Abnormalities in two shark species, the blue shark, Prionace glauca, and the school shark, Galeorhinus galeus (Elasmobranchii: Carcharhiniformes), from the Canary Islands, Eastern tropical Atlantic.

Abstract

A total of six abnormal embryos of shark species, five blue shark, Prionace glauca (Linnaeus, 1758), and one school shark, Galeorhinus galeus (Linnaeus, 1758), are herewith reported from the Canary Islands (eastern central Atlantic). Two P. glauca embryos showed two totally separated heads on one trunk (bicephalism), while the other three embryos had a single head with some duplicated parts, such as the mouth or the eyes (diprosopia). Galeorhinus galeus embryo showed cephalic abnormalities. Possible causes of these abnormalities are briefly discussed.