Notobryon clavigerum is a species of sea slug, a nudibranch, a marine gastropod mollusk in the family Scyllaeidae.

[1] The rhinophoral sheaths of Notobryon clavigerum have a crest which is oriented longitudinally running along the posterior margin and the anterior margin.

It terminates distally in a wavy margin.

With the exception of the tip, the edges of the dorsolateral lobes are smooth, stand up recurved, and display claw-like papillae that are small and in a row.

[2] This species is found in the Western Pacific Ocean such as in the waters of Japan.