The 22-inch-long (56-centimeter-long) fetus has a single, functioning eye at the front of its headthe hallmark of a congenital condition called cyclopia, which occurs in several animal species, including humans.
Earlier this year fisher Enrique Lucero León legally caught a pregnant dusky shark near Cerralvo Island (see map) in the Gulf of California. When León cut open his catch, he found the odd-looking male embryo along with its nine normal siblings. "He said, That's incrediblewow," said biologist Felipe Galván-Magaña, of the Interdisciplinary Center of Marine Sciences in La Paz, Mexico.
Once Galván-Magaña and colleague Marcela Bejarano-Álvarez heard about the discoverywhich was put on Facebookthe team got León's permission to borrow the shark for research. The scientists then x-rayed the fetus and reviewed previous research on cyclopia in other species to confirm that the find is indeed a cyclops shark.
Cyclops sharks have been documented by scientists a few times before, also as embryos, said Jim Gelsleichter, a shark biologist at the University of North Florida in Jacksonville. The fact that none have been caught outside the womb suggests cyclops sharks don't survive long in the wild.
http://news.nationalgeographic.com/news/2011/10/pictures/111013-shark-albino-one-eyed-fetus/