Known only from Indonesia. Reported here from the Philippines.
Engine Point, NE Sulawesi, Indonesia, 21 June 2001, 5 metres. Approx 25-30 mm long. Photos: J. Anderson.
The body and parapodia are bright blue with a colour pattern of orange and black bands. The parapodia are edged with a broad orange band with a thin black line separating it from the inner blue area. The orange and black margin continue down on to the foot and down each side of the body completely enclosing the blue on the parapodia. The rhinophores are tipped with orange and black and the leading edge of the foot has a similar orange and black edge. There is a thin black line transversing the 'neck' region of the head just behind the base of the rhinophores. It is very similar in colour to Thuridilla undula the main difference being that the parapodial margin is very undulating, the inner border between the orange and black margin and the inner blue region forming a sinuous line.
See Thuridilla coerulea for comparison with the similarly coloured T. undula and T. lineolata.
• Gosliner, T.M. (1995) The genus Thuridilla (Opisthobranchia: Elysiidae) from the tropical Indo-Pacific, with a revision of their phylogeny and systematics of the Elysiidae. Proceedings of the California Academy of Sciences, 49(1): 1-54.
Rudman, W.B., 2001 (August 4) Thuridilla lineolata (Bergh, 1905). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/thurline
January 9, 2009
From: Richard Gilliland
Concerning message #22117:
Thank you for the reply, yes unfortunately even our even though we only do cultured corals they still bring in a lot of hitchhikers - most of them usually "bad" for an aquarium.
email@example.comGilliland, R., 2009 (Jan 9) Re: Thuridilla lineolata from the Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22139
January 8, 2009
From: Richard Gilliland
Concerning message #21408:
I recently received these from shipments that came in with live coral from Jakarta. Anyone know what they eat?
Mine is very small maybe as long as a dime.
Locality: Jakarta, 23 Dec 2008
firstname.lastname@example.orgGilliland, R., 2009 (Jan 8) Re: Thuridilla lineolata from the Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22117
Small invertebrates like this are, I guess, the usually unnoticed 'collateral damage' of the aquarium trade in 'live rock' and live coral. Species of Thuridilla, like all sacoglossan sea slugs, are herbivorous, but I can't be much more specific on their food as we still have much to learn about most species. My guess is that it would feed on filamentous green algae, so there is a chance, with a bit of luck, that it would find an appropriate food source in a 'tropical' aquarium - perhaps an algae which has also hitched a ride from Jakarta. In your photo it seems to be crawling over a piece of living coral. To have any chance of survival it needs to be kept with rock and/or pieces of coral skeleton - no longer with living tissue - on which algae can grow.
April 2, 2008
From: Gary Cobb
Concerning message #20843:
Hi Bill and everyone!
During Sunday's dive at a newly found spot we dubbed Bornella Reef, I came across this unusual colour variation of a very common species here ... Thuridilla splendens. I could be wrong! As you can clearly see there are no blue spots, just bands of colour which match the species we find here.
I have included the in situ photo so you can where it resides.
Locality: Old Woman Island, Mooloolaba, Sunshine Coast, 14 m, Queensland, Australia, Pacific Ocean, 14 October 2007, Subtidal. Length: 24 mm. Photographer: Gary Cobb.
email@example.comCobb, G.C., 2008 (Apr 2) Possible colour variant of Thuridilla splendens?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20966
Thanks for these photos. It raises an interesting point - are T. splendens and T. lineolata extremes of one species, or are we mixing some spotted T. lineolata with T. splendens? I am pretty sure your photos here are of T. lineolata, which make me wonder if earlier photos I have identified as T. splendens are also T. lineolata? [See messages #3108; #15146; #19765] and perhaps even your spotted animals in #20630.
If these animals are very common in your normal diving haunts then it would be valuable to keep an eye out for mating events - not that commonly seen I suspect - or color forms which illustrate a link between the 'lined' animal in this message and the more 'normal' blue spotted animals.
March 18, 2008
From: Bill Byrne
On the species list it says that Thuridilla lineolata is "Known only from Indonesia. Reported here from the Philippines."
Here is further information that it is indeed found in the Philippines - specifically Malapascua.
Locality: Malapascua, 9 M, Philippines, 03 Feb 2008, sandy. Length: 25-30 mm . Photographer: Bill Byrne.
Keep up the good work,
firstname.lastname@example.orgBill Byrne, 2008 (Mar 18) Thuridilla lineolata from the Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21408
Thanks for this. It looks like we now have as many records on the Forum from the Philippines as we have from Indonesia.
March 24, 2004
From: Paul Osmond
Although not far from other sightings on the Forum in the Philippines, this Thuridilla lineolata was photographed on a night dive on Malapascua Island (just across from Cebu, the Philippines) on March 6th, 2004.
It was on the wreck of the 'Lighthouse Barge' in about 4-5 metres of water and was approximately 25-30mm in size.
Malapascua is an incredible nudibranch haven so as I process the images from this trip I will send in any of interest.
email@example.comOsmond, P., 2004 (Mar 24) Thuridilla lineolata from Malapascua Island, Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/12505
Although we have photos from the Philippines of this species, I am still happy to receive more photos, as it is helpful in understanding the extent of colour variability in different species - and it is beautiful.
August 25, 2003
From: Linda Ianniello
Here is a photo of what I believe is a slightly different color variation of Thuridilla lineolata from Indonesia for the forum.
Date: August, 2003
Dive Site: Black Magic at Sangeang Island
Depth: 30 feet
Length: about 1.5 inches
firstname.lastname@example.orgIanniello, L., 2003 (Aug 25) Thuridilla lineolata from Indonesia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10810
May 1, 2002
From: Erwin Köhler
Here is the next one from the Philippines,
Lipayo, divesite "Dauin".
Date: 08 March 2002
Erwin@medslugs.deKöhler, E., 2002 (May 1) Thuridilla lineolata from the Philippines. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6767
August 11, 2001
From: Erwin Köhler
Thuridilla lineolata is pretty common at the Philippines. I met them at Apo and Cebu Island.
Erwin@medslugs.deKöhler, E., 2001 (Aug 11) Re: Thuridilla lineolata from NE Sulawesi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5060
Like many of these animals, we still have a lot to learn. If it has been found in Indonesia and now the Philippines, I suspect it will be only a matter of time before we have reports of it beig found over a wider geographical area.
August 9, 2001
From: Jim Anderson
Dear Dr. Rudman,
The last of tonight's batch.
The two shots of different animals found on Engine Point, NE Sulawesi on 21 June 01 at 5 metres. They were approx 25-30 mm long. We also saw the same sp. on several other dives all of similar size and at 5-8 metres depth.
email@example.comAnderson, J., 2001 (Aug 9) Thuridilla lineolata from NE Sulawesi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4998
This is Thuridilla lineolata.