Genomic data support the taxonomic validity of Middle American livebearers Poeciliopsis gracilis and Poeciliopsis pleurospilus (Cyprinodontiformes: Poeciliidae)

Poeciliopsis (Cyprinodontiformes: Poeciliidae) is a genus comprised of 25 species of freshwater fishes. Several well-known taxonomic uncertainties exist within the genus, especially in relation to the taxonomic status of Poeciliopsis pleurospilus and P. gracilis. However, to date, no studies have been conducted to specifically address the taxonomic status of these two species. The goal of this study was to examine the taxonomic validity of P. pleurospilus and P. gracilis using genomic data (ddRADseq) in phylogenetic, population genetic, and species delimitation frameworks. Multiple analyses support the recognition of both taxa as distinct species and also permits us to revise their respective distributions. A species delimitation analysis indicates that P. pleurospilus and P. gracilis are distinct species from one another, each of which consists of two distinct lineages that are geographically structured. Phylogenetic and population genetic analyses demonstrate clear evidence that indiv...

花鳉属（*Poeciliopsis*，隶属于鳉形目Cyprinodontiformes花鳉科Poeciliidae）是一个包含25种淡水鱼类的属。该属内存在多项长期悬而未决的分类学争议，尤以侧斑花鳉（*P. pleurospilus*）与纤细花鳉（*P. gracilis*）的分类地位问题最为突出。截至目前，尚无专门针对这两个物种分类地位的研究发表。本研究旨在利用双酶切限制性位点关联DNA测序（ddRADseq，double-digest restriction site-associated DNA sequencing）的基因组数据，分别从系统发育、种群遗传与物种界定三个分析框架，验证侧斑花鳉与纤细花鳉的分类有效性。多项分析结果均支持将二者认定为独立物种，同时还可修订其各自的分布范围。物种界定分析显示，侧斑花鳉与纤细花鳉互为独立物种，且二者内部均各存在两个具有地理结构的演化支系。系统发育与种群遗传分析清晰证实，个体……