Bornella japonica
Baba, 1949

Family: Bornellidae


Known only from Japan


If anyone has photos of a Bornella with only 3 pairs of dorsolateral processes [cerata] then it could possibly be this species. If so, I would love to see them. ... Bill Rudman

I am not sure if this is a distinct species or not. In Baba's description he says it is of similar size and colour to Bornella stellifer [as B. digitata] but that it is easily distinguished by the following characters:
• Rhinophore sheaths with 4 supra-marginal papillae, the hindmost and largest subdivided into 2-3 smaller papillae. [In B. stellifer the supra-marginal papillae are simple].
• Dorso-lateral processes in 3 pairs, [6 pairs in B. stellifer].
• Shape of radular teeth similar in both species but formula of B. japonica is 35 x 14.1.14, and of B. stellifer 32x 7[or 8].1. 7[or 8].

Baba mentions other differences in the shape of the dorso-lateral processes ('cerata') but they are not clear in his illustrations. It is possible a photo in Kieu Suzuki's book [no 195, p 130 - identified as B. digitata] could be this species but I am not sure.

• Baba, K. (1949) Opisthobranchia of Sagami Bay collected by His Majesty, the Emperor of Japan. Iwanami Shoten, Tokyo.

Authorship details
Rudman, W.B., 2001 (September 3) Bornella japonica Baba, 1949. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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