What is the longest animal in the world? It is a siphonophore, a relative of jellyfish and corals. This was discovered by a research team two years ago during its more than month-long exploration of underwater canyons off the coast of Ningaloo Coast, a protected area off the coast of Western Australia famous for hosting the continent's largest barrier reef.
Siphonophores are peculiar organisms. Seen from the outside they look like single individuals, but they are actually colonial organisms, composed of elements called zooids, that is, multicellular entities each of which specializes in a task that serves contributes to the functioning of the entire colony.
Underwater explorers encountered one in April 2020 belonging to an as-yet-undescribed species of the genus Apolemia, an animal that resembles a very long rolled ribbon and whose observed specimen reached a length of 45 meters.
At 45 metres, it may even be the longest animal ever measured. To date, specialists are working to obtain a more accurate estimate of the size of the siphonophore.