In a scene straight out of a horror movie, biologists discovered an embryo of a two-headed shark that was growing in their lab. This is the first time that such abnormalities have been observed in an egg-laying shark, said the researchers.
The find was made by biologists at the University of Malaga, Spain where the researchers were sifting through hundreds of Atlantic sawtail catshark embryo. The collected samples are to be used in a study regarding how the shark's cardiovascular system develops when they noticed the creature growing inside a translucent egg.
Two-Headed Conjoined Twins Exceptionally Rare Among Any Shark Species
They described the abnormal shark as having two heads, each with a mouth; two eyes, a brain, a notochord, and five gill openings on each side. The body, on the other hand, contained two hearts, two esophagi, two stomachs, and two livers. The creature shared one intestine, one set of kidneys, and reproductive organs reported the Daily Star.
While this is the first findings on shark species that lay eggs, scientists have observed similar anomalies to those that deliver live offspring. However, those cases are notoriously rare with only seven other two-headed shark specimen appearing in scientific literature.
Two-Headed Conjoined Shark Has A Low Survival Rate
Unfortunately, the world will never know if this particular specimen can survive in the wild having been born the way it was. Researchers have already euthanized and preserved their discovery in alcohol and formaldehyde through the course of their study.
"Survival after birth may occur, but would likely be very brief," explained Michelle Heupel, a researcher at the Australian Institute of Marine Science. "It is unclear whether the two heads will preclude swimming and prey capture, and whether joined internal organs will function adequately."
Heupel went on to say that this abnormality is exceptionally rare and therefore does not pose a threat regarding the conversation of this particular shark species. Indeed, two-headed conjoined twins are also scarcely observed among other species with a vertebrate, including humans, according to Vox.
As of now, biologists don't have an explanation on why shark fetuses fuse. They also didn't find any teratogenic - birth defect-causing - agent in their incubation tanks.
