A commercial fishing crew caught a dusky shark in mid-2011 off the coast of Baja California Sur, Mexico. When they cut the shark open, they discovered their catch had not only been pregnant, but had a fetus that was rather unique: The shark fetus was albino and only had one large eye centered in its face. Once the picture was shared on blog of Pisces Fleet Sportfishing, it quickly went viral around the internet, and many initially suspected the photo wasn’t real. However, scientists have confirmed that this cyclopean specimen is legitimate and the optical tissue was functional, though the animal likely wouldn’t have survived in the wild.
While the shark is somewhat reminiscent of Blinky, the three-eyed fish from The Simpsons, it is the result of the prosencephalon (forebrain) failing to separate into two hemispheres during embryonic development. As the brain failed to separate, only one optic lobe formed, leading to only one eye. This condition often results in miscarriage, and those that survive to birth typically die within a day. As the shark would have needed to defend itself from the moment it was born, it would not have lasted very long.
"This is extremely rare, as far as I know less than 50 examples of an abnormality like this have been recorded,” Felipe Galván-Magaña of the Mexican Institute of Sciences stated on the blog of Pisces Fleet. While inhibited genetic expression of the proteins needed to form the brain can cause cyclocephaly, there are also environmental factors that can inhibit protein production. However, Galvan does not believe the latter is the case for this shark. "The water in the Sea of Cortez is one of the cleanest in the world, so it is not likely that this is a factor.”
While the shark embryo has been made available to scientists who wish to study it, Pisces Fleet is keeping the preserved embryo. Galván-Magaña went on to co-author published a paper on this incredible shark in Marine Biodiversity Records in 2013.