Doto fragilis
(Forbes, 1838)
Order: NUDIBRANCHIA
Suborder: DENDRONOTINA
Family: Dotidae
DISTRIBUTION
North-east Atlantic Ocean from Portugal and Spain to northern Norway and Iceland.
PHOTO
Plompe toren, de Oosterschelde, the Netherlands. PHOTO: Peter van Bragt.
Can reach 34mm in length. One variety, with a dark brown body and paler cerata, feeds on the hydroids, Nemertsia antennina and N. ramosa. Another variety with a transparent white body with brown pigment only on the head, feeds on Halecium muricatum. Has up to 10 pairs of cerata, each with up to 13 concentric circles of pale tubercles. One important character is a white line along each flank from the rhinophore sheath to the tip of the tail (Thompson & Brown, 1984).
Reference:
• Thompson, T.E. & Brown, G.H. (1984) Biology of Opisthobranch Molluscs, Vol 2. Ray Society: London.
Rudman, W.B., 1999 (August 29) Doto fragilis (Forbes, 1838). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/dotofrag
Related messages
Doto fragilis from Massachusetts, USA
August 3, 2007
From: Paul Young
Hi Bill,
We were diving on Halfway Rock, between Gloucester and Boston, MA and saw these Doto fragilis which seem to be more of the one we have seen before .
Locality: Halfway Rock, 35 feet, Massachusetts, USA, Atlantic, 22 July 2007. Length: 1/2 inches. Photo: Paul Young
Paul Young
youngp@hp.com
Young, P, 2007 (Aug 3) Doto fragilis from Massachusetts, USA. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20311
Dear Paul,
Thanks for this nice photo of your northwest Atlantic Doto. I guess it's best to call it Doto fragilis at present, but we should keep in mind Bernard Piction's feelings about this group of species [message #7288 ].
Best wishes,
Bill Rudman
Re: Doto fragilis from Atlantic coast of France
August 11, 2006
From: François Le Méhauté
Concerning message #17326:
Dear Bill,
Thanks for your answer. This nudibranch is very common in Douarnenez Bay (western Brittany, France, Atlantic Ocean). We can especially observe it in about ten to twenty meters of water, always on the same hydroid, but last Sunday (13 August 2006) I saw one of them at thirty meters on the wreck "La Meuse".
Best regards
François Le Méhauté
flemehaute@club.fr
Le Méhauté, F., 2006 (Aug 11) Re: Doto fragilis from Atlantic coast of France. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/17411Dear François,
The evidence is certainly building up that species of Doto have very specialised diets, each species eating only one, or a very few, species of hydroid.
Best wishes,
Bill Rudman
Doto fragilis from Atlantic coast of France
August 10, 2006
From: François Le Méhauté
Hello,
Can you confirm me that this nudibranch is Doto ussi.
Locality: Douarnenez, 18 metres, France, Atlantic Ocean, 11 July 2006. Photographer: Sylvie Thibaut.
Thanks
François
flemehaute@club.fr
Le Méhauté, F., 2006 (Aug 10) Doto fragilis from Atlantic coast of France. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/17326
Dear François,
Doto ussi is a Tropical Indian Ocean and West Pacific species so it is unlikely to be found living on the Atlantic coast of France. I suspect, from the shape and colour of the cerata that this the north Atlantic species Doto fragilis.
Best wishes,
Bill Rudman
Doto fragilis? in Newfoundland
March 23, 2003
From: Paulette Penton
Hello Everyone,
I am a frequent visitor to this site but this is my first message. I was hoping that someone could give me a hand with naming a few of these species that I had collected for my honours. The pictures are horrible because they were taken with a kids intel play microscope. This species, which I have named a Doto was found at my sampling area in Bonne Bay, located in Gros Morne National Park in Newfoundland, Canada. It was found in July 2002 at 46' with Obelia on a rocky bottom with big boulders and a wall covered with coralline algae. The two individuals found were 2mm and 3mm.
Paulette Penton
g84pmp@mun.ca
Dear Paulette,
As you will see from earlier discussions on this page this species has some similarities to the European species Doto fragilis but until the anatomy and biology of this Nth American species is studied and compared with European species there ii no way to be sure they are the same species
Best wishes,
Bill Rudman
Doto species from Massachusetts, USA
January 13, 2003
From: Alan Shepard
Bill -
Nudibranch season is just getting in to high gear here in New England and already I've found a couple of interesting species. This one is a Doto of some sort but I'm not sure which. The only other I've seen up here (sent photo last year) was completely white. This one has a pinkish coloration in the cerata. I suppose it could be the same species with just a different coloration. Maybe you or Bernard Picton can offer an idea as to its identity.
It was very small, maybe 6mm or so. I found it in approximately 6m of water. Water temperature that day was a chilly 40f.
Thanks,
Alan Shepard
alan.chepard@snet.net
Shepard, A., 2003 (Jan 13) Doto species from Massachusetts, USA. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/8882Thanks Alan,
I guess we can only do what Bernard Picton suggested last year when discussing Paul Young's message - tentatively identify it as Doto fragilis or put it in the too hard basket. Anatomically species of this genus can be quite similar, and often the best way to separate them is to identify their food.
Cheers,
Bill Rudman
Doto species from Massachusetts, USA
July 2, 2002
From: Alan Shepard
Dr. Rudman
I've attached a recent photo [April 2002] I took at Folly Cove in Gloucester, Massachusetts, USA. This tiny nudibranch was only 5mm long or so and was in about 5m of water. It was a totally new species for me. I knew it was a Doto species but wasn't sure which one. I sent the photo to Dr. Larry Harris at the University of New Hampshire and he tentatively IDed it as Doto columbiana. It however does not look like the Doto columbiana on your site.
Sincerely,
Alan Shepard
alan.chepard@snet.net
Shepard,A., 2002 (Jul 2) Doto species from Massachusetts, USA. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6917Dear Alan,
Have a look at Bernard Picton's recent comments on photos of this species that Paul Young sent from Massachusetts. He considers that it is probably D. fragilis. The 'cf' in the name of the Doto cf. columbiana on the Forum is to indicate it just looks a bit like D. columbiana but we really aren't sure. In some groups of animals all I can do on the Forum is shine the spotlight on 'problem areas' which woud be worth a closer look. Doto qualifies as such a group almost everywhere on the world.
Cheers,
Bill Rudman
Doto? From Massachusetts
June 20, 2002
From: Paul Young
My wife and I were diving recently at Back Beach in Rockport, Massachusetts [USA]. We found this critter in about 15' of water. It is about 7mm long. The first photo shows the animal better but the second shows the rhinophore sheaths better. We suspect it is a Doto. [Photos by Paul Young].
Paul
young@underwater.org
Young, P. , 2002 (Jun 20) Doto? From Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7288Dear Paul,
This is difficult to identify as it is a Doto with no spots or markings apart from white glandular marks which most species have. I would call it Doto fragilis if I found it here in the Eastern Atlantic. However there is some evidence that Doto fragilis in Europe may be a composite species. Individuals feeding on the Hydroid Nemertesia antennina and Nemertesia ramosa are considered typical in appearance, but smaller individuals with paler coloration are found on Halecium halecinum. Christine Morrow ran some gel-electrophoresis on these two types and there was some evidence that they were genetically isolated - implying that they are distinct species. There is also a form of Doto fragilis which we call the 'giant' form which feeds on Halecium muricatum. Given the strict diet-specificity in other Doto species I suspect that we are looking at three species grouped under the name Doto fragilis here in the NE Atlantic.
I have also sent some photos of the various forms of this species from the British Isles for comparison.
Bernard Picton
bernard.picton.um@nics.gov.uk
Doto fragilis from British Isles
June 20, 2002
From: Bernard Picton
Hi Bill,
To accompany Paul Young's photos of Doto from the eastern USA, here are some pictures of the three forms of Doto fragilis that I recognise from the British Isles.
• Image 1: Strangford Lough, Northern Ireland - June 1976 - 15mm - on Halecium halecinum
• Image 2: Belfast Lough, Northern Ireland - Sept 2001 - 25mm - on Nemertesia antennina
• Image 3: Lundy Island, Bristol Channel, England - July 1976 - 34mm - on Halecium muricatum
Bernard
bernard.picton.um@nics.gov.uk
Thanks Bernard,
Bill Rudman
Doto fragilis from Holland
September 8, 1999
From: Peter H. van Bragt
Dear Bill,
Here is a photo of Doto fragilis to add to the Netherlands' List.
Location: Plompe toren, de Oosterschelde, the Netherlands
With best regards
Peter H. van Bragt
Peter.vanBragt@ftn.hsbrabant.nl
van Bragt, P.H., 1999 (Sep 8) Doto fragilis from Holland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1262Thanks Peter,
Bill Rudman.
