Scientists have for the first time identified a small gelatinous blob in the deep sea as a new species, using only high-definition underwater cameras. The creature, officially known as Duobrachium sparksae, is a new species of ctenophore, or comb jelly. It was discovered in an underwater canyon north-west of Puerto Rico in April 2015 but has only now been described in a research paper. No physical specimens of the animal have been collected but the species was declared from video taken 3,900 metres below the surface in an expedition led by the US National Oceanic and Atmospheric Administration (Noaa). Noaa used a remotely controlled robotic vehicle called Deep Discoverer to take high-definition images that enabled a full analysis of the blobs. “It was a beautiful and unique organism,” said Mike Ford, a Noaa Fisheries scientist. “We collected high-definition video and described what we saw. We went through the historical knowledge of ctenophores and it seemed clear this was a new species and genus as well. We then worked to place it in the tree of life properly.” Comb jellies, like Duobrachium sparksae, can be just a few millimetres long but are carnivores that eat small arthropods and are able to propel themselves forward by beating rows of hairlike structures found on their surface. Although they look similar, they are not closely related to jellyfish. Three individuals of the new species were spotted by the diving robot, intriguing scientists with their unusual behaviour. The comb jelly has two long tentacles that appear to anchor it to the seabed and control its position, as it moves like a hot air balloon. More research will be required to learn the exact role the new comb jellies play in their environment, but for now the videos will be housed at the Smithsonian National Museum of Natural History in Washington DC in lieu of physical specimens. “Video identification can be controversial,” said Allen Collins, another Noaa scientist who worked on the expedition. “For example, some insect species descriptions have been done with low-quality imagery and some scientists have said they don’t think that’s a good way of doing things. But for this discovery, we didn’t get any pushback. It was a really good example of how to do it the right way with video.”