Discovery of Xenotilapia sp. ’papilio sunflower’ at the area of Cape Chaitika, Zambia

Xenotilapia sp. 'papilio sunflower' wild adult collected at Cape Chaitika, Lake Tanganyika [Zambia], in the aquarium of Marta Mierzenska and Robert Mierzenski, Krakow [Poland]. Photo by Thomas Andersen. (2013-04-20). determiner Thomas Andersen

This spring two shipments has been imported into Europe, one to Poland and one to Germany, containing Xenotilapia sp. ‘papilio sunflower’ reportedly collected at Cape Chaitika, Zambia. The natural distributional range of this potentially undescribed species has been thought to encompass the coastline between Chituta Bay in Zambia and Cape Mpimbwe on the Tanzanian coast (Konings 1998). It is thus surprising to find this species at Cape Chaitika, which is over 40 km in a straight line from Chituta Bay and over 60 km if following the contours of the coastline. It is even more surprising when considering the fact that the area of Cape Chaitika has been well explored, and no X. sp. ‘papilio sunflower’ has ever been reported from this locality before.

The immediate reactions to these imports (myself included) were, that they must either be the result of an incorrect information on the place of collection or, on a much more serious matter, that Xenotilapia sp. ‘papilio sunflower’ had been introduced at Chaitika. Against the latter scenario spoke the many exported individuals; if introduced one would not expect a population to be able to establish itself so quickly. The exporter maintained that the fish were caught at Cape Chaitika and there were really no reason not to believe this, as the company is known to be reliable and thorough with the information on collection localities. The divers could have played a trick though, as they might have collected them elsewhere, and renamed them - but to what purpose?

Xenotilapia sp. 'papilio sunflower' wild adult reportedly collected at Cape Chaitika, Lake Tanganyika [Zambia], in the aquarium of Marta Mierzenska and Robert Mierzenski, Krakow [Poland]. Photo by Thomas Andersen. (2013-04-20). determiner Thomas Andersen

The puzzle were quickly solved though, when Heinz Büscher could inform us that Xenotilapia sp. ‘sunflower’ were indeed present in the vicinity of Cape Chaitika, as he already discovered it in 2005 – in fact he found it to be present on a stretch of coastline no less than 10 km long (Heinz Büscher, personal communication), making the scenario of an introduction highly unlikely. That X. sp. ‘papilio sunflower’ is present on this stretch of coast is in fact not as odd as it may seem, when having the massive fluctuations of Lake Tanganyika’s lake-level into mind. In the Lake’s earlier history when the lake-level were lower, the area of Chaitika would have been connected with the coast in southern Tanzania and could have harbored a continuous population, which were later split with a rising lake-level.

Map of the southern part of Lake Tanganyika with the localities mentioned in the text, as well as the 200 meter depth contour line, showing that the area of Cape Chaitika has been connected with southern Tanzania at a lower lake-level.

The known distribution of Xenotilapia sp. ‘sunflower’ is thus enlarged markedly, and it would be interesting to further investigate if more undiscovered populations are present, e.g. along the Ulungu escarpment towards Katoto – Lake Tanganyika still have a lot of surprises to be discovered!