A bizarre sea beast has one head yet hundreds of anuses, scientists have revealed, after studying its biology in detail.
The Ramisyllis multicaudata, a marine worm, lives within sponges off the Australian coast and has a branching body allowing its head to give way to multiple different bodies.
It was discovered near Darwin, Australia in 2006 and formally described in 2012.
Now a detailed study of its biology has been completed, revealing that when its body divides, its organs do too.
This means its branching digestive tract leads to hundreds of different anuses.
Dr Maite Aguado from the University of Göttingen, who co-authored the study in the Journal of Morphology, said the worm could develop more than 1,000 branches.
(Image: Credit: Ponz-Segrelles et al. 2021. J.Morphol. via Pen News)
She said: “The animal is a marine worm, but instead of having a body like a tube or a cylinder with an anterior part and a posterior end, it has one head, but multiple posterior branches.
“That’s why it is called ‘the tree syllid-worm’ or ‘the animal that looks like a tree’.
“We were able to count more than 500 branches in one specimen, but we think that they can easily reach 1000.
“This animal has one mouth, one head, but hundreds of anuses!”
The head of the worm is found inside the sponge, where it is safer, according to Dr Aguado.
(Image: Credit: Ponz-Segrelles et al. 2021. J.Morphol. via Pen News)
The body branches fan out through the internal canals of the sponge, before emerging at the external pores and exploring the surface.
Dr Maite Aguado added: “We think that this body is perfectly adapted to live within sponges.
“If the worm lived outside, having one head but multiple branches would be fatal for moving and escaping predators, for instance.
“However, living inside the sponge, the animal is protected, explores the canals and easily moves inside.”
The scientist’s team also uncovered the secrets of how the creature reproduces.
She said: “The posterior segments get full of gametes (sperm or ovules), they develop swimming paddles, and a new ‘head’ with eyes and nervous ganglia arises.
“When this ‘stolon’ is ready, it detaches from the anterior end and swims to find other stolons of the opposite sex.
“What makes this animal special is that – since it has thousands of posterior ends – it is able to produce thousands of stolons.”
But several questions remain unanswered about the creature including how long it lives for.
“There is still a long way to go to fully understand how these fascinating animals live in the wild,” said Dr Aguado.
“For example, this study has concluded that the intestines of these animals could be functional, yet no trace of food has ever been seen inside them.
“So it is still a mystery how they can feed their huge branched bodies.
“Other questions raised in this study are how blood circulation and nerve impulses are affected by the branches of the body.”