Males have a more conical head that is elevated at the rear.
In the described male and female, the head and thorax are dark reddish brown, and the legs have darker rings. The abdomen is mottled greyish brown and beige.
Austrarchaea dianneae has three pairs of small humps on the upper abdomen. Males also have a brush-like patch of short hairs on the front of the jaws. Fine structures are useful when comparing this spider with similarly coloured relatives.
In April 2010, researchers found two closely related species near Binna Burra in Lamington National Park, Australia. Alongside numerous A. dianneae they collected one juvenile Austrarchaea nodosa. The 2011 paper discussed this discovery in an area long assumed to contain only one archaeid species.
Identification combined comparisons of adult morphology with DNA evidence from juveniles. DNA extracted from leg tissue was analysed across a mitochondrial region containing two genes. Genetic information allowed immature spiders to be matched to species. Carefully distinguishing the small spiders collected in one forest showed that A. dianneae and A. nodosa lived together at the locality.
An extinction-risk assessment has not been added yet.
The authors reported in 2011 that, although restricted in distribution, this species was abundant in Tamborine National Park and also occurred in protected habitat in Lamington National Park. They did not then consider it of conservation concern. Maintaining forest at its documented sites and checking present-day occurrence would help update that historical appraisal.