Pleurobranchus weberi
(Bergh, 1905)
Order: NOTASPIDEA
Superfamily: PLEUROBRANCHOIDEA
Family: Pleurobranchidae
DISTRIBUTION
Known only from Indonesia, Philippines.
PHOTO
Malapascua Is., Philippines, divesite "Japanese Cargo Wreck". Depth: 25m. Length: 18-20cm. 23 Feb. 2003. Photo: Erwin Koehler
Large purplish brown pleurobranch with white double rings on the mantle. Mantle with small rounded tubercles. Apart from a record from Mindinao, Philippines on Mike Miller's site [http://slugsite.us/bow/nudwk132.htm], I know of no other published record of this species since its original description from Saleyer Is., S of Celebes, Indonesia (Bergh, 1905). The colour plate [Plate 2, fig 1 - as Oscanius weberi] clearly shows the conspicuous double white rings on the mantle. This species has colour similarities to the dark purple colour form of Pleurobranchus forskali, but in that species if white rings are present, they are single half circles which line the outer edge of each of the mantle tubercles. In P. weberi, the mantle tuberles are much smaller, and the white circles are independent of the tubercles. Like P. forskalii this species apparently grows to quite a large size - at last 20cm.
Reference:
• Bergh, L.S.R. (1905). Die Opisthobranchiata. Siboga Expeditie Report, 50: 248pp., Pls 1-20.
Rudman, W.B., 2003 (April 13) Pleurobranchus weberi (Bergh, 1905). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/pleuwebe
Related messages
Re: Pleurobranchus weberi? from Western Australia
July 19, 2007
From: Erwin Koehler
Concerning message #20130:
Dear Bill,
here is a large shot from my earlier message [#9569] so you can take a more detailed look at the mantle.
Philippines, Malapascua Is., divesite "Japanese Cargo Wreck", near Tapilon Village. Depth: 25 m, 23 Feb. 2003. Size: 18-20 cm (!). Photo: Erwin Koehler
Erwin Koehler
Erwin@Philippine-Sea-Slugs.com
Koehler, E., 2007 (Jul 19) Re: Pleurobranchus weberi? from Western Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20251
Dear Erwin,
Thanks very much for this. I have never seen this species alive so from all the previous photos the white rings appeared to be solid white pigment so I was a bit puzzled by Brad Cox's animal yesterday in which the rings seemed to be caused by small white sand grains stuck around the two rings of the large compound tubercles. From the two close-ups I have posted from your higher resolution photo, it seem the same situation exist with your 'typical' P. weberi from the Philippines. perhaps the tubercles secrete a sticky secretions which captures small white detritus. It is certainly a strange way to build a colour pattern but it seems to show that Brad's animal is indeed P. weberi, which greatly increases is geographic range.
Best wishes,
Bill Rudman
Pleurobranchus weberi? from Western Australia
July 18, 2007
From: Brad Cox
Bill
I have a question regarding Pleurobranchus weberi. I have looked on the forum for a similar looking Nudibranch but have only found Pleurobranchus weberi. You have in the forum they are rare and known only from Indonesia & the Philippines. Is this the case or is this in fact another species.
Brad
Locality: One Mile Jetty Carnarvon, 6-7 meters, Western Australia , Indian Ocean , 02 October 2005, Muddy sandy Bottom. Length: 200mm. Photographer: Damien Preston .
Damien Preston
outbackcoastdive@westnet.com.au
Dear Brad,
Information on any species is only as good as the state of our knowledge, so there is always the chance that you can improve the information on the Forum. That is especially true of geographical distributions.
So I wouldn't be surprised if P. weberi turned up in Western Australia. Your animal certainly looks like P. weberi but its colours are not quite the deep purple and white found in other specimens. However it could be a colour variant. The large compound tubercles in your photo look like those of Pleurobranchus grandis, but I would need to see a higher resolution photo of typical P. weberi to see what its tubercles were like. I can't be 100% sure, but I think we should tentatively consider it to be P. weberi.
Best wishes,
Bill Rudman
Pleurobranchus weberi from The Philippines
May 5, 2005
From: Paul Osmond
Bill,
I have been meaning to send you this image for quite some time.
Two things - firstly a wideangle shot of a sea slug which is rare enough, however more importantly this is Pleurobranchus weberi.
This image was likely taken on the same shipwreck as the image from Erwin Köhler from 2003 [#9569 ], although he doesn't specify the Tapilon as the Japanese Cargo wreck he saw this on (there are two other wrecks at the same depth in the area).
Locality: Wreck of Japanese cargo ship, near Tapilon Village, Malapascua Island, Cebu, The Philippines. Depth: 30 m. Length: 250 mm. 03 March 2004. Ship Wreck. Photographer: Paul T. Osmond
In my notes I have this specimen as almost a foot in length [30 cm].
Enjoy,
Paul
www.deepseaimages.com
marriard@deepseaimages.com
Osmond, Paul T., 2005 (May 5) Pleurobranchus weberi from The Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13707
Dear Paul,
Thanks for these photos. It is great to get more information on such a seldom recorded species.
Best wishes,
Bill Rudman
Pleurobranchus weberi - another sighting
December 11, 2003
From: H.Haluk Akbatur
Dear Bill,
On a recent visit to Indonesia I found three different pleurobranchs but can only identify one - Euselenops luniceps.
[see message 1, message 2]
They were all seen on 18 November 2003, Dive site: Just front in (North-east of Bali, Amlapura, Scuba Seraya Resort,] Size: 15 cm, Depth: 3-15m.
Thanks for any help in identifying them.
H.Haluk Akbatur
Lasergoz@ttnet.net.tr
Akbatur, H.H., 2003 (Dec 11) Pleurobranchus weberi - another sighting. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/11652Dear Haluk,
This is an interesting find. It is Pleurobranchus weberi. As I discuss on the Fact Sheet this rarely found species has only been reported twice since its original description from Indonesia in 1905.
Best wishes
Bill Rudman
Pleurobranchus weberi from the Philippines
April 15, 2003
From: Erwin Köhler
Dear Bill,
Here is a picture of what I think is Pleurobranchus weberi. [At Mike Miller's site
http://slugsite.us/bow/nudwk132.htm a similar looking one is identified as this].
My photo is from the Philippines, Malapascua Is., divesite "Japanese Cargo Wreck".
Size: 18-20cm (!)
Depth: 25m
Date: 23 Feb. 2003
Erwin
Erwin@medslugs.de
Köhler, E., 2003 (Apr 15) Pleurobranchus weberi from the Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9569Thanks Erwin,
This is a very interesting find. Apart from the record you mention on Mike Miller's site [from Mindinao, Philippines], I don't know of a published record of this since its original description from Saleyer Is., S of Celebes, Indonesia (Bergh, 1905). The colour plate [Plate 2, fig 1 - as Oscanius weberi] clearly shows the conspicuous double white rings on the mantle. I have looked at the plate a few times, wondering if it is a colour form of Pleurobranchus forskalii, but in the dark purple form of that species if white rings are present, they are single half circles which line the outer edge of each of the mantle tubercles. In P. weberi, the mantle tuberles are much smaller, and the white circles are independent of the tubercles. Like P. forskalii this species apparently grows to quite a large size.
Best wishes,
Bill Rudman
