Arctodiaptomus laticeps is widely distributed in the central parts of Norway, and is not found in the two northernmost counties and in the south. It is categorized as moderate acid sensitive.

Key characteristics

The lateral expansion of the last thorax segment in Arctodiaptomus laticeps is comparatively small and scarcely at all extant, and the species may therefore resemble Eudiaptomus graciloides. It is separated from that species by the length of the antennae which reach the base of the first abdominal segment in A. laticeps, while they reach far beyond the furca in E. graciloides. The genital segment is slightly expanded anteriorly. Its furca is more than twice as long as wide, comparatively longer than in its relative A. bacillifer. The colour of A. laticeps is generally bluish.

Female: Length 1.2–1.9 mm

Male: Length 1.1–1.4 mm

Ecology and distribution

A. laticeps is widely distributed in the central parts of Norway, and is not found in the two northernmost counties and in the south. It is found between 7 and 1554 m a.s.l. with its highest frequency above 300 m a.s.l., where it mainly inhabits lakes with surface area >1 da. A. laticeps is categorized as moderate acid sensitive, and only occasionally recorded when pH<6.0. It is found in electrolyte poor as well as in relatively electrolyte rich water.

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