Males and females have two large projections on top of the head.
The described male has a bright white patch on each side of the abdomen. The described female lacks these white abdominal patches.
Eriauchenus bourgini has pointed extensions at the bases of its first legs in both sexes. Short spines also occur near the bases of its long jaws. Distinctive shapes are present on the underside of its body as well as on the head and legs.
The 2018 revision compared it closely with the similar Eriauchenus zirafy. Females of the two species were indistinguishable, whereas the small leg-like appendages beside the male mouth provided diagnostic characters. In E. bourgini, a complex structure near the end of this appendage has four long processes; the corresponding structure in E. zirafy has five.
The authors examined six males and three females of the original type material from La Mandraka. They also described male and female specimens collected in Ambohitantely Forest in April 2001. Despite the similar overall head shape, characters useful for identification differ between sexes: a tiny male structure provided a way to distinguish these two species.
An extinction-risk assessment has not been added yet.
Material examined in the 2018 revision came from La Mandraka and Ambohitantely Forest. Maintaining forest habitat and surveying occurrence with identifiable voucher material would improve distribution information for conservation.