Reassignment of Anaperus trifurcatus Beltagi, 1983 to the genus Amphiscolops

Anaperus trifurcatus was described by Beltagi (1983), who collected the worm from brown algae taken from the upper intertidal zone in the Red Sea. This species was placed in the genus Anaperus despite lacking the stimulatory organs (adenodactyls) that are diagnostic for the family (Dörjes 1968). A. trifurcatus has a trilobed posterior end, zooxanthellae, frontal glands, a statocyst, eight bursal nozzles, and a single male gonopore and is better suited for placement in the genus Amphiscolops Graff, 1904 (see discussion in Winsor 1990). While one other known species of Amphiscolops, A. bermudensis Hyman, 1939, also has a trilobed posterior end, A. trifurcatus is apparently unique in lacking eyes and a female gonopore, and in its possession of ciliated “sensory” pits on both sides of the male gonopore. We hereby transfer this species to the genus Amphiscolops .