A confusing trio of Branchinecta (Crustacea: Anostraca) from the western North America with a description of a new species

Confusion exists in the literature of the 1990s among three western North American species: Branchinecta coloradensis, B. dissimilis, and a new species described here as Branchinecta oriena n. sp. This confusion resulted from the very similar appearance of the basal segments of the male's second antennae of these three species, and that the description of B. dissimilis did not illustrate or make clear in the description the unique shape of the distal segments of the second antenna. As to confusion with B. coloradensis, some males of B. coloradensis fail to produce an apophysis at the proximal end of the basal segment of the males' second antennae. In many young, but reproductive males of B. coloradensis in California, the apophyses are almost imperceptibly developed and thus easily overlooked. B. oriena n. sp. are separated from all other Branchinecta by the form of the male second antennae, the dorsolateral ornamentation of the female, and the form of the (cyst) resting egg.