A single tooth replacement pattern generates diversity in the dentition in cichlids of the tripe Eretmodini, endemic to Lake Tanganyika (Teleostei : Cichlidae)

Cichlids from the tribe Eretmodini, endemic to Lake Tanganyika, provide a unique example of diet-associated differences in dentition (especially tooth shape) within a group of closely related species. Here, we examine the tooth pattern and sequence of tooth replacement in four representative eretmodine taxa, as a starling point of a new study that will focus on the mechanisms responsible for ontogenetic and phylogenetic divergence of tooth shape. New teeth are formed in adjacent positions labial to but alternating with older ones in waves that sweep from mesial to distal. Only a minor shift (different spacing of newly developing germs) is necessary to produce the different dental arcades observed in eretmodine cichlids. The position and state of development of the replacement teeth, as well as localized growth and resorption of the jaw bone, add histological evidence in support of the replacement pattern described for the four taxa. The tooth replacement pattern proposed here is uncommon among teleosts.