Confirmation that Malagarasi sardine Engraulicypris spinifer is indigenous to the Lake Malawi/Nyasa/Niassa catchment

Lake Malawi/Nyasa/Niassa (LMNN) contains exceptional fish diversity with more than 800 species recognised, yet the rivers flowing into LMNN also contain a rich variety of fish species. Here, we report a study, using a combination of morphological and genetic evidence, that shows that the Malagarasi sardine Engraulicypris spinifer Bailey and Matthes, 1971 is present in the northern sector of the LMNN catchment. Previously, the species was only known from the Lake Rukwa, Rufiji River and Malagarasi River catchments. We found that individuals from the LMNN catchment possess the same mitochondrial COI haplotype as those in the Malagarasi River catchment, and that both groups share key diagnostic morphological traits of the species. These findings support theories of past hydrological connectivity between LMNN and the neighbouring Rukwa and Rufiji catchments. They also indicate potential for further discoveries of novel fish diversity in riverine habitats of the LMNN catchment.