In the described male and female, the dark brown abdomen is scattered with lighter round patches.
There are six short spines on top of the head. The carapace, long jaws and legs are reddish brown, with darker rings on the legs.
Female Madagascarchaea legendrei can have larger bodies than males, while the femur of the first leg is similar in length in the measured sexes. Body size and the proportions of an individual leg segment reveal different aspects of their build.
The 2018 revision reported body lengths of 1.46–1.67 millimetres in five males and 1.81–2.02 millimetres in five females. Mean first-leg femur length was 2.32 millimetres in males and 2.29 in females: the larger female body did not translate into a proportionally longer femur.
Relative to carapace length, that segment measured 3.01–3.66 times in males and 2.71–3.05 times in females. These measurements of Ranomafana spiders document differences in leg proportions beyond overall body size.
An extinction-risk assessment has not been added yet.
Madagascar National Parks lists selective logging, bamboo collection and gold mining among pressures on Ranomafana National Park. It reports patrols, ecological monitoring and reforestation through a 2017–2022 project. Repeated surveys of this spider’s montane rainforest localities and dead-foliage microhabitats could clarify its occurrence.