A new species of flatworm that fences with its penis has just been discovered in the waters of Botany Bay.

The Imogine lateotentare is a member of a group of predators commonly known as oyster leeches.

Emma Johnston and her colleagues, Ka-Man Lee and Michel Beal at the University of NSW, said that although they were one of the simplest organisms known, their behaviour was quite complex.

“They squirm around these communities [of creatures which live on hard surfaces and cannot move] and attack the barnacles. They squirt digestive juices into them and suck their flesh out.”

Less than two centimetres long the new flatworms are hermaphrodites, meaning they have both male and female parts. To reproduce they try to stab each other with their genitals (check the video.) The first to penetrate inserts sperm and then goes on to spar with another flatworm, while the “loser” lays and broods the eggs.

Despite this rather cruel love making, the flatworms are also the simplest animals in the world showing parental care.

“They sit over the top of the eggs, aerate and protect them from predators. For a species so low on the evolutionary tree that’s very sophisticated behaviour.”

Via Collision Detection Sydney Morning Herald.