Abstract
Purpose: :
Teleots are a successful vertebrate group, forming more than half the species of vertebrates. We observed that predatory telosts have more retinal spinules that non-predatory ones. However, we have not data about the relationship between cone synaptic ribbon numbers and predatory behavior. The aim of this work is to relate the number of synaptic ribbons per cone pedicle with the trophic behavior of teleosts.
Methods: :
The study was performed on the following species of teleosts belonging to perciforme order: Dicentrarchus labrax and Dicentrarchus punctatus (Moronidae family), Symphodus tinca and Symphodus roissali (Labridae family) and Diplodus vulgaris, Sparus aurata and Pagellus acarne (Sparidae family). Light-adapted retinas were processed for transmission-electron-microscopy and the number of synaptic ribbons per cone pedicle measured. To determine the intensity of trophic behavior the density, length, and breadth of dental microwear were measured.
Results: :
The number of synaptic ribbons per cone pedicle was greater in Moronidae than in both Labridae and Sparidae. In addition, the number of synaptic ribbons per cone pedicle and the parameters for dental-microwear showed an inverse relationship. The mean values for dental micro-features for Labridae and Sparidae were almost twice as large as those for Moronidae.
Conclusions: :
The number of synaptic ribbons per cone pedicle correlates negatively with the parameters for dental-microwear. These data support the hypothesis that retinal and dental parameters are biomarkers of trophic adaptations in teleost fishes.
Keywords: plasticity • horizontal cells • photoreceptors