A NEW SPECIES OF DUCK LEECH FROM NORTH-AMERICA FORMERLY CONFUSED WITHTHEROMYZON-RUDE (RHYNCHOBDELLIDA, GLOSSIPHONIIDAE)

In North America, Theromyzon specimens with three annuli between the m ale and female gonopores belong to the newly described species Theromy zon trizonare. A detailed description of the new species is provided, with a description of the external and internal features that differen tiate it from other species in this genus. The diagnostic features of T. trizonare include the presence of three annuli between the gonopore s, two female pores opening to the exterior, and atrial cornua at the terminal ends of the paired male ducts.