First record of a morphologically abnormal and highly metal-contaminated Spotback Skate Atlantoraja castelnaui (Rajiformes: Arhynchobatidae) from southeastern Rio de Janeiro, Brazil

Abstract

This paper reports the first record of a morphologically abnormal and highly metal-contaminated Spotback Skate Atlantoraja castelnaui (Ribeiro, 1907) (Elasmobranchii, Rajidae) in Rio de Janeiro, Brazil. Incomplete fusion of the right pectoral fin with the head was observed, while a radiography indicated muscle sheaf discontinuity near the rostrum. Extremely high contamination by several elements, including teratogenic As, Hg and Cd in the individual was detected. The observed morphological deformity may be due to high concentrations of teratogenic elements in the environment, possibly playing a role in abnormal embryonic development in egg cases exposed to high environmental concentrations of these contaminants. Atlantoraja castelnaui is the least biologically understood member of the genus Atlantoraja, and this paper furthers both morphological observations and ecotoxicological assessments on this species.