Documentation of shared spawning arenas between Enantiopus melanogenys and Xenotilapia ochrogenys

Pierre Brichard was the first to observe and report on the peculiar phenomena of simultaneous breeding in the same arena by the sand-dwelling species Enantiopus melanogenys and Xenotilapia ochrogenys (Brichard 1978). Males of both species were seen digging out their sand-scrape spawning sites without interfering with its other, and at no point aggression were noted between the two species, each engaging in their own activities. The spawning sites of the two were found to be mixed over the entire area observed, while females of both species were circling together over the displaying males, recognizing conspecific males by their coloration and display, but likely also by the shape of the spawning sites: male Enantiopus melanogenys dig large saucer shaped spawning sites, while the spawning sites of Xenotilapia ochrogenys are characterized by numerous small heaps of sand set in circle around a small depression (Brichard 1989).

This interesting behavior was recently documented for the first time on the above photo taken in the area of Maswa (Tanzania) by Juan Molina during a trip to Lake Tanganyika. In the foreground of the photo can be seen the saucer-shaped spawning sites of Enantiopus melanogenys, and in the back three spawnings sites (one on the left side and two on the right side of the photo) with small heaps of sand has been constructed by Xenotilapia ochrogenys males.

The fact that the reproduction of Enantiopus melanogenys and Xenotilapia ochrogenys take place at such close quarters, give food for thought on the origin of the potentially undescribed Enantiopus sp. "kilesa". As suggested by Konings this species may be of hybrid origin, as it seems to be somewhat intermediate between Enantiopus melanogenys and Xenotilapia ochrogenys, both in terms of coloration and morphology, as well as in the construction of sand-scrape spawning sites, which appear to be a mixture of that performed by the other two species (Konings 1998). Unfortunately Enantiopus sp. "kilesa" has not been included in any of the phylogenetic analysis performed in recent years, be it morphological or molecular, so a hint on its relationship is not available, but the above documentation of shared spawning arenas between Xenotilapia ochrogenys and Enantiopus melanogenys certainly give some credibility to the scenario that it is a natural hybrid, stabilized along the western shore of Lake Tanganyika between Kalamie and the Kavala Islands in DR Congo.