Two new species of cichlid fish have been discovered in Lake Victoria, Tanzania by scientists from the Naturalis Biodiversity Center and the Institute of Biology Leiden, the Netherlands.
The scientists discovered the two species after analyzing data from a 1985 survey that was conducted by Dr. Tijs Goldschmidt of the Institute of Biology Leiden to determine the status of the Lake Victoria cichlids, which at the time were declining in the lake. Both Haplochromis argens and Haplochromis goldschmidti closely resemble each other but have different noses, mouths, and a slight difference in coloration. In addition, H. argens is more common to Mwanza Gulf on the lake while H. goldschmidti is found in Emin Pasha Gulf.
Haplochromis argens was common in the lake up until 1985 while Haplochromis goldschmidti was first observed in the lake in 1985-86. This time period coincides with the rise of Nile perch, which decimated large populations of herbivorous foraging fish, including Haplochromis argens, which became very rare in the lake from 1987-1992. At the time of the study, Goldschmidt was studying speciation, the biological process in which a new species arises, but never described the two fish taxonomically.
Today, there has been a resurgence of cichlids in the lake and the two new species are described in Zookeys, of which the full description and paper can be found here.
For a more detailed descirption of the rise of the Nile perch and demise of the cichlids of Lake Victoria, read the article by Paul V. Loiselle, Lake Victoria.