Senecella calanoides

Senecella is the largest of the calanoids in Lake Champlain, with mature female prosome length often exceeding 2 mm. In addition to their large size, all stages have four setae, which is unique in the Lake Champlain community.

Males and females have slightly different urosome dimensions (esp. in the first segment, which is wider in females than males), but another identifying feature is the large fifth swimming leg males possess, which is clear when the individual is viewed in side profile.