Eucyclops serrulatus, with a furca which is about 4–6 times as long as wide, is the most common copepod in Norway. It is a very tolerant species and is one of the first to colonize new established waterbodies.

Key characteristics

Eucyclops serrulatus has a body which is moderately slender and with a furca which is about 4–6 times as long as wide. Populations sampled in early spring or late autumn may have a furca that is somewhat longer. The outer margins of each branch have a dense row of small teeth. The last joint of the antennae has a smooth surface. The colour is more or less dark olivaceous with a greenish tinge.

Female: Length 0.8–1.5 mm

Male: Length 0.6–0.8 mm

Ecology and distribution

E. serrulatus is the most common littoral copepod in Norway and occurs in 43 % of the water bodies. It is distributed in all parts of Norway, from sea level and up to 1486 m a.s.l. It occurs with its highest frequency in localities below 300 and above 1000 m a.s.l. and is common in micro- and macrophyte vegetation in both small pools and in the littoral zone of big lakes. The species has a wide tolerance towards pH and found in lakes having pH varying between 4.0 and 9.9. It is also tolerant towards electrolytes and found in brackish water (0.4–957 mS/m).

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