An international team of zoologists and parasitic worm experts has identified a strange sea creature captured by an underwater photographer off the coast of Okinawa in 2018. As part of their project, reported in the open-access journal Current Biology, the group obtained and examined a sample of the marine creature.

Shortly after photographer Re Minezu took photos of the creature, he posted them online asking if anyone knew what it was. None of his followers had ever seen anything like it before. Intrigued, Minezu returned to the place where he had seen the creature and found it, or something similar. He captured the ladybug-sized creature and hid it until it attracted the attention of a research team. Minezu sent them a sample and waited for the results of the investigation.

The research team discovered that these were actually two creatures clinging tightly to each other. Both were species of cercariae, the larvae of parasitic worms. Researchers called one species “sailor” and the other “voyager” because of the roles they play when attached to each other.

The passengers were much smaller than the sailors and held each other tightly, forming a flat-topped hemisphere. Pointing their heads into the sphere, they pressed together, leaving their tails open, forming the outside of the hemisphere. The sailors grabbed the passengers by their tails and dragged their bodies into the water, resembling extensions of a sphere.

Further research on the group of two creatures revealed that the sailors used their bodies as appendages, flapping them like cilia on paramecia. Like ciliates, sailors moved their bodies in unison to move the combined mass in the water.

The researchers found that this type of swimming was usually initiated by only one member of the group; His movements were copied by others until everyone waved their arms and began pushing the unit through the water. At the same time, the collectivized group was able to make sharp movements, jump from one point to another and move steadily. Researchers suggest that these two creatures form a colony organism that meets the needs of both groups.