Austroaeschna atrata - Mountain Darner

Male identification: Large dark dragonfly with faint,dusky,indistinct markings on top of thorax appearing dark from distance. Bright markings restricted to sides of thorax in loose collection of shapes. Abdomen appears banded above when viewed from distance, with broad pale mediodorsal patches on segments 3,4,5,6,7,9. Other smaller spots not obvious. Pale lateral spots of abdominal segments are separated from dorsal patches. Segment 10 with dorsal rounded horn directed backwards. Inferior anal appendage truncate and deep with sharp apical tooth. Occipital triangle and postgenae yellow. Post clypeus and anterior frons pale forming a broad band with two short bands reaching up onto top of frons from each side without meeting. Pair of very small spots in centre of labrum. Hind margine of occcipital triangle slightly concave to straight. A yellow spot on distal end of both middle and rear femurs.

Female identification: Essentially similar to male. Abdomen thicker and has more pale patches than male creating a brighter and more reticulated appearance. Hind margine of occipital triangle is flanked by large brown subtriangular flaps directed backwards and meeting at tips.

Similar species: Unique among Darners due to lack of pronounced markings on top of thorax. Forms species pair with subapicalis from which it can be separated with care using the following criteria. Lack of antihumeral marking on top of thorax. Pale lateral spots on segments 3,4,5 and 6 are separated from dorsal patches whereas in subapicalis they are joined. Dorsal horn on segment 10 directed backwards not upright, smaller spots on femur, shape of inferior appendage, shape of posterior margine of occipital triangle.

Behaviour: Flies low over water, hovering periodically over areas of still water and weaving in and out of fallen logs and branches.

Distribution: Found in hill-country areas of Victoria, mostly between about 400 and 1200m altitude.

Australian State distribution (from CSIRO Entomology)

Habitat: Fast flowing forested rivers in the hills, with a surplus of fallen timber and branches, in which larvae reside.

Status: Uncommon and localised.

Flight period: December to April