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

Cichlids from the tribe Eretmodini, endemic to Lake Tanganyika, provide a u nique example of diet-associated differences in dentition (especially tooth shape) within a group of closely related species. Here, we examine the too th pattern and sequence of tooth replacement in four representative eretmod ine taxa, as a starling point of a new study that will focus on the mechani sms 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 (d ifferent spacing of newly developing germs) is necessary to produce the dif ferent dental arcades observed in eretmodine cichlids. The position and sta te of development of the replacement teeth, as well as localized growth and resorption of the jaw bone, add histological evidence in support of the re placement pattern described for the four taxa. The tooth replacement patter n proposed here is uncommon among teleosts.