Catfishes from the North-Western Part of Lake Tanganyika: Contribution to a Reference Library of DNA Barcodes

In spite of the global barcoding effort, there is still a lack of genetic data on African freshwater fishes. We aimed to contribute to bridging this gap by providing molecular data on commercially important catfish species from the north-western part of Lake Tanganyika. We collected 215 catfish specimens and sequenced the standard vertebrate barcoding gene (COI) for 41 specimens. Additionally, we sequenced 20 specimens for the mitochondrial Cyt-b gene to make the link to previously published datasets. We identified 11 species using morphology, compared DNA sequences with those available on GenBank, and employed Automatic Barcode Gap Discovery (ABGD) and phylogenetic approaches. The dataset includes the first molecular data (COI and Cyt-b) for Chrysichthys acsiorum, as well as the first-ever COI sequences for Dinotopterus cunningtoni and Malapterurus tanganyikaensis. Our findings extend the known distribution of C. acsiorum by approximately 100 km. Additionally, we demonstrated the difficulty in delineating species of Chrysichthys and Synodontis from Lake Tanganyika with molecular tools. For Chrysichthys, automated methods, such as ABGD, failed to delineate species. However, barcoding does seem promising as all the individual species are resolved as clades. Within Synodontis, the study found a strong similarity between S. grandiops and S. multipunctatus, highlighting a need for revision. Our findings emphasize the necessity for integrative taxonomy in the study of catfishes from Lake Tanganyika.