Perinereis kaustiana sp. nov. All pictures are from the holotype (NTNU-VM-86011) if not stated otherwise A anterior end, prostomium, dorsal view B anterior end, prostomium, ventral view C jaws and respective jaw canals (JC), dorsal view D pharynx, maxillary ring (Areas III and IV), ventral view; black arrows, lateral patches with two paragnaths each E pharynx, oral ring (Areas VI), dorsal view F pharynx, maxillary ring (Areas I and II), dorsal view G pharynx, oral ring (Areas VII–VIII), ventral view; black arrows, furrow regions; white arrows, ridge regions H posterior end; white arrows, pygidial Tentacular cirri, paratype (NTNU-VM-86015) I anterior body, tentacular cirri reaching chaetiger 9, paratype (NTNU-VM-86015) J worm’s eyes, right side, paratype (NTNU-VM-86015). Abbreviations: chaet., chaetiger; Pyg., Pygidium. Scale bars: 500 μm (A, B, I); 250 μm (E, F, H); 100 μm (D, G); 125 μm (J); 75 μm (C).