Daphnia longispina

Daphnia longispina is a planktonic crustacean of the family Daphniidae, a cladoceran freshwater water flea.

D. longispina is similar in size and sometimes confused with the often sympatric D. pulex (a very common species), but much smaller than D.

[2] D. longispina is found in a wide range of standing freshwater bodies from small, ephemeral rock-pools to large lakes.

[3][4] Like all Daphnia species, D. longispina is a filter feeder, collecting particles of about 2 to 40 μm suspended in the water.

The same or other females can switch at any moment from asexual to sexual reproduction, but producing haploid eggs, which require fertilization by males.

Female Daphnia longispina carrying a resting egg (="ephippium"). The two dark, oval spots on the ephippium mark the places where the two resting eggs are located. The female was collected in a rock pool in South-Western Finland. The animal is about 2 mm long.