Stylotheristus paramutilus sp. nov. is described and illustrated from bottom sediments collected in shallow-water and deep-sea habitats from the Black Sea. New species is characterized by well-developed lip region; twelve setiform cephalic sensilla in female and sixteen – in male; cervical setae present; spicules 0.6–0.9 cloacal body diameters long and expanded proximally; gubernaculum plate-like slightly curved; conico-cylindrical tail of 4.5–5.8 anal body diameters (except for one male with it equal to 12.9 anal body diameters) with three terminal setae. The present study provides the first Stylotheristus species records in the Black Sea. S. paramutilus sp. nov. has a wide spatial and bathymetrical (2–250 m depths) distribution at the Crimea region and the Istanbul Strait's (Bosphorus) outlet area of the Black Sea. However, in future molecular analysis will be required to confirm the identity of these specimens from different Black Sea habitats.