Comparative morphology of the oropharyngeal cavity of clinid fish (Perciformes: Clinidae), with particular attention to the form, number and distribution of taste buds, and dentition

Abstract

The present study compares the form, number and distribution of taste buds (TB) in the oropharyngeal cavity (OC) of 17 species of clinid fish (Perciformes, Blennioidei, Clinidae) from different geographical regions (Australia, Taiwan, South Africa), and includes observations on dentition. Larger juveniles and adult clinids possess the three types of TB described in teleost fish: Type I, protruding on papillae, dominate the anterior OC, often together with the less protruding Type II, whereas Type III, whose apical parts are level with the oral epithelium, dominate the posterior OC, closer to the pharynx. The average surface diameter of a TB is approx. 4μm, but some TB of 1.5μm were also observed. High numbers of TB are situated on and around the toothed epipharyngeal and hypopharyngeal bones, possibly serving as the final checkpoint of food items. The total number of TB in the various species ranges from 648 in Heteroclinus wilsoni of 35mm SL and 977 in a 54mm SL adult Muraenoclinus dorsalis, to 2 526 in Heteroclinus heptaeolus of 74mm SL and 4 050 in a 118mm SL Clinus superciliosus. In specimens of the same species the number of TB is positively correlated with fish size, but there appears to be no such correlation between different taxa. The highest density of TB (216 mm⁻²) was observed on the hypopharyngeal bones of Clinus superciliosus, and the lowest (8.4 mm⁻²) on the upper valve of Clinus cottoides. The number and distribution of TB in clinids are compared with data from other fish taxa.