Hermadionella nipponicus is a scale worm known from Japan in the north-west Pacific Ocean from the intertidal zone.

[2] Hermadionella nipponicus has up to about 64 segments with 15 pairs of elytra, which bear a fringe of papillae.

The lateral antennae are positioned ventrally on the prostomium, directly beneath the median antenna (almost completely obscured in dorsal view).

The prostomium also bears a pair of acute anterior projections on the anterior margin.

Notochaetae are about as thick as the neurochaetae, and the neurochaetae bear bidentate tips[2][3]