Meeting Abstract
Some teleosts species have elongate and projecting structures on their heads that have been called barbels or cirri. Barbels have been well studied and are described as sensory structures in Siluriformes and Acipenseriformes. Cirri functions are characterized differently among teleost fish groups. In the current study, we investigate the functional morphology of the cirri on five species within Cottoidae (Blepsias cirrhousis, Clinocottus globiceps, Jordania zonope, Nautichthys oculofasciatus, Oligocottus rimensis). Cirri in these species represent morphological diversity, ranging from few to numerous and simple to ornate. This study addresses the following questions: (1) What are the morphological and histological components of cirri? and (2) What functions do cirri serve? Examination of cleared and stained specimens suggest that the cirri in three of these five species are supported by cartilaginous rods. Using scanning electron microscopy, we observed structures on the cirri and nasal pores of these species with morphology similar to that of the taste buds documented in the barbles of Siluriformes and Acipenseriformes. Interestingly, taste bud morphology varied among the five species studied here and warrants further histological investigation. Differences in structure and function of cirri found across the five species may be due to variable ecology and habitat — where they may serve lesser or more significant roles. Because cirri are often used to describe and differentiate among species in Cottoidae as well as in other groups with similar structures, elucidating the functional morphology of cirri in this group will help determine their value as characteristics for morphometric and systematic studies.
