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

  • Felipe Galván-Magaña (a1), Ofelia Escobar-Sánchez (a1) and Maribel Carrera-Fernández (a1)

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.

Corresponding author
Correspondence should be addressed to: F. Galván-Magaña, Centro Interdisciplinario de Ciencias Marinas, Avenida IPN s/n Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, CP 23096, Mexico email:
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Bigelow, H.B. and Schroeder, W.C. (1948) Sharks. In Tee-Van, J., Breder, C.M., Hildebrand, S.E., Parr, A.E. and Schroeder, W.C. (eds) Fishes of the western North Atlantic. Part 1. Lancelets, cyclostomes, sharks. New Haven: Sears Foundation for Marine Research, Yale University, pp. 59546.
Bonfil, R.S. (1989) An abnormal embryo of the reef shark Carcharhinus perezi (Poey) from Yucatan, Mexico. Northeast Gulf Science 10, 153155.
Bornatowski, H. and Abilhoa, V. (2009) Record of an anomalous embryo of Rhinobatos percellens (Elasmobranchii: Rhinobatidae) in the southern coast of Brazil. Marine Biodiversity Records 2, e36.
Carrera-Fernández, M., Galván-Magaña, F. and Ceballos-Vázquez, B.P. (2010) Reproductive biology of the blue shark Prionace glauca (Chondrichthyes: Carcharhinidae) off Baja California Sur, México. Aqua: International Journal of Ichthyology 16, 101110.
Casarini, L.M., Gomes, U.L. and Tomas, A.R.G. (1997) Would Santos harbor dredged material dumping be a reason of teratogeny on Raja agassizi? In Congresso Latino-Americano sobre Ciências do Mar Colacmar. Caderno de Resumos 7. Santos: SBEEL, pp. 152153.
Castro, J.I., Woodley, C.M. and Brudek, R.L. (1999) A preliminary evaluation of the status of shark species. Blue Shark (Prionace glauca). FAO Fisheries Technical Paper, 380, 5354.
Castro-Aguirre, J.L. and Torres-Villegas, J.R. (1979) Sobre un caso de bicefalia funcional en Rhinoptera stendachneri Evermann y Jenkins (Chondrichthyes, Elasmobranchii, Batoideo), capturado en la costa occidental de Baja California, México. Ciencias Marinas 6, 2741.
Compagno, L.J.V. (1984) Sharks of the world. An annotated and illustrated catalogue of shark species know to date. Part 2. Carcharhiniformes. FAO Fisheries Synopsis. Rome: Food and Agriculture Organization of the United Nations.
Escobar-Sánchez, O., Galván-Magaña, F., Downton-Hoffmann, C.A., Carrera-Fernández, M. and Alatorre-Ramírez, V.G. (2009) First record of a morphological abnormality in the longtail stingray Dasyatis longa (Myliobatiformes: Dasyatidae) in the Gulf of California, Mexico. Marine Biodiversity Records 2, e26.
Ferreira, L.A., Ferreira, T.G.A. and Amorim, A.F. (2002) Embryo anomaly of blue shark, Prionace glauca (Linnaeus, 1758) Carcharhinidae, Carcharhiniformes. In III Reunião da Sociedade Brasileira para Estudo em Elasmobrãnquios SBEEL. Caderno de Resumos. João Pessoa: SBEEL, pp. 3839.
Ferreira, L.A., Ferreira, T.G.A. and Oliveira, L.E. (2000) Ocorrência de Xifopagia em embrião de tubarão-azul, Prionace glauca (Linnaeus, 1758) (Carcharhinidae, Carcharhiniformes). In II Reunião da Sociedade Brasileira para Estudo em Elasmobrãnquios–SBEEL. Caderno de Resumos. Santos: SBEEL, p. 71.
Goto, M., Taninuchi, T., Kuga, N. and Iwata, M. (1981) Four dicephalous specimens of blue shark, Prionace glauca, from Japan. Japanese Journal of Ichthyology 28, 157165.
Grady, S.W. (1992) Morphological deformities in brown bullhead administered dietary b-naphthoflavone. Journal of Aquatic Animal Health 4, 716.
Gubanov, Y.E.P. and Grigor'yev, V.M. (1975) Observations on the distribution and biology of the blue shark, Prionace glauca, (Carcharhinidae) of the Indian Ocean. Journal of Ichthyology 15, 3743.
Heupel, M.R., Simpfendorfer, C.A. and Bennet, M.B. (1999) Skeletal deformities in elasmobranchs from Australian waters. Journal of Fish Biology 54, 11111115.
Lamilla, J.G., Pequeño, G.R. and Kong, II.U. (1995) Dasyatis brevis (Garman, 1880) segunda especie de Dasyatidae registrada para Chile (Chondrichthyes, Myliobatiformes). Estudios Oceanológicos 14, 2327.
Laughlin, L. and Urogetz, J. (1999) An observation of the blue shark parturition in the southern California Bight. California Fish and Game 85, 8384.
Mancini, P.L., Casas, A.L. and Amorim, A.F. (2006) Morphological abnormalities in a blue shark Prionace glauca (Chondrichthyes: Carcharhinidae) foetus from southern Brazil. Journal of Fish Biology 69, 18811884.
Nakano, H. (1994) Age, reproduction and migration of blue shark in the North Pacific Ocean. Bulletin of the National Research Institute of Far Seas Fisheries. Enyosuikenho 31, 141256.
Pratt, H.L. Jr (1979) Reproduction of the blue shark, Prionace glauca. Fishery Bulletin 77, 445470.
Rosa-Molinar, E. and Williams, C. (1983) Fetal mummification in the sandbar shark. Carcharhinus plumbeus. Journal of Wildlife Disease 19, 156158.
Sandoval-Castillo, J., Mariano-Meléndez, E. and Villavicencio-Garayzar, C.J. (2006) New records of albinism in two elasmobranchs: the tiger shark Galeocerdo cuvier and the giant electric ray Narcine entemedor. Cybium 30, 191192.
Sandoval-Castillo, J. and Villavicencio-Garayzar, C.J. (2008) Fetal mummification in silky shark (Carcharhinus falciformis) from the Gulf of California, Mexico. Brazilian Archives of Biology and Technology 51, 551554.
Stevens, J.D. (1976) First results of sharks' tagging in the north-east Atlantic, 1972–1975. Journal of the Marine Biological Association of the United Kingdom 56, 9291037.
Strasburg, D.W. (1958) Distribution, abundance and habits of pelagic sharks in the Central Pacific Ocean. Fishery Bulletin of the Wildlife Service 58, 335361.
Suda, A. (1953) Ecological study on the blue shark (Prionace glauca L.). South Seas Area Fisheries Research Laboratory Report 26, 111.
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Marine Biodiversity Records
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