Morpho-anatomy of the otic region in carapid fishes: eco-morphological study of their otoliths

Carapid species are characterized by so-called otophysical structures (soni c muscles, broad first apophyses covering the anterior part of the swimblad der. etc.) The family includes pelagic (Pyramodon and Snyderidia) and benth ic (Echiodon) species and ones that are either commensal with (Onuxodon, Ca rapus) or parasites of (Encheliophis) invertebrates (sea cucumbers, etc). T he aim of the present work was to seek possible relationships between the s tructures of the inner ear (particularly the sagitta) on the one hand and o tophysical structures and lifestyles within the Carapidae family. In the ei ght species studied. the otic cavity is wide, the saccular otosac and its s agitta are particularly developed. The sacculi touch each other on the medi an line. A comparison of the inner ear structures reveals notably that the species with the most developed sagitta and sacculus are those with the lar gest parapophyses and have a commensal or parasitic lifestyle. (C) 2001 The Fisheries Society of the British Isles.