Diaptomus is a genus of copepods with a single eye spot.

It is superficially similar in size and appearance to Cyclops.

However it has characteristically very long first antennae that exceed the body length.

It is a copepod of larger freshwater ponds, lakes and still waters.

[1] One species, the German endemic D. rostripes, is included on the IUCN Red List as a Data Deficient species.