Males have a head that is strongly raised on its upper side.
In the described male and female, the head and thorax are dark reddish brown. The abdomen is mottled greyish brown and beige and has three pairs of humps on its back.
Male Austrarchaea smithae have a short brush of hairs on the front of their elongated chelicerae. The described female lacks this brush. Similar body colours and abdominal humps accompany a difference in the fine structure of the jaws.
The 2010 type material from Mount Wilson was found in elevated leaf litter beneath grass trees at 948 metres, in densely undergrown eucalypt forest bordering rainforest. Within a broad forest landscape, the specimen labels preserve a much smaller place in which to look for the spider.
A 2020 study overlaid museum occurrence records with maps of the 2019–2020 bushfires. All known recorded sites for this species overlapped the mapped burnt area, and the authors called for field checks. Information preserved with specimens helps identify places to survey after fire.
An extinction-risk assessment has not been added yet.
The 2020 fire assessment reported that the confirmed Mount Wilson occurrence records overlapped the mapped 2019–2020 burnt area. The authors suggested that spiders collected from elevated litter could be particularly susceptible to intense fire. Their broader recommendations included field assessment and protection of nearby unburnt areas.