Re: More Japanese sacoglossans

June 21, 2002
From: Kathe R. Jensen

Dear Cynthia & Bill,
The photos are of a species of Aplysiopsis, and my guess is that it is A. toyamana (Baba, 1959) or A. orientalis (Baba, 1949) - both originally described as Hermaeina. On the lower photo you can see the branched vessels on the inner surface of the cerata. Also, some cerata seem to have dark tips, which has been described in both species. The median pigmented band on the head has also been described for these two species - brown in A. orientalis and black in A. toyamana. Supposedly the branching vessels on the cerata of A. toyamana are more indistinct and less ramified than in A. orientalis, but this I cannot really distinguish on the photos. The rolled rhinophores have the typical aspect of one flap being shorter than the other.

Jensen, K.R., 2002 (Jun 21) Re: More Japanese sacoglossans. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Kathe,
Having looked at the two descriptions I can see your dilemma. What we don't know is whether the brown in the painting of A. orientalis and in Baba's description, is variable within the species. Some browns in opisthobranchs seem interchangeable with black. Since we don't know I guess the safest course is to identify this animal with Aplysiopsis toyamana (Baba, 1959), with which it fits quite well. Clearly this is another sacoglossan species which needs more sampling.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jun 21). Comment on Re: More Japanese sacoglossans by Kathe R. Jensen. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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