Marine worms with small sucker-like structures have been discovered at the bottom of the Indian Ocean.
These animals belong to the group known as “spaghetti worms.” Their amusing nickname comes from the many fine tentacles that extend from their heads. They spread them around themselves to collect tiny pieces of food deposited on the seafloor. The rest of their bodies are often hidden inside a tube.
Sample of "spaghetti worms."
Credit: CSIRO.
Australian researchers encountered them during expeditions carried out in 2021 and 2022 around seamounts near Christmas Island and the Cocos Islands. They collected more than 850 marine worms, which were later added to the collections of the Australian Museum.
Among the specimens, one discovery particularly surprised the team. Beneath the bodies of some worms, the scientists observed structures that resemble small suckers. They are unusual enough to have inspired the name of a new genus, Terebellosuctoria.
The researchers identified two species belonging to this genus. One of them, Terebellosuctoria jimii, was found on a seamount at a depth of more than 670 metres. Some individuals measure up to 7.5 centimetres, not counting their long tentacles.
What could these suckers be used for? Spaghetti worms usually live in tubes set into mud or sand. But on the slopes of seamounts, currents can carry away much of the sediment. The researchers believe these structures help the animals remain attached to their support.
This function is still a hypothesis, based on their anatomy and habitat. The scientists did not directly observe the suckers in action on the ocean floor.
To determine whether these worms belonged to species that were already known or not, the team examined their bodies under a microscope and analysed their DNA. The study describes seven new species of marine worms in total, including the two members of Terebellosuctoria.
And this work is far from finished. The expeditions brought back hundreds of specimens, many of which are still waiting to be studied. Seamounts could harbour many more unknown animals, adapted to environments that researchers rarely have the opportunity to explore.