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This study presents the second worldwide report on abnormal embryos of the sharpnose sharks, Rhizoprionodon, based on the two species (Rhizoprionodon porosus and Rhizoprionodon lalandii) occurring on the Brazilian coast. For R. porosus two conjoined twin embryos showing complete duplication of the vertebral column, viscera and several external structures (head, first and second dorsal fins, pectoral fins), and scoliosis in both axis at the pelvic fin level are reported. The three embryos of R. lalandii exhibited numerous lordosis and kyphosis along the entire vertebral column. The possible relationship between anomalies and the human major threats to sharks is discussed based on previous reproductive, genetic and ecotoxicological studies on R. lalandii for southern Brazil. [ABSTRACT FROM PUBLISHER]

Occurrence of abnormal rays reported in Indian waters was stumbled upon in the late 19th Century, but it was revised in the early 20th Century and in the past two decades. Reported morphological abnormalities for elasmobranchs in the Indian waters are restricted to pectorals that fail to unite with the sides of the head and fins that developed thick muscular segments. The occurrence of the malformed or adapted specimen Gymnura poecilura suggested reasons for adaptations or malformations. [ABSTRACT FROM AUTHOR]