Re: Onchidoris depressa from Ratnagiri, India

April 16, 2010
From: Bernard Picton

Concerning message #22988:

Hi Bill,

I collected two Onchidoris depressa yesterday to compare with your records from India and the Pacific. I think they have some significant differences, but it would be interesting to try and get some DNA sequence data to compare. You will see from the attached photograph that Irish animals have much thinner tubercles than the Indian and Pacific specimens. Also the body shape seems more elongated and the markings are in longitudinal lines. Clearly they are camouflaging themselves on bryozoa, so the pattern and marks with central darker spots are designed (by evolution) to match the zooids of the bryozoan, a good example of convergence.

Locality: Murles Point, Mountcharles, Co Donegal., Low tide mark, shore., Ireland, Atlantic Ocean, 15 February, 2010, Intertidal. Length: 10mm. Photographer: Bernard Picton.

Bernard Picton

Bernard.Picton@nmni.com

Picton, B.E., 2010 (Apr 16) Re: Onchidoris depressa from Ratnagiri, India. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23240

Dear Bernard,

I agree that if all these animals are the same species then they have a remarkable ability to disperse and survive different temperatures. To my untutored eye the animals I first found animals in Tasmania look remarkably like your photos and their radular morphology is almost indentical.

As you suggest, it seems to be a case for DNA

Best wishes,
Bill Rudman

Rudman, W.B., 2010 (Apr 16). Comment on Re: Onchidoris depressa from Ratnagiri, India by Bernard Picton. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23240

Factsheet

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