Frequency distribution of vertebra number among 294 species of Gobiidae occurring in Japan. Data are based on Akihito et al. (1984) and this study. Following the phylogenetic results of Thacker (2003), Gunnellichthyidae sensu Akihito et al. (1984) is included in Gobiidae. The genetically differentiated taxa uncovered by the Cyt b phylogeny are scored individually in the histogram. Interstitial species are indicated by black bars.