A new species of duck leech from North America formerly confused with Theromyzon rude (Rhynchobdellida: Glossiphoniidae)

Abstract

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