In a recent issue of the journal Zootaxa, researchers Gertrud Konings-Dudin, Adrianus Konings and Jay Stauffer have described and named three new species of cichlid from the genus Melanochromis; two of them being fairly widespread among aquarists keeping African cichlids.
All three species hail from the eastern shore of Lake Malawi and belong to the group commonly referred to as Mbuna cichlids among fish keepers.
The fish you may have been offered under the name Melanochromis sp. “northern blue” (picture here) has been given the full name Melanochromis kaskazini. Just like its old trade name suggests, this Malawi cichlid hails from the northern part of the lake and the word kaskazini was choosen since it is the Kiswahili word for “northern”. (Kiswahili, also known as Swahili, is an African language spoken along the continent’s eastern coast.)
The “blue” part of its old trade name is a reference to the colour of the males; they are cobalt blue, while the females are white with a yellow or orange anal fin. Melanochromis kaskazini looks quite similar to its close relative Melanochromis lepidiadaptes but the latter one sports a suit of mensural characters not seen in Melanochromis kaskazini.
The Mbuna cichlid previously sold in fish stores as Melanochromis sp. “auratus elongate” (picture here) is from now named Melanochromis mossambiquensis. The fish is named after the country Mazambique since it is found along the Mazambique shore of Lake Malawi; a lake shared between the countries Mazambique, Malawi and Tanazania.
In Melanochromis mossambiquensis, the female fish is adorned with yellow stripes on the belly and a midlateral and dorsolateral black stripe that is narrower than the submarginal black band in the dorsal fin. The yellow stripes do not cover the entire lower abdomen, and the caudal fin features black spotting. The male fish is brown/black with white dorsolateral and midlateral stripes, and he displays a suite of mensural characters.
The third Mbuna cichlid, which does not have any trade name, has been given the scientific name Melanochromis wochepa due to its small size. Wochepa means “small” in Chinyanja, also known as Chichewa, a Bantu language spoken in south-central Africa. I have not been able to find a picture at this time.
Melanochromis wochepa males are blue without any white striping, while the females sport a submarginal dorsal band that is wider than the mid-lateral and the dorsolateral stripe, thin abdominal yellow stripes never covering the entire lower abdomen, and a suite of mensural characters. The vomer is steep-angled in both sexes.
For more information, see paper published in Zootaxa: Konings-Dudin, G, AF Konings and JR, Jr Stauffer (2009) Descriptions of three new species of Melanochromis (Teleostei: Cichlidae) and a redescription of M. vermivorus. Zootaxa 2076, pp. 37–59.