Dear Ian,
This is an interesting addition. This animal is present known only from northern New Zealand and Sth Korea, suggesting it is either hitching a ride on shipping or we haven't looked very hard in the ocean in between. I have been calling it Tambja cf. verconis because it has some colour similarities to T. verconis which is known from temperate Australia and northern New Zealand. It also has similarities to the NW Pacific species Tambja sagamiana, in fact the yellow and blue is completely reversed in the two species.

It certainly appears to be a distinct species, but as far as I know, it has not been studied anatomically.
Best wishes,
Bill Rudman

Dear Koh,
Thanks for this. I have called it Tambja cf. verconis on the Forum, not because I think it is closely related to T. verconis, but because it looks quite similar. Tambja verconis is a temperate water species from southern Australia and northern new Zealand, while Tambja cf. verconis has a strange disjunct distribution in Sth Korea and nthn New Zealand. Either we have not looked hard enough in the waters in between, or this is an unnatural distribution, perhaps the result of shipping.
Best wishes,
Bill Rudman

Dear Dong Bum,
Thanks for these photos. I agree that they are colour varieties of this species.
Best wishes,
Bill Rudman

Dear Dong Bum,
This is the same animal as we have on the Forum from northern New Zealand as Tambja cf. verconis. It is surprising to have the only two records so far apart.

Is it a form of T. sagamiana? Typical Tambja sagamiana (Baba, 1955) has a blue background and orange-yellow spots ringed in black. It also has a orange-yellow band around the foot with an a thin inner line of black. In your animal the orange and blue colours are in exactly the opposite places. I am not sure how variable Tambja sagamiana is in Japan, but perhaps one of our many friends there can give us some information.
Best wishes,
Bill Rudman

Dear Daphne & Graham,

It is certainly a spectacular animal and at 8 cms must have been quite a sight.

My first thought was I had seen nothing like it, but on reflection it is quite similar to Tambja verconis. There are photos of T. verconis on the Forum from the Poor Knights. If it is a peculiar colour form of T. verconis I must say I have never seen one like it.

Is it a Tambja, Nembrotha or Robastra?
The only sure way I could tell you what genus it belongs to and whether it has any relationship to Tambja verconis would be for me to dissect it and check out its anatomy. Failing that there are a couple of external clues I can use.

If you look at the photo of its head (lower right) you will see a blue 'lappet' or grooved ridge on either side of the head, which I assume is sensory. Similar structures are found in other species of Nembrotha and Tambja while in the genus Robastra, which hunts and eats other nudibranchs, there are a pair of long prominent tentacles flanking the mouth which can be seen in my reply to one of Ross Armstrong's messages about Roboastra luteolineata.

The second clue is the other photo (upper right) which shows the head of your animal in very close proximity to a half-eaten colony of the bluish arborescent bryozoan that Tambja verconis feeds on. I can't guarantee that it was feeding on the bryozoan, but it is a strong possibility that your animal is a species of Tambja. I can't be sure of its relationship to T. verconis without looking at its anatomy. Failing collecting a specimen, I guess I don't need to say that it would be worthwhile keeping an eye out for more specimens, and see if you can find any colour variation.

Glad to see the prints, and if you have any more of other species I would be glad to include them on the Forum.

Best wishes,
Bill Rudman.