title: [Morphology and age variation of Daphnia galeata Sars (Cladocera: Daphniidae) in two adjacent water bodies of the Kola Peninsula].
abstract: The morphology and age variation of Daphnia galeata Sars (Cladocera: Daphniidae) in two adjacent water bodies of the Kola Peninsula are studied. The reliability of characters usually used for diagnosis of adult individuals of the given species was verified, and their formation in the postembryonic period was traced. If the identification of D. galeata from Lake Bolshoi Vudvyar caused no doubts, the population from Lake Malyi Vudvyar was atypical with respect to several morphological characters. We concluded that plastic characters, such as body shape, as well as the shape of the dorsal keel and helmet on the head are unreliable for distinguishing closely related species of water fleas. At the same time, some small-size characters, for instance, the relative depth of the medial crest on the posterior side of the head, allow us to diagnose this species with confidence.
authors.forename: A G
authors.initials: AG
authors.lastname: Kirdiashcheva
authors.forename: A A
authors.initials: AA
authors.lastname: Kotov
mesh_terms: D000818:Animals; D003621:Daphnia / Q000033:anatomy & histology* / Q000166:cytology; D005260:Female; D060106:Lakes; D008297:Male; D013045:Species Specificity