A new species of Stilbonematinae (marine free-living nematodes with ectosymbiotic bacteria), Catanema schiemeri n. sp. is described from subtidal sand in the Northern
Adriatic near Rovinj, Croatia. In addition to the obligate coat of ectosymbiotic Gammaproteobacteria large stalked sulfur bacteria are found attached to the anterior body
region of about 25% of the individuals. The new species is distinguished from its congeners by its size and a series of precloacal supplements in males.