Blue Skimmer (Orthetrum caledonicum)

The Blue Skimmer (Orthetrum caledonicum) is a dragonfly species of the family Libellulidae, which contains 56 species in Australia.

The identification key to the family Libellulidae consists of 67 couplets, 12 of which are pertinent to Orthetrum caledonicum. 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.

#	Family	Species	Couplet No.
	Libellulidae	Blue Skimmer (Orthetrum caledonicum)	Libellulidae: Key couplet 1 of 67 ● Distal antenodal of forewing complete, both costal and subcostal sections present a ↑ Libellulidae: Key couplet 2 of 67 ● Anal loop present b ↑ Libellulidae: Key couplet 9 of 67 ● Anal loop well developed, generally stocking-shaped, usually closed at tip b ↑ Libellulidae: Key couplet 14 of 67 ○ Not as above b ↑ Libellulidae: Key couplet 15 of 67 ● Base of hindwing triangle at or proximal to arculus ○ Top of frons, if metallic, dully so b ↑ Libellulidae: Key couplet 20 of 67 ○ Smaller dragonflies, hindwing up to 40 mm long ○ Wings patterned or hyaline b ↑ Libellulidae: Key couplet 21 of 67 ● Subtriangle of forewing with three or more cells b ↑ Libellulidae: Key couplet 24 of 67 ● Forewing triangle crossed b ↑ Libellulidae: Key couplet 27 of 67 ○ Hind margin of eye uniformly curved b ↑ Libellulidae: Key couplet 28 of 67 ● Some double cells between IR3 and Rspl ⇒ genus: Orthetrum a ↑ Libellulidae: Key couplet 29 of 67 ○ Hindwing clear at base b ↑ Libellulidae: Key couplet 34 of 67 ● Yellow with black markings, side of synthorax yellow, sutures narrowly lined black ○ Thorax and abdomen of male becoming pruinescent blue when mature, the mature female slightly pruinescent ⇒ species: Blue Skimmer (Orthetrum caledonicum) b ↑
1			Libellulidae: Key couplet 1 of 67 ● Distal antenodal of forewing complete, both costal and subcostal sections present a ↑ b ↓ ● Distal antenodal of forewing incomplete, only the costal section present
2			Libellulidae: Key couplet 2 of 67 ● Hindwing lacking anal loop ⇒ genus: Nannophya a ↑ b ↓ ● Anal loop present
3			Libellulidae: Key couplet 9 of 67 ● Anal loop rounded, poorly developed, of three to five cells a ↑ b ↓ ● Anal loop well developed, generally stocking-shaped, usually closed at tip
4			Libellulidae: Key couplet 14 of 67 ○ Small (hindwing c. 25 mm) ● Synthorax and abdomen black with well-defined pale yellowish green markings ⇒ species: Forestwatcher (Huonia melvillensis) (part) a ↑ b ↓ ○ Not as above
5			Libellulidae: Key couplet 15 of 67 ● Base of hindwing triangle just beyond to well beyond arculus ○ Top of frons brilliant metallic blue or green, particularly in male a ↑ b ↓ ● Base of hindwing triangle at or proximal to arculus ○ Top of frons, if metallic, dully so
6			Libellulidae: Key couplet 20 of 67 ○ Large dragonflies, hindwing 45 mm or longer, wing membrane extensively marked with reddish- or blackish-brown ⇒ species: Black Knight (Camacinia othello) (part) a ↑ b ↓ ○ Smaller dragonflies, hindwing up to 40 mm long ○ Wings patterned or hyaline
7			Libellulidae: Key couplet 21 of 67 ● Subtriangle of forewing single-celled a ↑ b ↓ ● Subtriangle of forewing with three or more cells
8			Libellulidae: Key couplet 24 of 67 ○ Forewing triangle free a ↑ b ↓ ● Forewing triangle crossed
9			Libellulidae: Key couplet 27 of 67 ● Small tongue-like evagination from central hind margin of eye ⇒ species: Swamp Flat-Tail (Austrothemis nigrescens) (part) a ↑ b ↓ ○ Hind margin of eye uniformly curved
10			Libellulidae: Key couplet 28 of 67 ● Some double cells between IR3 and Rspl ⇒ genus: Orthetrum a ↑ b ↓ ● Only one row of cells between IR3 and Rspl ⇒ species: Red Arrow (Rhodothemis lieftincki) (part)
11			Libellulidae: Key couplet 29 of 67 ● Small reddish-brown to yellowish-brown spot at base of hindwing a ↑ b ↓ ○ Hindwing clear at base
12			Libellulidae: Key couplet 34 of 67 ● Black with yellow markings, side of synthorax substantially dark ⇒ species: Speckled Skimmer (Orthetrum balteatum) a ↑ b ↓ ● Yellow with black markings, side of synthorax yellow, sutures narrowly lined black ○ Thorax and abdomen of male becoming pruinescent blue when mature, the mature female slightly pruinescent ⇒ species: Blue Skimmer (Orthetrum caledonicum)