The female has a spherical abdomen in side view.
The abdomen lacks projecting dorsal humps.
The female described for Zephyrarchaea robinsi measured 3.69 mm long. Its carapace was 1.23 mm long and 1.97 mm high: taller than its front-to-back length. The front of its chelicerae lacks accessory hairs.
Research on this spider includes juveniles and shed cuticle as well as an adult. The female holotype was caught in a pitfall trap near the summit of Ellen Peak, Western Australia, on 28 May 1996. In November 2007, two juveniles were collected from elevated leaf litter beneath sedges on the same mountain at 1,007 metres.
The 2012 review also lists juvenile moulted cuticle collected near a waterfall on the shaded southern slope of Pyungoorup Peak in August 2008. At Bluff Knoll, juveniles were collected at separate sites at 877 and 897 metres in June 2010. Small bodies and a shed skin document this spider’s occurrence across several mountain peaks.
An extinction-risk assessment has not been added yet.
The 2012 review identified fire, dieback affecting montane vegetation and climate change as potential threats to known populations. The state Department of Biodiversity, Conservation and Attractions’ December 2025 South Coast regional conservation plan proposes biennial post-fire habitat surveys for this and other assassin spiders. It also specifically calls for surveys on the summits of intervening peaks, especially in unburnt vegetation, to clarify the distribution of Z. robinsi.