Echelle Anthony A, Lang Nicholas J, Borden W Calvin, Schwemm Michael R, Hoagstrom Christopher W, Eisenhour David J, Mayden Richard L, Bussche Ronald A van den
Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma, 74078 USA..
Zootaxa. 2018 Jan 25;4375(4):537-554. doi: 10.11646/zootaxa.4375.4.4.
The North American fish genus Macrhybopsis (Teleostei: Cyprinidae) as presently conceived comprises 12 species and occurs in much of interior eastern North America. Variation in the mitochondrial ND2 gene and the nuclear S7 intron 1 reveal conflicting gene-tree relationships for deeper nodes, which are assumed to represent past introgression and heterospecific mitochondrial fixation. The results support monophyly for the wide-ranging M. aestivalis complex with successive sister relationships to M. gelida, M. meeki, and M. storeriana. The current species-level taxonomy of Macrhybopsis is generally supported. Species status is supported for the morphologically distinct M. australis and M. tetranema, both of which are genetically introgressed by M. hyostoma. The results agree with previous suggestions that the wide-ranging M. hyostoma harbors cryptic species. Similar crypticity is indicated for the poorly sampled M. storeriana; a sample from the Pearl River shows 8% ND2 divergence from two Mississippi River populations. Within the M. aestivalis complex, there are only two examples of geographic overlap among mtDNA phylogroups. One involves co-occurrence of the highly divergent M. marconis and M. cf. hyostoma, and the other is the detection of the apparently anthropogenic occurrence of mitochondrial DNA from a Red River form, either M. cf. hyostoma or M. australis, in the Cimarron River of the Arkansas River basin.
目前所认定的北美鱼类属Macrhybopsis（硬骨鱼纲：鲤科）包含12个物种，分布于北美东部大部分内陆地区。线粒体ND2基因和核S7内含子1的变异揭示了更深节点的基因树关系存在冲突，这些冲突被认为代表了过去的基因渗入和异源线粒体固定。结果支持广泛分布的estivalis复合体的单系性，其与gelida、meeki和storeriana存在连续的姐妹关系。Macrhybopsis目前的物种水平分类法总体上得到支持。形态上独特的australis和tetranema的物种地位得到支持，这两个物种都在基因上被hyostoma渗入。结果与之前关于广泛分布的hyostoma包含隐存物种的观点一致。对于采样不足的storeriana也显示出类似的隐存性；来自珠江的一个样本与两个密西西比河种群的ND2差异为8%。在estivalis复合体中，mtDNA系统发育组之间只有两个地理重叠的例子。一个涉及高度分化的marconis和cf. hyostoma的共存，另一个是在阿肯色河流域的锡马龙河中检测到来自红河种群（cf. hyostoma或australis）的明显人为引入的线粒体DNA。
