Although several species of Ancistrus have been described from the Amazon and Paraguay river basins in the states of Amazonas and Mato Grosso, Brazil, the taxonomic status of most specimens from these regions remains doubtful. In the present work, cytogenetic and molecular data were used to discriminate and isolate unexpected Ancistrus lineages from the Amazon and Paraguay basins. For that, it was used DNA barcoding based on mitochondrial Cytochrome Oxidase Subunit I (COI) gene and cytogenic data to perform such molecular discrimination. The analyzed sequences had 669 bp, of which 171 bp were conserved and 491 bp were variable. The Neighbor-joining and Bayesian analysis revealed 21 distinct groups in topology. The genetic distances within each group was 0.4%, 21 times smaller than the mean distance observed among groups, which was 8.4%. These values showed seven distinct lineages of Ancistrus from the studied points of the Amazon basin and eight lineages from the Paraguay basin points. Our results illustrate the efficiency of this technique for the discrimination of the Ancistrus lineages once it indicates the occurrence of cryptic species in these regions, which cannot yet be identified either with just chromosomal or morphological analyzes.

尽管已经从巴西亚马逊州和巴西马托格罗索州的亚马逊河和巴拉圭流域描述了几种Ancistrus种类，但是来自这些地区的大多数标本的分类学地位仍然令人怀疑。在目前的工作中，使用细胞遗传学和分子数据来区分和分离出意外的Ancistrus来自亚马逊和巴拉圭盆地的血统。为此，使用基于线粒体细胞色素氧化酶亚基I（COI）基因和细胞遗传学数据的DNA条形码进行这种分子识别。分析的序列有669 bp，其中171 bp是保守的，而491 bp是可变的。邻居连接和贝叶斯分析揭示了21个不同的拓扑组。每组内的遗传距离为0.4％，比各组间平均距离的8.4％小21倍。这些值显示了来自亚马逊盆地研究点的七个Ancistrus谱系和来自巴拉圭盆地点的八个谱系。我们的结果说明了该技术对Ancistrus判别的效率 谱系一旦表明在这些区域中存在隐性物种，就不能仅通过染色体或形态学分析来识别它们。