Phallostethus cuulong, a strange species of fish recently discovered in Vietnam, is raising eyebrows for its extremely unique features. The fish is part of the larger Phallostethidae family which all are distinguished by their most unique feature which is that their penises are located on their heads according to NBC News.
But for Phallostethus cuulong the uniqueness doesn’t start with its penis on its head. It also has a retractable barbed hook beneath its chin so that when it starts mating with a female of the species it can hold her in place to make sure its sperm gets where it needs to go. Talk about “rough sex”, the Phallostethus cuulong ranks up there with the black widow, which bites the head off of male spiders the moment they climax.
Lynne Parenti, curator of fishes at the National Museum of Natural History in Washington, D.C, told National Geographic:
Head-to-head mating is apparently “a very efficient way to do it. There’s still a lot more to discover about Phallostethus, she added—P.cuulong is only third species found in its genus. It’s a lovely little fish with a very complex anatomy and I’m just delighted that we’re finding more of them.”
Phallostethus literally means “Penis Chin” in Greek and this is where scientists, who discovered the fish in Vietnam’s Mekong Delta, got the name from. The fish’s penis and hook are not the only odd organs located on the animals head, the anus is there
The hook may seem like a bit of evolutionary overkill, but it serves a vital purpose. Most fish fertilize eggs outside of the female’s body so it makes exact placement of the sperm kind of unnecessary. For the Phallostethus cuulong it needs to hold the female in place because it needs to precisely place the sperm inside of the female, and while underwater this is not always the easiest thing to do.
Researchers at Can Tho University in Vietnam, led by zoologist Koichi Shibukawa of the Nagao Natural Environment Foundation in Tokyo, Japan collected nine specimens of the Penis Head Fish. They captured six males and three females
The news has been ripe with discoveries lately of other phallic shaped animals. The Penis snake, a type of worm that not only is shaped like a penis but because it has no eyes on its head eerily looks just like a penis too, was recently discovered in South America.
A detailed description of the Penis Head Fish will be appearing in the July edition of the journal Zootaxa.