Depth-Related Modifications in the Electroreceptive System of the Eurybathic Skate, Raja radiata (Chondrichthyes: Rajidae)

Abstract

The peripheral component of the electroreceptive system (the ampullae of Lorenzini) in the eurybathic skate, Raja radiata, is similar in general arrangement to that previously described in other species. The majority of the pores are located on the ventrum, with the mouth situated at the geometric center. The ampullae are restricted to four bilaterally located connective tissue capsules, and each exhibits an ontogenetically constant number of alveoli. The gross structure of individual ampullae shows considerable variation, with the number of alveoli and the overall ampulla size increasing with depth, particularly in those anatomical areas most closely associated with the feeding strike. It is suggested that these differences represent intraspecific modifications for enhanced electroreceptive sensitivity which correlate with bathymetric variation in the prey-depauperate deep-sea.