First record of clasper malformation of Pseudobatos buthi (Chondrichthyes: Rhinobatidae) in the Gulf of California

Elasmobranchs in the Gulf of California have been found with malformations, probably originated during embryonic development or caused by environmental anomalies and pollution associated with intense mining activity in the region. Clasper malformations are reported for the first time in two specimens of Pseudobatos buthi, a species recently described from the Gulf of California. The function of the claspers was not affected by the size difference, because specimens presented the distinctive characteristics of an adult individual. The reproductive system did not show any malformation, with symmetrical testes. Histological analysis of the testes revealed a normal spermatogenic development. To elucidate the causes and to detect a possible effect of the morphological malformations due to high levels of heavy metals, trace concentration values (cadmium, copper, iron, manganese, silver, lead and zinc) were determined in muscle and liver. Cadmium and lead concentrations in the muscle of the two specimens were below the permissible limit for human consumption (<0.05 mg kg-1); however, iron and zinc presented high values (0.455, 4.024 mg kg-1 in muscle and 21.931, 3.694 mg kg-1 in liver respectively). Mining activity and heavy metal pollution in the sampling area may have caused the malformations, which might be attributed to the high values of iron and zinc discovered in the muscle and liver.