Suborder Anisoptera
Family Libellulidae

Family Libellulidae figure 1

The Libellulidae are the largest anisopteran family, including 35 genera known from the Papuan region. They are invariably the dominant group of Anisoptera in almost any ecosystem, with the exception of very high altitudes, which in New Guinea are dominated by Corduliidae.

Among Anisoptera, Libellulidae embody the greatest variety in form and colour, though there are not so many species with metallic body colors as in the Corduliidae and Synthemistidae. The eyes are almost always contiguous by a long eye-seam at the top of the head (the Sympetrinae, with eyes touching at a single point, is a noteworthy exception). The mesopleural suture almost always has a distinctive S-curve in the middle, unlike that found in Corduliidae, which is usually straight. The abdomen comes to a roof-like peak along its mid-dorsal ridge (especially on the middle segments), unlike Corduliidae and Aeshnidae, which have the abdomen much more cylindrical. There is no anal triangle or anal angle in the hindwing of the male and there are no auricles on S2 of the abdomen.

Libellulidae are perchers, landing on exposed twigs, stems, branches or most anything else they can find which overlooks their feeding, mating, or oviposition sites. Their legs are so strongly positioned aslant (the front legs tiny and the hindmost pair quite long) that a libellulid can comfortably hold onto a fully vertical stem while easily keeping its body in a horizontal position.

The larvae are stocky and, according to Needham & Westfall (1954), so similar to the larvae of the Corduliidae that no single character has been found that will universally separate them.

 

Key to the genera of Papuan Libellulidae

1 Costal side of forewing triangle broken (below, upper left); anal loop small or lacking, not stocking-shaped (below, lower left)2

- Costal side of forewing triangle straight or nearly so (below, upper right); anal loop usually well-developed (except Nesoxenia), usually stocking-shaped (below, lower right)8

 

Family Libellulidae figure 2

2 Tiny dragonflies (abd and hindwing each < 15 mm), body colors red and black (male) or yellow, red and black (female). 5 antenodals in forewing, 4 in hindwing; pterostigma supported by only the proximal brace vein in row below it; anal area of hindwing broad, widest basal to hindwing triangle Nannophya Rambur (1 sp.)

- Small to medium-sized dragonflies (abd 16.5-25, hindwing 18-31 mm), body colors mainly black and yellow, or brown and yellow. At least 6 antenodals in forewing, 5 in hindwing; pterostigma supported by at least two crossveins in row below it; anal area of hindwing reduced, widest distal to hindwing triangle subfamily Tetrathemistinae 3

3 Hindwing lacking anal loop (below) 4

- Anal loop present (may be composed of as few as 3 cells) (above, left) 5

Family Libellulidae figure 3
Hw lacking anal loop (Tapeinothemis).

4 Hindwing with only one cell-row between anal vein and hind margin of wing, resembling in this feature the forewing. Two crossveins in cubital space of hindwing. Around 8 antenodal crossveins in forewing. hindwing triangle small, about half the length of the supra-triangle, separated from arculus by a distance equal to its own length. Ground-color of thorax shining metallic greenish bronzy-black, marked with four or five chrome-yellow spots. Distribution: Solomon Islands Tapeinothemis Lieftinck (1 sp.)

- Hindwing with two staggered cell-rows between anal vein and hind margin of wing. One crossvein in cubital space of hindwing. Around 12 antenodal crossveins in forewing. hindwing triangle larger, nearly equal in length to supra-triangle, separated from arculus by a distance much shorter than the length of basal side of triangle. Ground-color of thorax yellow, with a broad black antehumeral band and a narrow black band crossing the mesepimeron. Distribution: New GuineaRisiophlebia Cowley (1 sp.)

5 Distal antenodal crossvein of Fw complete (below, left). Yellow and black dragonflies. Anal loop rounded, poorly developed, of 3-5 cells. 6

- Distal antenodal crossvein of Fw incomplete (below, right). Brown and dirty- yellowish dragonflies. Anal loop well developed, elongate, usually closed at tip. 7

Family Libellulidae figure 4

6 Basal side of hindwing triangle close to or at arculus (below, left). One crossvein in cubital space of hindwing. Male thorax patterned in irregular black stripes over meso- and metapleural sutures, the latter not parallel-sided, and usually with a smaller black stripe descending from upper end of mesopleural suture to metathoracic spiracle Nannophlebia Selys (20 sp. & ssp.)

- Basal side of hindwing triangle well beyond arculus (below, right). More than one crossvein in cubital space of hindwing. Male thorax patterned in broad, usually straight-edged black stripes over meso- and metapleural sutures, and with no smaller stripe descending from upper end of mesopleural suture to metathoracic spiracleTetrathemis Brauer (1 sp., 6 ssp.)

 

Family Libellulidae figure 5

7 Second Cux of front wing not coinciding with the proximal angle of triangle, so that no regular subtriangle is formed; Costal side of front wing triangle broken, the elements about equal in length; Anal field of hindwing very narrow, with only 2 rows of cells between 1A and the anal margin, and with no distinct closure to anal loop (below, left)Bironides Förster (4 sp.)

- Second Cux of front wing coinciding (or nearly so) with the proximal angle of triangle, so that a regular subtriangle is formed; Costal side of front wing triangle only slightly fractured near its distal end; Anal field of hindwing broader, with 3 rows of cells between 1A and the anal margin, and with a complete, enclosed, elongate anal loop, whose outer angle extends two cells distad to the triangle (below, right) Microtrigonia Förster (3 sp.)

 

Family Libellulidae figure 6

8 Nodus of forewing beyond midpoint of wing (below) 9

- Nodus of forewing at midpoint of wing or further basad 12

 

Family Libellulidae figure 7
Nodus beyond midpoint of Fw (Huonia).

9 Anal area of hindwing greatly expanded (below, left) subfamily Trameinae (Part) 32

- Anal area of hindwing not greatly expanded (below, right) 10

 

Family Libellulidae figure 8

10 One or two Cux in hindwing subfamily Trithemistinae 11

- More than two Cux in hindwing Lyriothemis Brauer (2 sp.) (Part)

11 Discoidal field of forewing containing 3 rows of cells, occasionally a 4th, between triangle and level of the origin of IR3 (below, left). Thorax blackish, male abdomen dark brown to black with some blue pruinosity. Hindwing with dark basal patch, extending into base of anal loop. Single regional species with black terminalia in both sexes Trithemis Brauer (1 sp.)

- Discoidal field of forewing containing 2 rows of cells between triangle and level of the origin of IR3 (below, right). Thorax blackish, males (at least) marked with bright yellow or green spots or stripes. Hindwing hyaline at base. All known species with yellow terminalia in both sexesHuonia Förster (16 sp. & ssp.)
and Lanthanusa Ris (5 sp.)

 

Family Libellulidae figure 9

12 Arculus at or distal to second antenodal crossvein, usually in both wings, but at least in hindwing subfamily Libellulinae 13

- Arculus between first and second antenodal crossveins 20

13 Distal antenodal crossvein of forewing incomplete, only the costal section present (below, left). Side of thorax patterned in a strongly-contrasting "Y-I-Y" pattern (below), which may become obscured by pruinosity in mature specimens 14

- Distal antenodal crossvein of forewing complete, both costal and subcostal sections present (below, right). Side of thorax not patterned as described above. 15

 

Family Libellulidae figure 10

 

14 Hw triangle traversed by crossvein. Vein R3 in forewing strongly undulate (below). Thorax becoming pruinescent with age, abdomen turning blackish with bluish pruinosity. Anterior branch of male genital hamule low and hooked, and inconspicuous. Lateral margins of female S8 expanded into conspicuous leaflike lobes Potamarcha Karsch (1 sp.)

- Hw triangle free. Vein R3 in forewing not strongly undulate. Thorax not becoming pruinescent with age, abdomen remaining reddish. Anterior branch of male genital hamule long, erect, and curved only at tip. Lateral margins of female S8 unmodified Lathrecista Kirby (Part) (1 sp., 4 ssp.)

 

Family Libellulidae figure 11
Vein R3 (Potamarcha).

15 Hindwing triangle distinctly beyond arculus, by a distance approximately equal to, or greater than, upper portion of arculus itself. Anal area of hindwing not greatly expanded, widest part of hindwing usually at level of origin of IR3 16

- Hindwing triangle at or only slightly distal to arculus. Anal area of hindwing usually more expanded, widest part of hindwing usually at or before level of toe of anal loop 18


16 Anal loop rounded, poorly developed, of 3-5 cells (below, left). Only 1-2 cell-rows between anal vein and hind margin of hindwing, between base and level of arculus Nesoxenia Kirby (1 sp., 7 ssp.)

- Anal loop well developed, elongate, usually closed at tip (below, right). 3 or more cell-rows between anal vein and hind margin of hindwing, between base and level of arculus 17

 

Family Libellulidae figure 12

17 Base of forewing with 1 or 2 cell-rows between anal vein and hind margin of wing, between base and proximal end of subtriangle; forewing subtriangle of 2 or 3 cells. Slimmer, light-bodied dragonflies, venter of S4 approx. 2 mm across, hindwing < 37 mmAgrionoptera Brauer (2 sp., 9 ssp.)


- Base of forewing with up to 3 or 4 cell-rows between anal vein and hind margin of wing, between base and proximal end of subtriangle; forewing subtriangle of 4 to 6 cells. Stouter, heavier-bodied dragonflies, venter of S4 approx. 5 mm across, hindwing approx. 40 mm or greater Protorthemis Kirby (3 sp.)

18 Dorsum of frons not brilliantly metallic. Ground color of thorax brown, green, or reddish, often with darker stripes or lighter diagonal bands, in some species turning blackish with maturity and acquiring pruinosity, but never with a metallic lustre Orthetrum Newman (12 sp. & ssp.)

 

- Dorsum of frons brilliant metallic green or blue. Ground color of thorax variable 19

19 More than 2 crossveins in cubital space of hindwing. Sides of thorax either black with broad, transverse yellow stripe, or pale in color with transverse brown lines or stripes; male abdomen bright red, female abdomen yellowish
Lyriothemis Brauer (2 sp.) (Part)

- Only one crossvein in cubital space of hindwing. Thorax and abdomen chiefly
black, thorax with metallic blue or green lustre and marked with spots and stripes of pale green; in practically every known species, interpleural suture below metathoracic spiracle is pale (at least along anterior edge), and (except D. cyrene) a dark stripe descends along upper portion of interpleural suture to touch upper edge of spiracle Diplacina Brauer (20 sp. & ssp.)

20 Only 5 antenodal crossveins in hindwing. Sectors of arculus, particularly in forewing, fused for only a short distance, separating well before level of second antenodal crossvein (below, left) subfamily Urothemistinae 21

- 6 or more antenodal crossveins in hindwing. Fusion of sectors more extensive, stalk extending nearly to, or well beyond, level of second antenodal crossvein (below, right)23

 

Family Libellulidae figure 13

21 Subtriangle of forewing single-celled (above, left) Aethriamanta Kirby (2 sp.)

- Subtriangle of forewing with 2-3 cells 22

22 Fw usually with 7 or 8 antenodals, 7 postnodals. Postnodal crossveins of second row evenly spaced near pterostigma. Thorax reddish or coppery-brown, sutures darker. Abdomen of male red above except for mid-dorsal dark spots on distal segments. Basal brown or amber patch of hindwing variable, usually not extending out much further than crossveins in cubital space. Vulvar scale of female elongate, extending the length of S9 Urothemis Brauer (3 sp.)

- Fw with 6 antenodals, 5 postnodals. The crossvein under the proximal end of the pterostigma has a vacant space, as long as 2 or 3 normal cells, between it and the 3 postnodal crossveins of the second row (below). Thorax yellowish marked with sharply-defined black sutures. Abdomen of male orange-red, with broad mid-dorsal black stripe. hindwing with large brownish basal patch extending as far as triangle. Macrodiplax Brauer (1 sp.)

 

Family Libellulidae figure 14
Space before Pt, (Macrodiplax).

23 Basal side of forewing subtriangle poorly defined; subtriangle, if recognizable, containing more than 3 cells. hindwing often greatly expanded at base, widest at level of arculus or even futher basad. Usually more than one row of cells between IR3 and Rspl, or a mixture of single- and double-rows. Vein R3 usually distinctly sinuate subfamily Trameinae 32

- Subtriangle of forewing with 1-3 cells, its basal side well-defined. hindwing not greatly expanded at base, typically not distinctly wider at arculus than at toe of anal loop. Other characters variable 24

24 Usually more than one row of cells between IR3 and Rspl, or a mixture of single- and double-rows. Vein R3 usually distinctly sinuate. Wings with variable, yellowish brown patch between triangle and nodus of hindwing, sometimes very faint Tholymis Hagen (1 sp.) (Part)

- Only one row of cells between IR3 and Rspl (occasionally a double-row for one cell-length in some Zyxomma). Vein R3 variable. Wings not marked as described above 25

25 Vein R3 distinctly sinuate (below). Abdomen narrowing abruptly within the length of S3. Insects of shade-loving or crepuscular habit Zyxomma Rambur (3 sp.) (Part)

- Vein R3 usually running smoothly to wing margin. Abdomen tapering progressively
from S3 to tip. Insects of typical diurnal habit 26

 

Family Libellulidae figure 15
R3 sinuate (Zyxomma).

26 Male frons metallic blue or metallic green dorsallysubfamily Brachydiplacinae 27
[excluding the tiny, red-and-black Nannophya]


- Vein R3 usually running smoothly to wing margin. Abdomen tapering progressively from S3 to tip. Insects of typical diurnal habit 28

27 More than 8 antenodal crossveins in forewing. Male with pair of conspicuous ventral metathoracic spines. hindwing triangle located far beyond arculus. Habitat: mangrove swamps Raphismia Kirby (1 sp.)

- Fewer than 8 antenodal crossveins in forewing. Male without conspicuous spines on venter of metathorax. hindwing triangle located at arculusBrachydiplax Brauer (2 sp.)

28 Discoidal field of forewing with two rows of cells, or three rows immediately followed by two rows, from triangle to about the level of fork of IR3, or further 29

- Discoidal field of forewing with three or more rows of cells, from triangle to the level of fork of IR3, or further 31

29 Larger dragonflies, hindwing > 30 mm; 10.5-12.5 antenodals in forewing Rhodothemis Ris (3 sp.)

- Small to tiny dragonflies, hindwing < 28 mm; 6-9 antenodals in forewing 30

30 Tiny red and greenish dragonflies, hindwing < 16 mm. 6 antenodals in forewing; distal antenodal crossvein complete. Wing apices without dark pigment Nannodiplax Brauer (1 sp.)

- Small to very small dragonflies, hindwing > 17 mm. More than 6 antenodals in forewing; distal antenodal crossvein incomplete. Smallest species has black wing apices, larger species have hyaline wing apices Diplacodes Kirby (4 sp.)

31 Hindwing triangle traversed by one or more crossveins. More than 1 Cux in hindwing (below). Males of all species with extensive areas of pigmentation on wings, extending in forewing from base at least to proximal side of triangle, usually to nodus and beyond; female wings either patterned like male or with diffuse areas of dark pigment and with apices also dark. forewing triangle with minimum of two crossveins, usually with innumerable irregular crossveins filling the cell. Most species with multiple, irregular cell rows in discoidal field of forewing Neurothemis Brauer (8 sp. & ssp.)

- Hindwing triangle free. Only 1 Cux in hindwing. Wings lacking extensive dark pigment, with at most a flush of dark brown or reddish-yellow at extreme wing base, apices hyaline. forewing triangle with at most a single crossvein. Three regular cell rows between forewing triangle and level of the origin of IR3 Crocothemis Brauer (2 sp.)

 

Family Libellulidae figure 16
Hw triangle, 2 Cux (Neurothemis).

32 Hindwing triangle traversed by one or more crossveins. Distal antenodal crossvein complete or not. Large species, hindwing > 40 mm. Male with extensive areas of brown pigmentation on both pairs of wings, at least (invariably) with uninterrupted band of dark pigment throughout costal field from base to nodus Camacinia Kirby (2 sp.)

- Hindwing triangle almost always free (the exception being some specimens of Hydrobasileus). Distal antenodal crossvein incomplete. Size and wing color variable, but not with the above combination of characters 33

33 Tip of anal loop usually open on one or both sides of mid-vein, the bounding veins of loop extending to wing margin, occasionally closed, the bounding veins meeting mid-vein at wing margin (below, left). Species of shade-loving or crepuscular habit 34

- Tip of anal loop closed, the bounding veins meeting mid-vein one row of cells away from wing margin (below, right). Species of open areas, sun-loving, great gliders 35

 

Family Libellulidae figure 17

34 Abdomen tapering progressively from S3 to tip. hindwing with variable, yellowish brown patch between triangle and nodus, sometimes very faint. Male abdomen orange-brown Tholymis Hagen (1 sp.) (Part)

- Abdomen narrowing abruptly within the length of S3. Apices of wings variably darkened, sometimes hyaline, remainder of wing hyaline except for dark flecks at extreme base and, in some, a dark costal band, or suffused with yellowish brown throughout. Male abdomen dull brown to blackish brown, sometimes coated in white pruinosity Zyxomma Rambur (3 sp.) (Part)

35 Smaller dragonflies, hindwing typically < 36.0 mm. Most species extensively patterned across forewing and hindwing (below), in hindwing at least as far as proximal side of triangle, more usually covering the greater portion of both wings
Rhyothemis Hagen (13 sp. & ssp.)


- Larger dragonflies, hindwing typically > 38.0 mm. Dark wing pigmentation, when present, usually confined to basal area of hindwing (except in some Hydrobasileus), not, or only rarely (some Tramea), extending beyond proximal side of hindwing triangle 36

 

Family Libellulidae figure 18
Sample wing patterns of Rhyothemis.

36 Hindwing with 2 Cux. Face and frons golden yellow, sometimes flushed slightly orange. Wings essentially hyaline, slightly yellowish at extreme base and often with small round brown spot at apex. Black markings on sides of thorax, if any, reduced to small spot over metathoracic spiracle, and over upper portion of meso- and metapleural sutures. Male abdomen brownish yellow to orange-red, with black dorsal markings, these markings broadest on S8-9 Pantala Hagen (1 sp.)

- Hindwing with 1 Cux. Face and frons not yellow. Wings either enfumed saffron or reddish, or marked with a dark reddish-brown patch at base of hindwing (sometimes reduced to a few cells in cubito-anal field). Black markings on thorax variable. At least apical segments of abdomen marked with extensive areas of black 37

37 Wing membrane hyaline except for dark reddish-brown patch at base of hindwing (reduced in one subspecies to a few cells in cubito-anal field) and variable, small reddish patch at base of forewing, often lacking. Male abdomen orange-red, red, or reddish brown, the last few segments marked with black. Thorax dark reddish or brownish, with darker markings, if any, over metathoracic spiracle and meso- and metapleural sutures Tramea Hagen (9 sp. & ssp.)

- Wings enfumed saffron or reddish throughout, extent of darker markings variable. Abdomen black, with dorsal pairs of yellow spots, or red with black dorsal and lateral sutures. Thorax with complete, broad black bands over lateral sutures
Hydrobasileus Kirby (2 sp.)

 

 

 

 

Representative Papuan Libellulidae
Family Libellulidae figure 19