Bilewitch Jaret P, Ekins Merrick, Hooper John, Degnan Sandie M
The University of Queensland, School of Biological Sciences, Brisbane, 4072 QLD, Australia.
Queensland Museum, PO Box 3300, South Brisbane BC, 4101 QLD, Australia.
Mol Phylogenet Evol. 2014 Apr;73:106-18. doi: 10.1016/j.ympev.2014.01.023. Epub 2014 Feb 5.
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.
艾氏珊瑚科的八放珊瑚构成了一个多样且分布广泛的科，根据群体生长形式可细分为不同属。分支模式在几个属中重复出现，同属的珊瑚在给定生长形式下常表现出特定区域的变异。我们利用分子系统发育和祖先形态重建研究了艾氏珊瑚科各属的系统模式以及分支形式多样性的演化。由于生物地理分布与当前分类归属不匹配，所包含的八个属中有六个被发现是多系的，因此有必要创建至少六个新属，并对现有属进行一些重新分类。群体分支形态多样化的系统发育模式在艾氏珊瑚科的两个主要分支中各自呈现出相似的转变顺序，扇形形态被估计为最可能的共同祖先，可能起源于印度 - 太平洋地区。观察到的进化平行性表明，在决定艾氏珊瑚群体形态的遗传因素上存在一种限制。然而，各属之间遗传分化水平与形态多样性之间缺乏对应关系，这表明未来八放珊瑚的研究应聚焦于基因调控变化在分支模式演化中的作用。
