C. Key to Species in the Genus Moina
This identification key for morphological forms is derived from species descriptions in Goulden, who reported six species from N.A. Moina and Moinodaphnia are typically planktonic, but the majority of species are restricted to small
temporary ponds, saline, or alkaline lakes. The habitat is often ephemeral, turbid, and warm. Adult females reach 1–2mm, with one Moina species that is only about 0.5mm long.
1a. A simple distal tooth (next to the claw) in the row of teeth along the dorsal margin of the postabdomen; western N.A. saline lakes
… Moina hutchinsoni
1b. A double (bifid) distal tooth (next to the claw) in the row of teeth along the dorsal margin of the postabdomen …2
2a (1b). A row of teeth along the side of the setae on the last and penultimate segments of the first thoracic leg; ephippium with two eggs; north
temperate, coast to coast … Moina Macrocopa
2b. Feathery setules along the side of the setae on the last and penultimate segments of the first thoracic leg; ephippium with one or two
eggs …3
3a (2b) Long hairs on head and carapace …4
3b. Hairs completely absent from head and carapace …5
4a (3a). Never over 1.2mm long, one egg per ephippium; an uncommon species found from midwestern and southeastern United States and west into Mexico … Moina affinis
4b. Some adults longer than 1.2mm; two eggs per ephippium; southwestern United States to Argentina … Moina wierzejski
5a (3b). Length less than 1.2mm, one egg per ephippium; temporary ponds to large lakes in the north temperate zone, coast to coast and south to
Paraguay; from temporary ponds to large lakes … Moina micrura
5b. Some adults longer than 1.2mm; two eggs per ephippium; one population known from southern California …Moina brachycephala
Reference: Ecology and Classification of North American Freshwater Invertebrates (Third Edition)
2010
Stanley L. Dodson, Carla E.Cáceres,D. Christopher Rogers
Chapter 20 - Cladocera and Other Branchiopoda
https://doi.org/10.1016/B978-0-12-374855-3.00020-0