Complex and flexible life history of a freshwater benthic harpacticoid species

SUMMARY. 1. The life history of the benthic harpacticoid paracamptus schmeili (Crustacea: Copepoda) in the oligotrophic lake Pääjärvi, South Finland, was described from quantitative field data of all developmental stages. The generation time of P. schmeili was exceptionally long for a meiobenthic animal and varied with depth from 1 year in the littoral (depths of 1 and 2m) to 2 years in the upper profundal (13 and 14 m). and to 3 years in the lower profundal (40 m).
2. In the littoral, egg-bearing females were found from April to October, with peaks in spring and late summer, while in the profundal a single summer egg peak was present.
3. In the littoral and in the lower profundal there were three, in the upper profundal) probably four, simultaneous parallel cohorts over-wintering as adults, medium-sized (at 13 m also large) copepodids and medium-sized nauplii. Reproductive isolation of the parallel cohorts was possible at all depths.
4. The between-depth variation in the life history of P. schmeili was probably mainly a phenotypic response to the changing level and seasonal course of temperature and food supply. Growth and reproduction were confined to summer months, and the lengthening generation times with depth accompanied decreasing summer temperatures.
5. The cessation of growth in winter was probably due to a shortage of food, which may also have accentuated the size differences of the overwintering groups through intraspecific competition.     

Glaciella,a new genus of freshwater Canthocamptidae (Copepoda,Harpacticoida) from a glacier in Nepal,Himalayas

A new genus and new species of Canthocamptidae: Glaciella yalensis (Copepoda: Harpacticoida) from the surface of Yale Glacier, Nepal is described. This new species was collected from cryconite-pit on the surface of the glacier and is closely related to genus Maraenobiotus, but easily distinguishable from its species in the following: 1) segments and setae on endopodites of legs 2–4 in the male differing shape, 2) exopodites of male legs 3–4 with modified setae, 3) caudal seta in female absent. Body color of this copepod is red in live specimens.Contributions No. 86 Itako Hydrobiological Station, Ibaraki University.