Box plot of premaxilla to preoperculum length as % of SL, totally 518 specimens 116-208 mm SL. Number of specimens is given for each sample separately. Samples in bold are detailed in Table 1. Additional samples given in capital letters (Delling, unpublished) refer to rivers or streams in the given regions (Table S1). Ezenam is a lake in Daghestan and labrax represents trout from Black Sea basin with an anadromous silvery and slender appearance. Turkey and Mediterranean are samples scattered in the regions. Boxes represent median value +/− 25% of the observations, and whiskers the inner fences. Asterisks are outside or far outside values.