Statolith identification of Mediterranean Octopodidae, Sepiidae, Loliginidae, Ommastrephidae and Enoploteuthidae based on warp analyses

The statoliths of 14 species (193 right statoliths from subadult to adult individuals), belonging to five Cephalopoda families (Sepiidae, Loliginidae, Enoploteuthidae, Ommastrephidae and Octopodidae) were analysed using morphometric methods based on landmarks (geometric morphometry). The aim of the current study is to determine the discriminating power of statolith shape analysis in species identification of Mediterranean cephalopods. Discriminant analyses of the partial warps were able to fully identify (100% discrimination) the species of all families, except Octopodidae which showed some misclassification (correctly classified about 68-90%). These results were also shown by relative warp analysis. Octopodidae statoliths were studied for the first time using geometric landmark-based methods. Greatest differences in statolith shape between Octopodidae species, were in the area that unites the statolith dome with the flat wing. Landmark analysis applied to statoliths can be a useful taxonomic tool in the identification of closely related species.