Xenotilapia nigrolabiata vs. Xenotilapia sp. "Red Princess"

The "Red princess" is without doubt one of the greatest discoveries in Lake Tanganyika in several years, and as soon as the first specimens were brought to the surface, the discussions started as whether to regard it as new species or a geographical variant of an already described species.

Heinz Büscher examined a preserved specimen of the "Red Princess" (Büscher in Loose 2004), showing that the morphological traits fit the characteristics given by Max Poll in his description of Xenotilapia nigrolabiata (Poll 1951). Some inconsistencies appear though, when comparing the description of the coloration given by Poll and the coloration present in the "Red Princess" (Andersen 2007). Poll mentions nothing on the conspicuous red coloration in the dorsal and caudal fin, the hallmark of the "Red Princess", and the lips are described as being black, and not dark blue. Furthermore the females are described as being lesser coloured, showing only vague markings in the fins, which do not correspond with the coloration present in "Red Princess" females

During an examination of all specimens of Xenotilapia nigrolabiata present at the Africa Museum in Tervuren, Belgium (MRAC, Musée Royal de l’Afrique Centrale) including the ones used in type-serie, it was shown that all specimens to a varying degree had a reddish-brown coloration in the dorsal, corresponding with that present in the "Red Princess". Traces of blue on the lips was still visible in some specimens, and as dark blue turns black during preservation, it is safe to assume that a dark blue upperlip were present when the preserved specimen were still alive. The lesser coloration of females was not apparent, as females were found to have nearly the same coloration as similar sized males. It seems odd that these inconsistencies appear between Poll’s original description and the characteristics actually present in the type-serie. It is possible that Poll never saw freshly caught specimens, only newly preserved ones.

The conclusion of this examination was therefore that the "Red Princess" is indeed a geographical variant of Xenotilapia nigrolabiata, as first suggested by Büscher. (Andersen 2007).