Redescription of Diacyclops nearcticus (Kiefer, 1934) and description of four similar new congeners from North America, with comments on D. crassicaudis (G. O. Sars, 1863) and D. crassicaudis var. brachycercus (Kiefer, 1927) (Crustacea: Copepoda)

Abstract

Diacyclops nearcticus is redescribed from the type specimen, collected in Massachusetts, U.S.A. Four similar new congeners, some previously mistaken for D. nearcticus, are described from the U.S.A. and Canada. Diacyclops harryi n.sp. occurred in seeps, wells, an acid bog, a pitcher plant, and stream hyporheic zones in the District of Columbia, Maryland, New York, North Carolina, Pennsylvania, and Virginia. Diacyclops chrisae n.sp. was collected from the groundwater of Wye Island, Maryland, with a probable record from the hyporheic zone of a stream in Ontario. Diacyclops sororum n.sp. occurred in drift in streams in Virginia and Texas. Diacyclops alabamensis n.sp. was collected from a well in Alabama. A previous record of D. nearcticus from Missouri could not be confirmed. Some morphological details of the probable type specimens of D. crassicaudis var. brachycercus and of a specimen of D. crassicaudis s.str. from Saskatchewan are presented. North American records of D. crassicaudis s.str. and D. crassicaudis var. brachycercus are reviewed.