First record of a pectoral-fin abnormality in the broadnose skate Bathyraja brachyurops (Elasmobranchii, Arhynchobatidae)

The first case of a morphological abnormality in the broadnose skate Bathyraja brachyurops is reported. The specimen was captured by a vessel fishing in the Southwest Atlantic Ocean off the coast of Argentina. Radiographs and mammographs were used to visualize the abnormality in greater detail. The specimen exhibited a lack of union between both pectoral fins and the head region. Ventral photographs revealed that the propterygia does not articulate with the antorbital cartilage or there is a malformation in the antorbital cartilage. It could cause the pectoral fins to be incomplete. The rest of the body seemed to have developed normally, with the rostrum, the other fins, and the caudal area showing no abnormalities. Even though it is difficult to assess the causes of the abnormalities, it is believed that they may be due to environmental factors, such as heavy metal pollution. The pectoral-fin deformity could interfere with locomotion, feeding, or mating, affecting intraspecific competition.