Re: Unknown Onchidoris from Scapa Flow, Scotland

January 12, 2010
From: Bernard Picton

Concerning message #22871:

Hi Bill,

Ian just emailed to alert me to this one. I'm pretty certain that it is Onchidoris inconspicua. In the original description the pale yellow rhinophores, dull white gills and sprinkled brown spots are all mentioned. The illustration shows less spotting than in these individuals, but the nature of the spots is very similar, individually irregular in shape and distributed evenly but randomly. Some indication of spots on the tips of tubercles is apparent in the drawing. The underside is illustrated with a large dark patch of 'liver' and the description says "the liver appears in a large, broad patch of dark purple through the centre" exactly as shown in Ian's photograph of the underside. As far as I am aware this species has not been reliably reported since its original description except for a record by Chris Todd in his PhD study at Robin Hood's Bay, Yorkshire, North Sea. Thompson also gives records for the Irish Sea, Gullmarfjord and Arcachon, but as there are several very similar species it is difficult to be certain of these.

Congratulations to Ian on (if I'm right) getting the first colour photographs of this elusive species.

Bernard Picton

bernard.picton@nmni.com

Picton, B.E., 2010 (Jan 12) Re: Unknown Onchidoris from Scapa Flow, Scotland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23075

Dear Bernard,

Thanks for the input. I assume it's a bit cold for fieldwork in your part of the world at present. Down here in Sydney it is 42 deg C today!

Best wishes,
Bill Rudman

Rudman, W.B., 2010 (Jan 12). Comment on Re: Unknown Onchidoris from Scapa Flow, Scotland by Bernard Picton. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/23075