Telmatochromis temporalis Magara. Photo by Ad Konings
A study of Telmatochromis temporalis by the University of Bristol has shown that competition plays a role in the evolution of new species. T. temporalis is an endemic cichlid from Lake Tanganyika. According to the study, the larger T. temporalis drive the smaller temporalis away from the preferred rocky habitat. The smaller T. temporalis are forced to build their homes in shells along the sand. The competition for the preferred habitat has separated the two groups of fish. Once separated, the two groups will only breed among themselves. This separation opens the door for different evolutionary paths. Ad Konings has always considered T. sp. "temporalis shell" to be a morph of the original T. temporalis.
A video by one of the authors of the study explains the process:
A quick synopsis of the study can be found on the International Science Times website.
More information on the smaller variant can be found in the Telmatochromis sp. "Temporalis Shell" article by Brett Harrington.
Telmatochromis temporalis mbita. Photo by Ad Konings