Matoso Daniele Aparecida, da Silva Hallana Cristina Menezes, Ferreira Júnior Augusto Luiz, Porto-Foresti Fábio, Utsunomia Ricardo, do Prado Fernanda Dotti, Artoni Roberto Ferreira
Departamento de Genética, Universidade Federal do Amazonas, Manaus, Amazonas, Brazil.
Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.
PeerJ. 2025 Mar 28;13:e18193. doi: 10.7717/peerj.18193. eCollection 2025.
The genus , which includes large-sized freshwater pimelodid species, is endemic to the southeastern coastal drainages of South America, specifically the Paraná River and Uruguay River basins.
In this study, genetic analyses of mitochondrial DNA (mtDNA) D-loop were conducted on four species within this genus across their respective distributions: (from the Tibagi and Uruguay rivers), (from the Iguaçu River), (from the Doce River), and (from the Paraíba do Sul River). and were employed as outgroups, and the topology was inferred using Bayesian Inference (BI) and maximum likelihood (ML) phylogenetic reconstruction techniques. Additionally, the sequences were analyzed to assess genetic diversity levels.
In contrast to the remaining species, which exhibited distinct species-specific clades, our data suggests that formed two sister clades, potentially representing distinct operational taxonomic units. Novel haplotypes were identified for each of the four species, further supporting the conclusions derived from the phylogenetic analysis. Overall, species displayed high haplotype diversity paired with low nucleotide diversity, indicating a demographic expansion event after reduced effective population size. Nevertheless, genetic structure indexes were notably high. These findings suggest that the genetic diversity within these species may be underestimated, which has implications for both taxonomic classification and biological conservation strategies.
In conclusion, the study of genetic diversity in four species has revealed distinct molecular operational taxonomic units (MOTUs), which highlights the necessity for conservation efforts. The detection of new haplotypes and intraspecific variability emphasizes the urgency of implementing systematic conservation measures in the face of looming extinction threats.
该属包括大型淡水油鲶科物种，是南美洲东南沿海流域的特有物种，具体分布于巴拉那河和乌拉圭河流域。
在本研究中，对该属内四个物种在其各自分布范围内进行了线粒体DNA（mtDNA）D环的遗传分析：（来自蒂巴吉河和乌拉圭河）、（来自伊瓜苏河）、（来自多西河）和（来自南帕拉伊巴河）。和被用作外类群，并使用贝叶斯推断（BI）和最大似然（ML）系统发育重建技术推断拓扑结构。此外，还对序列进行了分析以评估遗传多样性水平。
与其余表现出明显物种特异性分支的物种不同，我们的数据表明形成了两个姐妹分支，可能代表不同的操作分类单元。为这四个物种中的每一个都鉴定出了新的单倍型，进一步支持了系统发育分析得出的结论。总体而言，物种表现出高单倍型多样性和低核苷酸多样性，表明在有效种群大小减少后发生了种群扩张事件。然而，遗传结构指数显著较高。这些发现表明这些物种内的遗传多样性可能被低估，这对分类学分类和生物保护策略都有影响。
总之，对四个物种遗传多样性的研究揭示了不同的分子操作分类单元（MOTUs），这突出了保护工作的必要性。新单倍型和种内变异性的发现强调了面对迫在眉睫的灭绝威胁实施系统保护措施的紧迫性。
