Living males and females have lime-green abdominal markings.
In the described male and female, the abdomen has a single hump on its back. The head has four projections, each tipped with a short spine.
Eriauchenus ranavalona has long chelicerae in front of its elevated, neck-like head region. The male described in 2018 had chelicerae 3.28 mm long, with a spine 0.42 mm from the base. The described female had chelicerae 2.62 mm long and a spine 0.48 mm from the base.
The male holotype and female paratype came from different collecting sites within Ranomafana National Park: Vohiparara in 1998 and the Vatoharanana River area in 2003. Microscopic measurements and illustrations documented the elevated head region and chelicerae. The study combined observations of living specimens with detailed preserved morphology to distinguish similar spiders, drawing on collections made in different years.
An extinction-risk assessment has not been added yet.
Around Ranomafana National Park, Centre ValBio undertakes forest restoration. Its 2023 annual report records 10,487 seedlings produced in its campus nursery, of which 1,734 were planted by a tour-guides’ association, staff and a local primary school. A separate programme around fragmented forests combines native trees with income-generating crops. These are regional efforts linking livelihoods and forest recovery.