Grupo de Biotaxonomía Morfológica y Molecular de Peces (BIMOPE), Instituto de Investigaciones Marinas y Costeras (IIMyC, CONICET-UNMDP), Funes 3350, Mar del Plata 7600, Argentina.
Mol Ecol Resour. 2012 Nov;12(6):999-1011. doi: 10.1111/1755-0998.12010. Epub 2012 Sep 17.
The fish fauna of the Pampa Plain, the southernmost distribution range of many Neotropical species, was barcoded in this study. COI sequences were analysed by means of distance (K2P/NJ) and character-based (ML) models, as well as the Barcode Index Number (BIN). K2P/NJ analysis was able to discriminate among all previously identified species while also revealing the likely occurrence of two cryptic species that were further supported by BIN and ML analyses. On the other hand, both BIN and ML were not able to discriminate between two species of Rineloricaria. Despite the small genetic divergence between A. cf. pampa and A. eigenmanniorum, a tight array of haplotypes was observed for each species in both the distance and character-based methods. Deep intraspecific divergences were detected in Cnesterodon decemmaculatus (5%) and Salminus brasiliensis (6%). For Salminus brasiliensis, these findings were further supported by character-based (ML) evidence and meristic and morphological data. Our results also showed that Pampa Plain representatives of Salminus brasiliensis, Rhamdia quelen, Hoplias malabaricus, Synbranchus marmoratus, Australoheros facetus, Oligosarcus jenynsii and Corydoras paleatus differed by more than 3% from their conspecifics from other parts of South America. Overall, this study was able to highlight the likely occurrence of a cryptic species in Salminus brasiliensis and also illustrate the strong geographical structure in the COI sequence composition of seven fish species from South America.
本研究对巴西南潘帕斯平原（许多新热带物种最南端的分布范围）的鱼类区系进行了 DNA 条码分析。通过距离（K2P/NJ）和基于特征（ML）的模型以及条码指数（BIN）对 COI 序列进行了分析。K2P/NJ 分析能够区分所有已识别的物种，同时还揭示了两种隐存物种的可能存在，这些物种还得到了 BIN 和 ML 分析的进一步支持。另一方面，BIN 和 ML 均无法区分 Rineloricaria 的两个物种。尽管 A. cf. pampa 和 A. eigenmanniorum 之间的遗传差异很小，但在距离和基于特征的方法中，每个物种都观察到了紧密的单倍型排列。在 Cnesterodon decemmaculatus（5%）和 Salminus brasiliensis（6%）中检测到了深的种内分歧。对于 Salminus brasiliensis，这些发现还得到了基于特征（ML）证据以及可数和形态数据的支持。我们的研究结果还表明，巴西南潘帕斯平原的 Salminus brasiliensis、Rhamdia quelen、Hoplias malabaricus、Synbranchus marmoratus、Australoheros facetus、Oligosarcus jenynsii 和 Corydoras paleatus 与来自南美洲其他地区的同种鱼类之间的差异超过 3%。总的来说，本研究能够突出 Salminus brasiliensis 中可能存在隐存种，并且还说明了来自南美洲的 7 种鱼类 COI 序列组成中存在强烈的地理结构。
