Marine biologists have described a third species of branching syllid worm — and the second within the genus Ramisyllis — living inside an undescribed species of the sponge genus Petrosia found in shallow waters at Sado Island, Japan. Ramisyllis kingghidorahi. Image credit: M.T. Aguado. Among over 20,000 species of annelids (ringed or segmented worms), only two branching species with a highly modified body-pattern were known until now:...
