Bosmina longispina
With its characteristic look Bosmina longispina is the most common cladoceran in Norway. In number, it may dominate both in the pelagial as well as in the littoral. The frequency decrease slightly above 1000 m a.s.l., and it occurs with lower frequency in ditches and small ponds.
Key characteristics
Bosmina longispina (female)
Bosmina longispina (male)
Seen from the side this species has an almost circular shape, being short and wide. Its head is evenly rounded anteriorly, and ventrally it ends in a fairly long ventrally directed rostrum (1. antennae). B. longispina can be distinguished from B. longirostris by the way the rostrum is tapered to the rest of the body, being more continuous in B. longirostris than in B. longispina. While the dorsal edge of the carapace is strongly arched, the ventral edge has an almost imperceptible incurvature midway, posteriorly ending in a pointed process (mucro). The abdominal claw has 6–7 teeth decreasing in size towards the end. The species is more or less colourless, but littoral specimen may have a brown tinge.
Female: Length 0.4–1.2 mm
Male: Length 0.4–0.7 mm
Ecology and distribution
B. longispina is the most common cladoceran in Norway, both in the zooplankton and in the littoral zone. It occurs in more than 80 % of all water bodies. The frequency decrease slightly above 1000 m a.s.l., though it is found as high as 1501 m a.s.l. It is the dominating species in water bodies of all sizes, but it occurs with lower frequency (40 %) in ditches and small ponds (<0.01 ha) than in lakes. Due to pH and conductivity B. longispina is more common in acid, electrolyte poor water than in alcalic, electrolyte rich water.
| Vitenskapelig navn | < 1,0 | 1,0 - 1,4 | 1,5 - 1,9 | 2,0 - 2,9 | 3,0 - 3,9 | 4,0 - 4,9 | 5,0 - 6,9 | 7,0 - 9,9 | > 10,0 |
|---|---|---|---|---|---|---|---|---|---|
| 92,8 | 91,6 | 81,7 | 95 | 96,7 | 95,8 | 94,4 | 79,7 | 68,9 |
| Vitenskapelig navn | < 0,01 | 0,01 - 0,09 | 0,1 - 0,9 | 1,0 - 9,9 | 10,0 - 99 | 100 - 999 | > 1000 |
|---|---|---|---|---|---|---|---|
| 0 | 63,3 | 80,9 | 88,6 | 92 | 94,1 | 92,2 |
| Vitenskapelig navn | < 100 | 100-299 | 300-499 | 500-699 | 700-999 | >1000 |
|---|---|---|---|---|---|---|
| 88,1 | 89 | 92,7 | 90,9 | 93,9 | 81,8 |
| Vitenskapelig navn | < 4,5 | 4,5 - 4,9 | 5,0 - 5,4 | 5,5 - 5,9 | 6,0 - 6,4 | 6,5 - 7,0 | 7,0 - 7,4 | > 7,5 |
|---|---|---|---|---|---|---|---|---|
| 90,6 | 96,8 | 93,3 | 89,5 | 90,8 | 85,5 | 89,2 | 79,8 |
Look-alikes
Bosmina coregoni and B. longirostris
