Tooth Shape Differences Analyzed by Biometric and Morphometric Approaches: A Case Study on Two Morphologically Very Similar Lacustrine Cichlid Species

Tooth shape is generally considered to be under strong genetic control, and highly species specific. It is therefore widely used for taxonomic studies. The tooth shape-based morphological classification of the Eretmodini (a tribe of closely related cichlids endemic to Lake Tanganyika), has, however, been shown to be in conflict with recent molecular data, which suggests the occurrence of parallel evolution. A detailed biometric and morphometric analysis of tooth shape has been undertaken for two genetic lineages of the taxon Eretmodus cyanostictus . The use of both landmark-based measurements and elliptic Fourier analysis reveals differences between both lineages and supports the molecular phylogeny. These differences further endorse the interpretation of parallel evolution. In addition, we here present a powerful tool for the analysis of tooth shape.