Dentition, diet and behaviour of six gobiid species (Gobiidae) in the Caribbean Sea
Using scanning electron microscopy (SEM) the upper and lower jaw and for the first time the pharyngeal jaw apparatus were described in Coryphopterus dicrus (Böhlke & Robins, 1960), C. eidolon (Böhlke & Robins, 1960), C. thrix (Böhlke & Robins, 1960), C. tortugae (Jordan, 1904), C. venezuelae (Cervigón, 1966) and Gnatholepis thompsoni (Jordan, 1904). The dentition of all Coryphopterus species was found to be quite similar in arrangement, number and shape. Gnatholepis thompsoni differs from the other species in the number of teeth and their arrangement as well as in its pharyngeal jaw apparatus where the bones are morphologically distinct in the lower jaw. The latter had been observed in other species of Gnatholepis and could therefore be a synapomorphy for the genus. Additionally, stomach contents analy-ses were performed to determine diet composition. All gobies feed primarily on benthic invertebrates and have a similar prey spectrum; species specific and individual differences were found for Coryphopterus species, whereas Gnatholepis thompsoni had an unspecialised diet. An overlap in diet and dentition as seen in Coryphopterus spp. suggests that they use distinct microhabitats and do not compete for food. Observations on their feeding behaviour indicate that differences exist between size and sex within species of Coryphopterus and external factors such as currents, wave action and suspended particles in the water column play a major role.