafayette.This work benefitted from discussion and support provided by members of the Degnan Labs (University of Queensland), Phil Alderslade (CSIRO) and Monika Bryce (Western Australian Museum). We also thank two anonymous reviewers for their constructive comments and improvement of the manuscript.