The scientists found a shark embryo with two heads. Although such a find is rare, there are reports that such oddities are becoming more common. The shark embryo is of an Atlantic Sawtail Catshark (Galeus atlanticus.) The researchers had been investigating a series of shark embryos for biological research. Of 797 samples, the shark embryo with two heads, unsurprisingly, stood out from the other research samples.
Upon further investigation, National Geographic reports, the shark was found to have two hearts, two stomachs, two esophagi, and two livers, in addition to the two heads. Although these various biological constructs were observed, the shark had just one body.
Rare observations of two headed sharks have been reported before but never with the Atlantic Sawtail Catshark species. The Atlantic Sawtail Catshark is a little-known species of catshark. The shark is slender and firm-bodied, it has a slightly flattened head with a moderately long, flattened snout.
Sharks are divided into viviparous and ovoviviparous species. By viviparous this means the species develops inside the mother’s body without eggs; whereas with an ovoviviparous species, this means the species is hatched inside the mother’s body from eggs. This discovery is the first recorded example of an oviparous species.
The cause is most likely a genetic mutation, and of a type that can also occur with snakes and lizards. According to Laboratory Roots, over-fishing can lead to a condition called dicephaly, which is the product of inbreeding and this triggers genetic mutations to occur.
The findings have been published in the Journal of Fish Biology, in a research paper headed “Dicephalous v. diprosopus sharks: record of a two-headed embryo of Galeus atlanticus and review of the literature.”
