Discovery and phylogenetic analysis of a riverine species flock of African electric fishes (Mormyridae: Teleostei).
Discovery and phylogenetic analysis of a riverine species flock of African electric fishes (Mormyridae: Teleostei).
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非洲电鱼河流物种群的发现和系统发育分析（Mormyridae：Teleostei）。
DOI：
10.1111/j.0014-3820.2002.tb01370.x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Hopkins,CarlD
中科院分区：
文献类型：
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作者：
Sullivan,JohnP;Lavoué,Sébastien;Hopkins,CarlD
物种特异性配偶识别信号的进化在具有有限分布的物种单系群（称为“物种群”）中特别有趣。然而，这些分支中物种形成的爆炸性使得重建它们的系统发育历史变得困难。在这里，我们描述了一个物种群的河流mormyrid鱼从中西部非洲，其中电信号可能在同域物种的生殖隔离中发挥作用。在我们最近的野外采集中，共有来自许多地方的1400多个标本，我们认识到38种形态和电器官放电（EOD）特征不同的形式。在这38个物种中，只有4个明确对应于描述的物种。在这里，我们把这些形式的操作分类单位（OTUs）的系统发育分析的cytochromebsequence数据从86个标本。我们研究了分子数据中对这38个OTU的单系性的支持，每个表型界定的OTU的单系性单独考虑，以及OTU之间的关系与从形态和EOD特征状态的分布推断的那些一致。通过最大简约法和最大似然分析获得的树，植根于外群分类群的序列数据，为这38个OTU相对于其他长颌鱼的单系性提供了证据。许多不同类型之间的小遗传距离表明它们最近的分歧。然而，在许多情况下，细胞色素拓扑结构不能支持单个OTU的单系性以及在形态和EOD特征上相似的OTU之间的密切关系。在其他情况下，来自不同OTU的个体共享相同或几乎相同的单倍型。对这些病例的仔细检查表明，不自然的OTU定义不是这种模式的唯一原因，我们推断线粒体基因树和由不完整的线粒体谱系分选和/或跨形式的基因渗入引起的生物体遗传之间的不一致。这支河流电鱼的明显快速多样化以及与从线粒体数据中恢复有意义的物种水平同源性相关的问题与其他物种群中的发现平行。选择EOD波形作为配偶识别信号可能参与了这些鱼类的辐射。这是第一次描述一个淡水鱼类集群从河流，而不是湖泊，环境。
The evolution of species‐specific mate recognition signals is of particular interest within speciose mono‐phyletic groups with restricted distributions (known as “species flocks”). However, the explosive nature of speciation in these clades makes difficult the reconstruction of their phylogenetic history. Here we describe a species flock of riverine mormyrid fishes from west‐central Africa in which electric signals may play a role in the reproductive isolation of sympatric species. In our recent field collections, totaling more than 1400 specimens from many localities, we recognize 38 forms that are distinct in their morphologies and electric organ discharge (EOD) characteristics. Of these 38, only four clearly correspond to described species. Here we treat these forms as operational taxonomic units (OTUs) in a phylogenetic analysis of cytochromebsequence data from a sample of 86 specimens. We examined support in the molecular data for the monophyly of these 38 OTUs considered together, the monophyly of each phenotypically delimited OTU considered individually, and for relationships among OTUs congruent with those inferred from the distribution of morphological and EOD character states. Trees obtained by both maximum‐parsimony and maximum‐likelihood analyses, rooted with sequence data from outgroup taxa, provide evidence for the monophyly of these 38 OTUs with respect to other mormyrid fishes. The small genetic distances between many distinct forms suggest their recent divergence. However, in many instances the cytochromebtree topology fails to support the monophyly of individual OTUs and close relationships between OTUs that are similar in morphology and EOD characteristics. In other cases, individuals from distinct OTUs share identical or nearly identical haplotypes. Close examination of these cases suggests that unnatural OTU definition is not the sole cause of this pattern, and we infer an incongruence between the mitochondrial gene tree and the organismal phylogeny caused by incomplete mitochondrial lineage sorting and/or introgression across forms. The apparently rapid diversification in this clade of riverine electric fishes and the problems associated with recovering a meaningful species‐level phylogeny from mitochondrial data parallel findings in other species flocks. Selection on EOD waveforms as mate recognition signals may be involved in the radiation of these fishes. This is the first description of a freshwater fish species flock from a riverine, as opposed to a lacustrine, environment.