Data from: Barcoding snakeheads (Teleostei, Channidae) revisited: discovering greater species diversity and resolving perpetuated taxonomic confusions

Snakehead fishes of the family Channidae are predatory freshwater teleosts from Africa and Asia comprising 38 valid species. Snakeheads are important food fishes (aquaculture, live food trade) and have been introduced widely with several species becoming highly invasive. A channid barcode library was recently assembled by Serrao and co-workers to better detect and identify potential and established invasive snakehead species outside their native range. Comparing our own recent phylogenetic results of this taxonomically confusing group with those previously reported revealed several inconsistencies that prompted us to expand and improve on previous studies. By generating 343 novel snakehead coxI sequences and combining them with an additional 434 coxI sequences from GenBank we highlight several problems with previous efforts towards the assembly of a snakehead reference barcode library. We found that 16.3% of the channid coxI sequences deposited in GenBank are based on misidentifications. With the inclusion of our own data we were, however, able to solve these cases of perpetuated taxonomic confusion. Different species delimitation approaches we employed (BIN, GMYC, and PTP) were congruent in suggesting a potentially much higher species diversity within snakeheads than currently recognized. In total, 90 BINs were recovered and within a total of 15 currently recognized species multiple BINs were identified. This higher species diversity is mostly due to either the incorporation of undescribed, narrow range, endemics from the Eastern Himalaya biodiversity hotspot or the incorporation of several widespread species characterized by deep genetic splits between geographically well-defined lineages. In the latter case, over-lumping in the past has deflated the actual species numbers. Further integrative approaches are clearly needed for providing a better taxonomic understanding of snakehead diversity, new species descriptions and taxonomic revisions of the group.鳢科（Channidae）蛇头鱼为分布于非洲与亚洲的掠食性淡水真骨鱼（teleosts），目前已确认38个有效物种。蛇头鱼是重要的食用鱼类，广泛应用于水产养殖与活体水产贸易，且已被广泛引种，其中多个物种已成为极具入侵性的类群。近期，Serrao及其团队构建了鳢科鱼类的条形码数据库，旨在更精准地检测和识别原生分布范围之外的潜在入侵及已定植的蛇头鱼物种。将本团队近期针对这一分类学疑难类群的系统发育研究结果与已有文献报道的结果进行比对后，我们发现了多处不一致之处，这促使我们对既往研究进行拓展与优化。本研究新生成了343条蛇头鱼细胞色素c氧化酶亚基I（coxI）序列，并将其与基因银行（GenBank）数据库中额外的434条coxI序列进行整合，由此揭示了既往在构建蛇头鱼参考条形码数据库过程中存在的若干问题。我们发现，GenBank数据库中提交的鳢科coxI序列里，有16.3%的序列基于错误的物种鉴定结果。然而，通过纳入本团队的研究数据，我们得以解决这些长期存在的分类学混淆问题。本研究采用的多种物种界定方法（BIN、GMYC与PTP）均一致表明，蛇头鱼的潜在物种多样性远高于当前已被认知的水平。本研究共得到90个BIN，且在15个当前已被认可的物种中，均鉴定出多个BIN。这种更高的物种多样性主要源于两方面：一是纳入了东喜马拉雅生物多样性热点区中尚未被描述的狭域特有物种；二是纳入了多个广泛分布的物种，这些物种在地理分区明确的支系间存在深度遗传分化。在后一种情况中，既往研究中的过度归并导致实际物种种数被低估。显然，未来需要采用更多整合性研究方法，以更好地厘清蛇头鱼的分类学多样性、开展新物种描述以及对该类群进行分类学修订。