Eudiaptomus gracilis
Eudiaptomus gracilis is the most common species among diaptomids and is distributed in the south and the north eastern part of Norway. With a few exceptions, it is found below timberline in acid as well as in alkali water.
Key characteristics
Eudiaptomus gracilis (female)
Eudiaptomus gracilis is very slender and the lateral expansion of the last thorax segment forms an outer angle which is somewhat more prominent in E. gracilis than in A. denticornis. Its furca is short, about twice as long as wide, while the anterior antennas are long and slender extending far beyond the furca (in some cases as much as the 4 or 5 outer joints). E. gracilis is generally very pellucid and almost colourless, but in some cases with a broad transverse band of a chocolate hue across the anterior division.
Female: Length 1.0–2.0 mm
Male: Length 1.0–1.5 mm
Ecology and distribution
E. gracilis is distributed in the south/southwest and northeastern part of Norway. It is the most common species among Diaptomids and occurs in about 30 % of the lakes. It is found with highest frequency in lakes >1 ha which are situated below 300 m a.s.l. However it is common also at higher elevations but above 1000 m a.s.l. it has been found only a few times. It is acid tolerant as well, as it is found in alkali water (pH>7.5). The contents of electrolytes seems to mean less for its distribution.
| 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 |
|---|---|---|---|---|---|---|---|---|
| 18,9 | 62,3 | 38 | 41,2 | 28,3 | 17,6 | 11,2 | 19,1 |
| 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 |
|---|---|---|---|---|---|---|---|---|---|
| 7,6 | 30,4 | 24,4 | 29,7 | 30 | 33,9 | 30,2 | 15,2 | 27,3 |
| Vitenskapelig navn | < 0,01 | 0,01 - 0,09 | 0,1 - 0,9 | 1,0 - 9,9 | 10,0 - 99 | 100 - 999 | > 1000 |
|---|---|---|---|---|---|---|---|
| 0 | 8,2 | 18,1 | 29,2 | 31,3 | 32,6 | 27,2 |
| Vitenskapelig navn | < 100 | 100-299 | 300-499 | 500-699 | 700-999 | >1000 |
|---|---|---|---|---|---|---|
| 31,5 | 45,9 | 20,6 | 23,4 | 20,4 | 1 |
Look alikes
Acanthodiaptomus denticornis and Eudiaptomus graciloides.
