Comparison of taste bud form, number and distribution in the oropharyngeal cavity of lizardfishes (Aulopiformes, Synodontidae)

The present study compares the distribution, form and number of taste buds (TB) in the oral cavity of several species of lizardfishes (Synodontidae) belonging to the genera Saurida, Synodus and Trachinocephalus, from various regions. The oral cavities of the studied lizardfishes are occupied by dense rows of sharp teeth, leaving bare only small areas of the epithelium, on which the TB are exposed. In all the studied species, groups of type I and type II TB predominate, protruding on skin-papillae featuring groups of sensory cells, 3-5 µm in diameter. Fewer types III TB are found, mostly adjacent to the pharyngeal region. The TB in the frontal part of the oral cavity are situated on lamellae between the teeth on the anterior part of the upper and lower jaws, with rows of single TB along the interior sides of the jaws. Small numbers of TB are also found on the basibranchials of the 3rd and 4th gill arches and the ceratobranchials of the 4th arch. in the studied species, the total number of TB in the oral cavity range between 458 (± 30) in Synodus dermatogenys to 1738 (± 120) in S. variegatus, small in number compared to fishes of the same dimensions belonging to other systematic groups. The oral sensory area thus formed by the exposed surfaces of the sensory cells range between 8,976 µ[m.sup.2] in S. dermatogenys to 34,064 µ[m.sup.2] in S. variegatus, compared to circa 300,000 µ[m.sup.2] in some cichlid fishes. It would thus appear that lizardfish predation on larger prey, such as other fishes, relies more on visual detection, while chemical oral recognition (gustatory) of engulfed prey possibly plays a secondary role. La presente etude compare la distribution, la forme et le nombre de papilles gustatives (PG) de la cavite buccale de plusieurs especes de poissons lezards (Synodontidae) appartenant aux genres Saurida, Synodus et Trachinocephalus, et provenant de diverses regions. Les cavites orales des poissons lezards examines sont occupees par des rangees serrees de dents tranchantes, ne laissant que tres peu de zones nues sur lesquelles les papilles gustatives (PG) sont exposees. Chez toutes les especes etudiees, les groupes de PG de type I et type II predominent a la surface des papilles, avec des groupes de cellules sensorielles de 3-5 [micron]m de diametre. Quelques PG de type III ont ete decouvertes, la plupart adjacentes a la region pharyngee. Les PG situees dans la partie frontale de la cavite buccale sont localisees sur les lamelles entre les dents