Juvenile Goniodoris felis from Japan

July 2, 2008
From: Ayumi Murakami


Concerning message #13112:

Dear Bill
I have observed some animals that look like Goniodoris felis. Also there were a lot of smaller animals around them.

My pictures are approx 12 mm wide. I guess from it, the smaller animals are under 1 mm,  nearer 0.5 mm. The bigger animals are 2-2.5 mm. In the middle picture, taken one week after the lower one, at the same place, the animals are a little bigger.

Locality: Izu Peninsula, 6 m, Japan, Pacific Ocean, 11, 17 May 2008, on the buoy on sand. Length: 2 mm and under 1 mm. Photographer: Ayumi Murakami.

I guess they live with the group until they are bigger, because at around 2-4 mm each can survive independent of the group in a slightly different environment, for example on seaweed. They were on a buoy under 6 m of water. It was with a lot of  sponge, hydroids, bryozoans and seaweed.

Do you think that they are parents and offspring? or just gathering to feed?

Best Regards
Ayumi Murakami

umiushi2@masea.info

Ayumi Murakami, 2008 (Jul 2) Juvenile Goniodoris felis from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21664

Dear Ayumi,

Thanks for these interesting photos. We still have much to learn about the early life history of most nudibranchs. I am not sure if Goniodoris felis has a free-swimming veliger larval stage or whether it is direct developer in which small crawling young hatch out of the egg mass.

The tight clustering of the juveniles in your photos would suggest to me that these juveniles are direct developers which have recently hatched out of an egg mass which was attached nearby. One problem with that idea is that we have messages from Dong Bum Koh's [see #12932] showing possible egg masses of G. felis, but the eggs look a bit small for direct developers.  It's possible your juveniles are a cluster of recently settled planktonic larvae which have been attracted to a colonial bryozoan, which presumably is the food of Goniodoris. Basically we will need to confirm the type of egg ribbon this species produces, and confirm what type of development its larva have.

As to whether these are parents and babies. Even the large ones are quite small so I would suspect that these are all juveniles, with the larger ones a few weeks older than the smaller ones.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Jul 2). Comment on Juvenile Goniodoris felis from Japan by Ayumi Murakami. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21664

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