Dermal sense organs and their significance in the feeding behaviour of the common sole Solea vulgaris

Abstract

Light and electron microscopic studies on dermal sense organs of the sole Solea vulgaris Quensel, 1806 reveal that the sensory buds – located in large numbers between the papillae, mainly on the abocular side of the fish – are certainly free neuromasts. It is suggested that these papillae serve as protectors for the sensitive neuromasts rather than as sensory organs. They may improve the perception function of the neuromasts for mechanical stimuli. Taste buds, in different distributions, were found only in oral cavity, pharynx, on gill rakers, and on lips. The lateral line system, though partly asymmetrical, is highly developed on both the ocular and abocular sides of the fish. The nasal sac of the abocular side is smaller in size and contains fewer lamellae than that of the ocular side of the fish. Ocular and abocular nasal sacs are connected via an accessory sac. Results indicate the significance of mechanoreceptors for the feeding behaviour of post-metamorphosed sole which are known to feed most actively at night and until now have been thought to detect food primarily by means of chemoreception.