Bijoaraneus postilena

The female has a body length of approximately 5.1 mm, while males are smaller at about 3.6 mm. The cephalothorax is about 2.0 mm long and 1.7 mm wide in females, and 1.8 mm long and 1.45 mm wide in males.^[3]

In life, the spider displays striking coloration with a greenish orange cephalothorax and legs that show weak banding patterns. The opisthosoma is whitish green dorsally with distinctive black markings, while the ventral surface is green.^[3] This coloration likely provides camouflage when the spider rests among foliage.

The female can be distinguished from related species by the inverted triangular shape of the epigynal scape when viewed ventrally. Males are characterized by a sideways-protruding median apophysis on the palpal bulb, which differs from the shorter, non-protruding apophyses of closely related species.^[3]

B. postilena constructs a distinctive web behavior described by early observers. The spider builds a perpendicular snare approximately 3 in (76 mm) in diameter with a free segment and a trap line leading to a nest constructed in a twisted leaf about 1.5 in (38 mm) long, which is bound together with silk. The spider typically sits in the nest with its back facing downwards, holding onto the threads of the web structure.^[4]