What Bug Is That? The guide to Australian insect families.

Logo: What Bug Is That? Logo: Taxonomy Research & Information Network



This is the largest family in Anisoptera and the largest family in Australian Odonata, although Libellulidae are less dominant here than in many countries. There are 56 Australian species in 27 genera, Endemism is low, with four-fifths of species occurring also elsewhere. Some species such as Pantala flavescens are true wanderers; individuals roam the tropics and have no home range. Most species breed in still water.

There have been many attempts to divide the Libellulidae into subfamilies or tribes based on morphological characters, usually of the wing venation, but all have proven unsatisfactory. Clearly, there has been much convergent or parallel evolution within this family, perhaps associated with life style and habitat. Molecular phylogenetic analyses are slowly resolving the issues but much work remains to be done. One or two natural groups can be identified with some degree of confidence, and in the past some of these have been treated at family level, but to do so always leaves a clearly paraphyletic remainder. For the most part any classification into subfamilies is contentious because whatever characters are used for classification a large number of seemingly 'good' characters must be reinterpreted as convergent. The description below merely clusters the genera, for convenience, into sets of similar-looking species.

A useful feature of Libellulidae to distinguish it from Corduliidae is that the antenodal crossveins (i.e., in the space bounded by costa, radius, wing base and nodus) are in strict alignment and all of equal thickness. The two primary crossveins, so prominent in most other families, usually cannot be distinguished. Often, too, the sectors of the arculus are joined together on a short stalk, and an anal loop (the group of cells behind the triangle) is well developed. In many genera the anal loop is sock shaped, like a map of Italy, but that should not be regarded as a family-level character.

Nannophlebia and Tetrathemis are very small libellulids in which the crossvein that divides the discoidal cell into a triangle and hypertriangle meets the posterior sector of the arculus before vein MA turns distalwards, thereby making the "triangle"  four-sided. This trait may be functionally associated with small size as it also occurs in the very different but equally small Nannophya and Nannodiplax and in the small corduliids of subfamily Cordulephyinae. Nannophlebia and Tetrathemis are black and yellow, like corduliids.

Brachydiplax , Nannophya and Nannodiplax are small dragonflies with extensive areas of body colour in shades of red or blue. Brachydiplax inhabits still or sluggish waters while the four species of Nannophya are swamp specialists. Nannodiplax is one of the smallest known libellulids. Larger than these, but still quite small, are the five species in Diplacodes . D. bipunctata (male red with small black markings) and D. haematodes (male bright scarlet) are common and widespread: the final antenodal in the forewing is incomplete, running obliquely from the costa to subcosta; the wings at rest are held about 30 degrees below the horizontal. Austrothemis are somewhat similar in size, the male red and black, the wings depressed at rest, with a more open venation, no stalk to the sectors of the arculus, and a small dark mark at the base of the hindwing. Rhodothemis (1 sp.) is another widespread red species of similar form although somewhat larger, with more than nine antenodal veins, the last of which is incomplete.

Aethriamanta , Macrodiplax and Urothemis are another group of small libellulids with bright red males. The females, as is common across the family, are in soft shades of yellow, with some black markings. The venation in this group of small dragonflies is very open, with only a few antenodals and few crossveins. The two primary antenodals are weak but discernible, and the sock-shaped anal loop is well developed. The range of Macrodiplax cora encompasses much of tropical Asia and the Pacific. In Australia it extends from the south west of WA, across the coastal north, to as far south as Sydney on the east coast.  

Orthetrum is a widespread genus of the temperate and tropical old world. Males of the seven Australian species vary much in colour, from black and yellow to powder blue or red. O. caledonicum is a very common powder blue species on ponds everywhere. This colour is not structural but comes about by wax deposition. Young males acquire it gradually and it can be scraped off without apparent damage to the animal. The underlying body colour is yellow and black. Orthetrum are readily distinguished from the genera mentioned above by their larger size, the distal antenodal complete. Agrionoptera (2 spp.), Lathrecista (1 sp.), Potamarcha (1 sp.) and the endemic Notolibellula (1 sp.) are of somewhat similar form and sometimes placed in the same subfamily.

Crocothemis nigrifrons is our only representative of this very widespread old world genus. It has a dark head and thorax with a powder-blue abdomen in males, and is widely distributed in all coastal regions. Huonia melvillensis (pale green and black, far north NT) represents the southern limit of that largely Indonesian and New Guinean genus.

A number of not very closely related genera have coloured markings on the wings:   Neurothemis (2 Australian spp.: one with metallic brown wingbases, the other with extensive red to beyond the nodus), Rhyothemis (5 spp.: two with metallic black, one with metallic blue, and two with non-metallic brown and yellow wing markings), Tholymis (1 sp.: wings with a brown patch and a milk white circle), Camacinia (1 sp.: wings with a long, brown costal stripe and brown tips), and Tramea (4 spp.: with red saddlebag marks on the hindwings). Most of these species are tropical. Of these, T. loewii is wide ranging and widespread, and can be found on ponds and dams in almost all districts, also north into Indonesia and east to the western Pacific.

Hydrobasileus brevistylus is a large northern species that from its black and yellow colour could be mistaken for a member of Corduliidae, but the venation is libelilid.  Zyxomma (3 species), with similar wing venation, are dull brown and crepuscular. Not so Pantala flavescens (males red, females yellow, each with small black marks, the wings clear of markings). This species is a compulsive wanderer. It regularly crosses oceans and will perch on ships at sea. All genera in this last group have a very broad hindwing, adapted for gliding.

  • Diplacodes bipunctata larvae

  • Nannophya occidentalis

  • Diplacodes haematodes

  • Diplacodes bipunctata

  • Eusynthemis nigra

  • Lathrecista asiatica

  • Orthopterum caledonicum

  • Macrodiplax cora