Re: Onchidoris neapolitana from the Adriatic Sea

May 9, 2006
From: Cristian Magnani

Concerning message #16434:

Dear Bill
In order to get some more information about this Onchidoris, i went back on the shipwreck where we first saw this nudibranch ( in spite the red bryozoan being very common in the area, this shipwreck is the only spot where these Onchidoris are commonly seen...actually i do not know why)

I took some photos of an Onchidoris with its eggs.

Locality: Numana, 10, Italy, Adriatic Sea, 06 May 2006, Shipwreck. Length: 8 mm. Photographer: Cristian Magnani.

Sorry, the quality is not very high but it was an uncomfortable place..
thanks for your help
Best wishes from Italy
Cristian

cristianmagnani@hotmail.com

Magnani C., 2006 (May 9) Re: Onchidoris neapolitana from the Adriatic Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16549

Dear Cristian,
Thanks for these photos. Although we all appreciate perfect photos,  the Forum is not a photo competition, so I am very grateful for any photos, especially of rarely photographed animals like this. And specially when they show interesting biological information. We can see from your photos that this animal prefers to lay its eggs on parts of the bryozoan colony in which the living zooids have been removed. This has led to a bit of overcrowding and laying of one egg spiral over the top of others. I am not sure what that does to the survival prospects of an egg which ends up at the bottom of the pile.

The other interesting thing is that one of your photos - by luckily being a little out of focus - shows the flexible papillae which cover the back of this species quite clearly. These were not so clear in your last message. To those of you who don't do much photography, one of the problems with photographing small animals with long body projections is that as you increase the magnification of your photo, you are able to get less and less of the animal in sharp focus. Even with manual focus it is difficult to judge what to focus on to get a good photo and in 'uncomfortable' places like Cristian was working in, it is often impossible. So you have to decide whether to focus on the body, or the papillae, or the egg ribbons and just hope the rest of the photo is not too blurred.

Thanks again for sharing these photos with us,
Bill Rudman

Rudman, W.B., 2006 (May 9). Comment on Re: Onchidoris neapolitana from the Adriatic Sea by Cristian Magnani. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16549

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