DragonflyPix

Dusky Riverdamsel (Pseudagrion jedda)

The Dusky Riverdamsel (Pseudagrion jedda) is a damselfly species of the family Coenagrionidae, which contains 30 species in Australia.

The identification key to the family Coenagrionidae consists of 54 couplets, 12 of which are pertinent to Pseudagrion jedda. Click on the numbers on the right to display the corresponding couplets. Or click on the ALLin1 button to see all the relevant couplets together in a single, scrollable window.

#FamilySpeciesCouplet No.
 CoenagrionidaeDusky Riverdamsel
(Pseudagrion jedda)
  • Coenagrionidae: Key couplet 1 of 54

  • ○ Damselflies without this combination of characters
  • b ↑
  • Coenagrionidae: Key couplet 14 of 54

  • couplet drawing
  • ● Anal vein leaving wing margin well basal to the level of Ac in both wings, so there is a basal segment of anal vein about the same length as Ac
  • a ↑
  • Coenagrionidae: Key couplet 15 of 54

  • ○ Hindwing longer than 22 mm
  • a ↑
  • Coenagrionidae: Key couplet 16 of 54

  • ○ Abdominal segments 2-4 bronze-black above

    ⇒ genus: Pseudagrion
  • b ↑
  • Coenagrionidae: Key couplet 18 of 54

  • ○ Synthorax with extensive brown to yellow areas, sometimes pruinescent
  • b ↑
  • Coenagrionidae: Key couplet 20 of 54

  • ○ Face dull brown
    ○ Abdominal segments 8-9 pale bluish grey, pruinescent

    ⇒ species: Dusky Riverdamsel (Pseudagrion jedda)
  • a ↑
  • Coenagrionidae: Key couplet 23 of 54

  • couplet drawing
  • ● Abdominal segments 3-5 brownish black above except for narrow, pale band at extreme base
    ● Lateral margin of dark upper surface almost straight
  • a ↑
  • Coenagrionidae: Key couplet 24 of 54

  • ○ 16-19 postnodal crossveins

    ⇒ species: Dusky Riverdamsel (Pseudagrion jedda)
  • b ↑
  • Coenagrionidae: Key couplet 40 of 54

  • ○ No such markings on thorax or abdomen
  • b ↑
  • Coenagrionidae: Key couplet 41 of 54

  • ○ Synthorax with extensive brown or yellow areas, sometimes pruinescent

    ⇒ genus: Pseudagrion
  • a ↑
  • Coenagrionidae: Key couplet 43 of 54

  • couplet drawing
  • ● Ac of hindwing beyond alignment of basal antenodal crossvein

    ⇒ genus: Pseudagrion
  • b ↑
  • Coenagrionidae: Key couplet 49 of 54

  • couplet drawing
  • ● Ac of hindwing beyond alignment with basal antenodal crossvein

    ⇒ genus: Pseudagrion
  • b ↑
1  
  • Coenagrionidae: Key couplet 1 of 54

  • couplet drawing
  • ● Arculus in hindwing situated beyond distal antenodal crossvein by at least the length of subcostal part of antenodal
    ○ Very small damselflies, hindwing shorter than 14 mm

    ⇒ genus: Agriocnemis
a ↑
b ↓
  • ○ Damselflies without this combination of characters

2  
  • Coenagrionidae: Key couplet 14 of 54

  • couplet drawing
  • ● Anal vein leaving wing margin well basal to the level of Ac in both wings, so there is a basal segment of anal vein about the same length as Ac
a ↑
b ↓
  • couplet drawing
  • ● Anal vein leaving wing margin nearer to or beyond level of Ac
    ● Basal segment of hindwing anal vein, if present, not more than half length of Ac

3  
  • Coenagrionidae: Key couplet 15 of 54

  • ○ Hindwing longer than 22 mm
a ↑
b ↓
  • ○ Hindwing shorter than 22 mm

4 Male only
  • Coenagrionidae: Key couplet 16 of 54

  • ○ Abdominal segments 2-4 black and blue or blue-grey above

    ⇒ species: Large Riverdamsel (Caliagrion billinghursti) (part)
a ↑
b ↓
  • ○ Abdominal segments 2-4 bronze-black above

    ⇒ genus: Pseudagrion

5 Male only
  • Coenagrionidae: Key couplet 18 of 54

  • ○ Synthorax blue and black
a ↑
b ↓
  • ○ Synthorax with extensive brown to yellow areas, sometimes pruinescent

6 Male only
  • Coenagrionidae: Key couplet 20 of 54

  • ○ Face dull brown
    ○ Abdominal segments 8-9 pale bluish grey, pruinescent

    ⇒ species: Dusky Riverdamsel (Pseudagrion jedda)
a ↑
b ↓
  • ○ Face yellow or orange-yellow
    ○ End of abdomen either blackish brown, often pruinescent, or bright blue on much of segments 8-9

7 Female only
  • Coenagrionidae: Key couplet 23 of 54

  • couplet drawing
  • ● Abdominal segments 3-5 brownish black above except for narrow, pale band at extreme base
    ● Lateral margin of dark upper surface almost straight
a ↑
b ↓
  • couplet drawing
  • ● Dark pigmentation on abdominal segments 3-5 less extensive, tapered to rounded in front, narrowing to back, abruptly expanded distally, so that lateral pale areas are clearly visible from above, and lateral margin is sinuate

8 Female only
  • Coenagrionidae: Key couplet 24 of 54

  • ○ 12-15 postnodal crossveins
a ↑
b ↓
  • ○ 16-19 postnodal crossveins

    ⇒ species: Dusky Riverdamsel (Pseudagrion jedda)

9 Male only
  • Coenagrionidae: Key couplet 40 of 54

  • ○ Extensive dull orange to red markings on head, thorax and anterior abdomen

    ⇒ species: Red & Blue Damsel (Xanthagrion erythroneurum)
a ↑
b ↓
  • ○ No such markings on thorax or abdomen

10 Male only
  • Coenagrionidae: Key couplet 41 of 54

  • ○ Synthorax with extensive brown or yellow areas, sometimes pruinescent

    ⇒ genus: Pseudagrion
a ↑
b ↓
  • ○ Synthorax blue and black

11 Male only
  • Coenagrionidae: Key couplet 43 of 54

  • couplet drawing
  • ● Ac of hindwing aligned, or almost aligned, with basal antenodal crossvein

    ⇒ species: Large Riverdamsel (Caliagrion billinghursti) (part)
a ↑
b ↓
  • couplet drawing
  • ● Ac of hindwing beyond alignment of basal antenodal crossvein

    ⇒ genus: Pseudagrion

12 Female only
  • Coenagrionidae: Key couplet 49 of 54

  • couplet drawing
  • ● Ac of hindwing aligned with basal antenodal crossvein

    ⇒ species: Large Riverdamsel (Caliagrion billinghursti) (part)
a ↑
b ↓
  • couplet drawing
  • ● Ac of hindwing beyond alignment with basal antenodal crossvein

    ⇒ genus: Pseudagrion

Australian distribution