Idionyx rhinoceroides[2] is a species of dragonfly in the family Synthemistidae.

It is known only from a single female collected from type locality (Dhoni, Palakkad, Kerala) in the Western Ghats of India.

Its thorax is metallic emerald-green, coated with yellow hairs on dorsum.

There is a narrow oblique citron-yellow stripe traversing the spiracle and another bordering the lower part of metepimeron.

Beneath the side is yellow, with an oblique bluish-black stripe and a triangular blackish-brown spot.