Marine Biodiversity Records

Research Article

Embryonic bicephaly in the blue shark, Prionace glauca, from the Mexican Pacific Ocean

Felipe Galván-Magañaa1 c1, Ofelia Escobar-Sáncheza1 and Maribel Carrera-Fernándeza1

a1 Centro Interdisciplinario de Ciencias Marinas, Avenida IPN s/n Col. Playa Palo de Santa Rita, La Paz, BCS, CP 23096, Mexico


A case of bicephaly in embryos of the blue shark Prionace glauca in the Mexican Pacific Ocean is described. Malformed female shark embryos were found in pregnant females caught in the Gulf of California (Punta Arenas) and off the western coast of Baja California Sur, Mexico (San Lázaro). Abnormal sharks showed a symmetric bicephaly that could be caused by the high number of embryos found in the uterus of the blue shark, which is the most fecund species of shark in the world. The abnormality probably began during the embryonic development.

(Received May 16 2010)

(Accepted October 29 2010)

(Online publication January 14 2011)