Cyclops abyssorum is a large species having a long furca where the two branches diverge towards the end. Its occurrence indicate that it is an opportunist, which survive in conditions when competitors have trouble.
Cyclops abyssorum is a large species having a long furca where the two branches diverge towards the end. This criterion can be used to distinguish C. abyssorum from C. scutifer. Another criterion is the seta attached to the 1. basal segment in the 4. pair of legs which is much thinner in C. abyssorum than in C. scutifer. Thorax segments 4 and 5 are clearly pointed. C. abyssorum has a whitish grey colour with a slight yellow tinge which is more distinct on the furca. Many variants of C. abyssorum have been described by different authors.
Female: Length 1.2–2.6 mm
Male: Length unknown
Ecology and distribution
C. abyssorum is a plankton species found in 8 % of the surveyed lakes and is found in all parts of the country. It occurs with highest frequency respectively below 100 m a.s.l. (15 %) and above1000 m a.s.l. (14 %). It is recorded from all types of water bodies, but is scarcely found at pH<5.0 and is most common in neutral water bodies. Both low (<1.0 mS/m) and high levels of electrolytes (>10.0 mS/m) seem to favour the species.
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