Abstract:
The nucleotide sequences of the first internal transcribed spacer (ITS-1) of the ribosomal RNA gene
cluster have been determined for 11 species of closely
related endemic cichlid fishes of the Lake Victoria
region (LVR) and 6 related East African cichlids. The
ITS-1 sequences confirmed independently derived basal
phylogenies, but provide limited insight within this
species flock. The line leading to Pseudocrenilabrus
multicolor arose early, close to the divergence event
that separated the tilapiine and haplochromine tribes
of the ‘‘African Group’’ of the family Cichlidae. In this
phylogeny, Astatoreochromis alluaudi and the riverine
Astatotilapia burtoni are sister taxa, which together
are a sister group to a monophyletic assemblage including both Lake Victoria and Lake Edward taxa. The
ITS-1 data support the monophyly of haplochromine
genera across lakes. Since Lake Victoria is believed to
have been dry between 14,500 and 12,400 BPE, the
modern assemblage must have been derived from reinvasion by the products of earlier cladogenesis events.
Thus, although the regional superflock is monophyletic, the haplochromines of Lake Victoria itself did
not evolve in situ from a single ancesto