Suborder Anisoptera
Family Aeshnidae

Aeshnids are generally the largest Anisoptera in any ecosystem. They are very strong flyers. Many species are crepuscular in habit or frequent deeply shaded forest. They generally do not perch on branch tips but instead hang vertically under an overhanging bough or other shaded cover. These factors combine to make the members of this family relatively scarce in collections. Most species breed in still or very quiet waters.

Unlike the gomphids, aeshnid larvae are not burrowers. Rather, they are active climbers and use jet-propulsion to move quickly through the water. They can be found among aquatic plants, submerged roots, branches and other situations which allow them to move about quickly. They are active hunters, not passive ambushers. As the adults are such large and strong flyers, their powers of dispersal are great; and aeshnid larvae are apt to be found in any body of water, large or small, which can provide enough food in the form of insects, tadpoles and fish fry, to keep them growing. Some species have been known to breed in such tenuous situations as tree-holes, drainage ditches and rain barrels.

Aeshnid adults are large, mostly clear-winged and fast and some species can be seen flying in large assemblages far overhead. In lowland areas of New Guinea the author has witnessed swarms of three and four different species flying together after sunset. In these situations, the difficulty of collecting them in the approaching darkness is somewhat offset by the sheer numbers of individuals flying back and forth.

In total, seven aeshnid genera (including Hemianax, which probably needs to be taken off the list) have been attributed to the Papuan region.

Anax maclachlani
Anax maclachlani

 

Key to the genera of Papuan Aeshnidae

1 Last prominent fork of IR3 at or near level of distal end of Pt in both wings (below upper left); anal margin of hindwing rounded in both sexes, male lacking anal triangle and auricle (below, lower left)2

- Prominent fork of IR3 near or proximal to level of basal end of Pt (below, upper right); anal margin of hindwing rounded in female, angulated in male, forming anal triangle; male with auricles (below, lower right)3

 

Family Aeshnidae figure 1

2 Sides of tergites 7-9 in males, 4-9 or 5-9 in females, with strong supplementary longitudinal ridge Anax Leach (9 sp.)

- Sides of tergites evenly rounded in males, strongly ridged on tergites 7-8 or 7-9 in females Hemianax Selys (1 sp.)

3 Space between CuP and 1A of hindwing slightly and continuously tapering from proximal to distal end, proximal end usually 1, occasionally 1-2, cells wide (below, left) 4

- Space between CuP and 1A of hindwing 2-3 cells wide proximally, narrowing to half or less in width over central third (below, right). Top of frons with black transverse bar along crest 6

 

Family Aeshnidae figure 2

4 Anal triangle of male narrow, 2-celled (below, left) 5

- Anal triangle of male broad or narrow, with three or more cells (below, right); ventral process on S10 of female 2-prongedGynacantha Rambur (13 sp.)

 

Family Aeshnidae figure 3

5 Frons dorsally with or without a definite T-spot (below, left). Colours sombre: abdomen dark brown or black with tiny pale spots. Ventral process on S10 of female 3-pronged (below, left). Slender; males with narrow, almost parallel-sided abdomen and simple, slenderly filiform cerci, which are separated from each other by a distance 3x the width of each cercus at base Agyrtacantha Lieftinck (4 sp.)

 

- Frons dorsally with a definite T-spot (below, right). Colours bright: abdomen reddish-brown spotted with green or yellow. Ventral process on S10 of female 2- pronged (below, right). Male abdomen evenly but distinctly widened from contriction of S3 to S10; cerci generally of more complex structure, usually rather undulated and often toothed and curved; cerci more widely distant, separated from each other by a distance 4x the width of each cercus at base Plattycantha Lieftinck (6 sp.)

 

Family Aeshnidae figure 4

6 Thorax compact, abdomen slender. Side of thorax brown with two broad diagonal stripes of pale green. Male terminalia at least as long as S9-10 taken together Anaciaeschna Selys (4 sp.)

- Thorax and abdomen very robust, thorax strongly keeled above. Side of thorax mainly deep purplish-black. Male terminalia much shorter than S9-10 taken togetherOreaeschna Lieftinck (1 sp.)

 

Family Aeshnidae figure 5

 

Genus Agyrtacantha Lieftinck, 1937

Long slender aeshnids with a compact thorax and cylindrical abdomen, similar in general appearance to Anaciaeschna and Gynacantha. The terminalia are long, thin and fairly simple. Agyrtacantha occurs from Maluku to the Solomon Islands. Four species are known from the region.

Lieftinck (1937a) writes:

They are wood-loving insects with decidedly crepuscular habitations, occuring most abundantly in low country, where they usually assemble in immense numbers at dusk.

 

 

 

 

 

 

 

 

Genus Anaciaeschna Selys, 1878

Lieftinck (1962) writes: '... migratory species with crepuscular habits which breeds in marshes and rice fields.' Anaciaeschna is found in South-east Asia and across the far-flung island groups of the South Pacific.

Family Aeshnidae figure 6

Four species are known from the region.

 

 

Genus Anax Leach, 1815

Anax selysi
Anax selysi

Large to giant-sized primarily greenish dragonflies found principally over ponds or sluggish waters. They are often pioneers of new habitats or temporary waters and many species are widespread.

Six species are known from the region, and a seventh, A. georgius, is known from nearby Timor.

 

 

Genus Gynacantha Rambur, 1842

Gynacantha rosenbergi
Gynacantha rosenbergi

Crepuscular dragonflies, coloured in dull browns and greens and generally lacking distinctive body markings. Size, shape, habits and even the abdominal appendages are so similar between the species that specific identification is generally considered very difficult indeed. Twelve species have been attributed to the region.

The cerci of both sexes (more usually of females) break off very easily upon capture, and apparently even during the regular course of the insect's life.

 

 

Genus Hemianax Selys, 1883

One species, H. papuensis, doubtfully placed in the Papuan fauna. Known from Australia but apparently misnamed based on a misunderstanding of field notes.

 

 

Genus Oreaeschna Lieftinck, 1937

Family Aeshnidae figure 7

A most distinctive aeshnid, principally purplish-black-and-yellow. Large clear yellow marking covering distal half of sides and dorsum of S2. Bases of both wings darkly smoked to first Ax. Frons without T-spot or black frontal ridge. Known from Mount Cycloop, West Papua, and in 1995 was taken by Stephen Richards on Mt. Stolle, Sandaun Province, Papua New Guinea. In 2005 it was taken by H. van Mastrigt and Stephen Richards (Kalkman et al, 2009) in the Foja Mountains.

One other species of Oreaeschna is known from New Caledonia.

 

Plattycantha acuta
Plattycantha acuta

 

Genus Plattycantha Förster, 1908

Three named species are known from New Guinea, and a further three known only from the female, which Lieftinck (1937a, 1942) described without assigning names. Of the genus, Lieftinck (1937a) writes:

So far as is known this genus comprises a number of large, brightly coloured aeshnids, which are apparently confined to the higher mountain zone of New Guinea, contrary to the usual habits of Agyrtacantha, where two of the three known species are typically inhabitants of low-levelled regions... in forest clearings on the southern slope of Mt. Cycloop P. cornuta as well as P. acuta sometimes fly literally by hundreds in the evenings, and then are an easy capture.

The named species are known from Cycloop Mountain, northern West Papua.