Chelidonura flavolobata
Heller & Thompson 1983
Order: CEPHALASPIDEA
Superfamily: PHILINOIDEA
Family: Aglajidae
DISTRIBUTION
Red Sea
PHOTO
UPPER: Jeddah, Saudi Arabia (Red Sea) PHOTO: Gordon T. Smith
LOWER: Hurghada, Red Sea, divesite "Fort Arabesque Shore", approx 5cm long, depth 10m, 1 February 1999. Photo: Franco de Lorenzi.
Chelidonura flavolobata has only been reported from the Red Sea. It is black, but often appears deep blue, probably from the light effects caused by the dense covering of cilia. It has been considered unique from other species of Chelidonura in having a large yellowish lobe on each side of the mouth, but see discussion suggesting that is quite variable in colour, with some specimens having white head lobes with the yellow limited to a marginal band, and having a white edge to parts of the parapodia and the posterior tip of the head shield. It grows to about 5 cm.
References:
• Heller & Thompson, T.E. 1983 Opisthobranch molluscs of the Sudanese Red Sea. Zoological Journal of the Linnean Society, 78(4): 317-348
• Yonow, N. 1990 Red Sea Opisthobranchia: The orders Sacoglossa, Cephalaspidea, and Nudibranchia: Doridacea (Mollusca, Opisthobranchia). Fauna of Saudi Arabia, 11: 286-299
Rudman, W.B., 2001 (January 21) Chelidonura flavolobata Heller & Thompson 1983 . [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/chelflav
Related messages
Eggs of Chelidonura flavolabata
March 29, 2007
From: Lior Harari
Dear Bill,
I took the pictures of these two Chelidonura flavolobata at the same spot, both on the same small piece of coral.
Only when I looked at the pictures at home I realized that the second one has a small pile of eggs next to it.
Locality: Princess beach, Eilat, 20 meters, Israel, Red Sea, 16 March 2007. Photographer: Lior Harari.
Lior Harari
hararilior@yahoo.com
Harari, Lior, 2007 (Mar 29) Eggs of Chelidonura flavolabata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19749
Dear Lior,
Thanks for this. For those looking for the second animal that Lior has mentioned, it is only present in the second and third photos and is hidden between the 'tails' of the larger anterior animal. I presume this second animal is mating [as the male], because in aglajids the penis is on the right side of the head, and the female genital opening is in the reduced mantle cavity, which is at the back of the body, just in front of the V formed by the 'tails'.
I am pretty sure the eggs are present in both the lower photos, the bottom photo is 'upside down' in comparison with the middle photo, so the egg mass is just above, rather than just below, the animals. It is the type of egg mass produced by Chelidonura, but I can't say if these animals are the parents.
Best wishes,
Bill Rudman
Chelidonura flavolobata from the Red Sea
May 17, 2006
From: Kamal El Tawil
Hi Bill,
Another case of a white lobed Chelidonura flavolobota: In bottom photo there is a pair of animals a few inches apart; one with a white lobe and the other with a yellow lobe. I have taken several pictures of the animal moving slowly on the reef wall and living coral (msg #13357) where there is no sandy bottom.
Locality: Elphinstone Reef, Marsa Alam, 15 meters, Egypt, Red Sea, 02 May 2006, Deep reef wall. Length: 4 cms. Photographer: Kamal El Tawil.
best regards,
Kamal
kamal@coralworld.net
El Tawil, K., 2006 (May 17) Chelidonura flavolobata from the Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16556
Dear Kamal,
Thanks for the shot of the two animals with different coloured lobes. What is quite inyersting about your photos is the animals crawling over live coral colonies. It was photos like this of C. inornata and C. electra in the Indo-West Pacific crawling over large coral colonies that gave rise to the story that Chelidonura ate corals or at least coral mucus - a myth that appeared in a number of colour picture books on coral reefs. We now know that many species feed on small flatworms so it is possible their attraction to coral colonies is because of the presence sometimes, of swarms of flatworms on corals.
Best wishes,
Bill Rudman
Chelidonura flavolobata - extreme close up
March 9, 2006
From: Oren Lederman
Hi Bill,
I took these pictures of the head of Chelidonura flavolobata last weekend and thought you might find it interesting.
Locality: "Princess Beach", Eilat bay, ~15 meters, Israel, Red Sea, 05 March 2006, Coral head. Length: ~4cm. Photographer: Oren Lederman.
Oren Lederman
lederman@bigmail.co.il
Lederman, O., 2006 (Mar 9) Chelidonura flavolobata - extreme close up. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16039
Dear Oren,
Thanks for these wonderful views of the head of Chelidonura. The sensory bristles on raised fleshy pads on either side of the mouth are unique to this family and seem to have arisen from compound cilia. They are developed to the greatest degree in species of Chelidonura. There are huge nerves from them running back to the cerebral ganglia, emphasising their important role in providing information from the chemical traces left in mucous trails by potential prey animals.
Best wishes,
Bill Rudman
Re: Chelidonura flavolobata - color variation
March 19, 2005
From: Oren Lederman
Hi Bill,
In the last month or two I've been seeing lots of these nudis. and I mean lots (i actually stopped taking photos of them...). Next time I dive in the red sea will be in a month or so, but if there's something in particular that you wish to try and find out about them let me know and i'll pass it to the other members of the local seaslug forum :-)
I'm also sending you a few more photos of this nudi with a light-brown body.
Also, i'm pretty sure i once took a photo of a black-body-completely-white-lobes Chelidonura flavolobata. i'll try and look it up.
Locality: "Dekel" beach, Israel, Red Sea. Depth: ~20 m. 29 Sep 2004. sandy. Photographer: Oren Lederman
Oren
lederman@bigmail.co.il
Dear Oren,
I'm glad I encouraged you to send a few more photos. If you look at the close-up of the head alongside you may be able to see a faint black line along the edge of part of the right yellow lobe. If you have a look at Harro Quitzau's earlier photo of a black form [#10244], this black line is very clear. It's a pretty good link between the brown and black colour forms. If you are going Chelidonura 'hunting' soon it would certainly be worth seeing if you can get the two colour forms to mate with each other, and perhaps you could see if there is any correlation with the background colour of the environment in which they are found. The brown ones seem, from the photos, to be on white coral sand, while the black ones seem to be associated with patches of live coral. I know it would need statistical tests to get a scientifically sound answer, but it would be interesting to see if you and your 'local seaslug forum' can notice anything. Of course I am always waiting for records of these animals feeding. All indications suggest species of Chelidonura feed on flatworms, but a few more actual sightings wouldn't go astray.
One other interesting point I noticed in one of your photos [lower right in your message] are the sensory bristles these animals use to search for their prey. They apparently sense chemicals in the mucus trails of their prey. They can be clearly seen along the front edge of the head.
Best wishes,
Bill Rudman
Black Chelidonura flavolobata with white lobes
March 19, 2005
From: Oren Lederman
Hi Bill,
Took me a while, but I found the pictures of the black Chelidonura flavolobata with white lobes. The lobes in this speciman were white rather than yellow.
Locality: "The University", Eilat, Israel, Red Sea. Depth: ~15 m. Length: ~3-4 cm. April 2004. corals. Photographer: Oren Lederman
Oren
lederman@bigmail.co.il
Dear Oren,
Thanks for these photos. They add to a couple of points I made in reply to your last message [#13356]. Firstly your two lower photos show the black line along the yellow lobes that I mentioned, and secondly, these black animals were found on living coral outcrops, rather than in sand, which seems to be where you find the light brown form. It looks like the black ones can have white or yellow lobes.
Best wishes,
Bill Rudman
Chelidonura flavolobata - color variation
March 17, 2005
From: Oren Lederman
Hi Bill,
Since you showed interest in Chelidonura flavolobata, I'm sending a few more photos from last weekend. That's the second time I have seen this color variation.
Locality: "The Caves", Eilat Bay, Israel, Red Sea. Depth: ~18 m. Length: ~4 cm. 12 Feb 2005. on a coral. Photographer: Oren Lederman.
Oren
lederman@bigmail.co.il
Lederman, O., 2005 (Mar 17) Chelidonura flavolobata - color variation. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13330
Thanks Oren,
It's certainly interesting to see this colour form. It seems this species is either black with solid orange-yellow lobes or a lighter brown with a white line on the yellow lobes. These animals look very like some in one of Nils Anthes' messages [#10033]. As we know very little about this species, photos such as yours showing these variants help us build up a better picture of ther species.
Best wishes,
Bill Rudman
Chelidonura flavolobata from the Red Sea
March 9, 2005
From: Oren Lederman
Hi Bill,
Here are some photos of Chelidonura flavolobata . They seem to be quite common this time of the year.
Upper & lower right: - "The lighthouse -south" at about ~20 m depth. (Red Sea, Eilat, Israel). Length - ~5-6 cm.
Lower left: - "The princess beach", at about ~20 m depth. (Red Sea, Eilat, Israel). Length - 1cm.
Photographer: Oren Lederman
Oren.
lederman@bigmail.co.il
Thanks Oren,
It's interesting to see the colour variation.
Best wishes,
Bill Rudman
Chelidonura flavolobata from Egyptian Red Sea
January 4, 2005
From: Michael Mrutzek
Hello Bill
Here is a photot of Chelidonura flavolobata for your Forum
Locality: Reef at Hurghada, Egypt, Red Sea. Depth: 10 meters, Length: 30 mm. June 2004. Photographer: M. Mrutzek
Michael Mrutzek
Michael@meeresaquaristik.de
Mrutzek, M., 2005 (Jan 4) Chelidonura flavolobata from Egyptian Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/12877Thanks Michael,
Bill Rudman
Chelidonura flavolobata from the Red Sea
July 2, 2003
From: Harro H. Quitzau
Hello Bill,
I found this Chelidonura flavolobata in the Red Sea
Egypt - Red Sea / Safaga
Dive Site: Shaab Saiman at 20m
30 May 2003
Best regards,
Harro
Harro@Quitzau.info
Dear Harro,
Thanks for these photos. I have included enlargements of the head as it will help in our comparisons with similarly coloured species. In the photo alongside there appears to be a distinct black groove along the anterior edge of the yellow lobes. I presume this is the site of the sensory bristles which all species of Chelidonura have. It certainly looks different from the yellow-orange band found in 'typical' Chelidonura inornata.
Best wishes,
Bill Rudman
Chelidonura flavolobata from Red Sea [2]
May 31, 2003
From: Nils Anthes
Hi Bill,
In answer to your comments. Yes, we had a marine biological course with 15 students there, but also intended to collect more data on mating behaviour in Aglajids. Again, we were quite lucky: We found C. flavolobata and C. livida in reasonable numbers (> 10), and C. sandrana/tsurugensis very abundant(> 100 ind in a small bay). For all three species we collected quite nice data on mating behaviour and also observations on genital structure (penial papilla) "in action". Having now seen a number of mating Chelidonura species it is very obvious that not only penial structure but also mating behaviour is quite diverse even within this closely related group. [Red Sea aprox 20 km south of "Quseir"].
Kind regards
Nils
anthes@uni-muenster.de
Anthes, N., 2003 (May 31) Chelidonura flavolobata from Red Sea [2]. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10080Thanks Nils,
You are obviously having a lot of luck in chasing aglajids - or should I say you have beome very skilful at finding them. I have been having second thoughts on the photos you sent and wonder if rather than being C. flavolobata they are an Indian Ocean colour form of C. inornata?
Best wishes,
Bill Rudman
Chelidonura flavolobata & C. inornata
May 31, 2003
From: Bill Rudman
PHOTOS: Upper: 'Spotted' form of C. flavolobata. Red Sea ca. 20 km south of "Quseir", May 2003. Photo: Nils Anthes. Lower: C. inornata. Christmas Island, Line Islands, eastern Kiribati, 35mm long. May 2003. Photo: Don Barclay.
Nils Anthes recent messages [message 1, message 2, message 3] raise the question of just what is the relationship between C. flavolobata from the Indian Ocean and C. inornata from the Western Pacific. Also, is Chelidonura sp. 4 from Fiji a colour variant of C. inornata?
C. flavolobata, known previously from only 2 specimens, was originally characterised by the solid yellow lobes on either side of the head and the lack of white spots anywhere. Nils's observations suggest that C. flavolobata can vary quite significantly in colour from animals which are pure black with yellow head lobes, to animals in which the yellow is restricted to a marginal band on white head lobes and with 'dense white spots around the eyes, at the edges of the parapodia and the rear end of the head shield'. In the upper photo which shows one of these 'spotted' animals, there also appears to be a white band across the front of the head. A similar band is found in C. inornata.
Looking at the messages of other animals identified as C. flavolobata, I am sure that Marina Poddubetskaia's March 2003 photo has the same colour pattern, but I can't see the head clearly enough in her earlier messages [photo 1, photo 2] to be sure.
How can we interpret this? From Nils' mating observations it would seem that C. flavolobata is much more variable in colour than earlier reports would suggest. If we compare the colour of this 'spotted' form to the colour of Chelidonura inornata then the only differences are that C. inornata has white spots on the parapodia and foot and usually the white band across the head is more prominent. The similarities though, including the orange band on the head lobes and the position of the white pigmentation on the parapodial borders is quite remarkable.
I would agree that it is probably best to consider the Pacific species and the Indian Ocean species to be separate, but we will need to enlarge the definition of C. flavolobata. However I don't know what to do with Chelidonura sp. 4, from Fiji, which seems to be a C. inornata without white specks on the parapodia, which would make it identical to the white spotted C. flavolobata from the Red Sea.
Bill Rudman
Chelidonura flavolobata from Red Sea [3]
May 31, 2003
From: Nils Anthes
Dear Bill,
Thanks for your response about the identity of our spotted Chelidonura sp: we don't believe it is C. inornata, although like you, we thought it might be. The main reasons are:
• we have seen intermediates between all dark 'typical' C. flavolobata and the spotted ones. I include a picture of one that has some white spots in the eye region, and also few at the rear end of the head shield (not visible on the picture).
• C. flavolobata and the spotted forms also mated with each other (which would of course not be very surprising also between C. inornata and C. flavolobata - especially under lab conditions, as their mating behaviour appears to be very similar)
- At least the C. inornata that we have seen on Heron and Lizard Island all
had much more elongated, slender, pointed "tails", while the posterior lobes
are very broad and round-tipped in C. flavolobata and the spotted forms. This
also applies to all pictures of C. inornata on the Forum.
But anyway - the two species have a lot in common...
Best wishes!
Nils
anthes@uni-muenster.de
Anthes, N., 2003 (May 31) Chelidonura flavolobata from Red Sea [3]. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10123Thanks Nils,
It's certainly an interesting situation. If they are mating together it would suggest they are the same species, but of course it wouldn't rule out the possibility that this population is an Indian Ocean variant of C. inornata or at least a closely related - perhaps a sibling species. I have put my thoughts into a separate message.
Best wishes,
Bill Rudman
Chelidonura flavolobata from Red Sea [1]
May 28, 2003
From: Nils Anthes
Dear Julian and Bill,
The pictures of Julian's Chelidonura from Fiji very much remind me of 3 relatively small (but mature) individuals of Chelidonura flavolobata that we found recently (early May 2003) at the Red Sea ca. 20 km south of "Quseir".
They all had dense white spots around the eyes, at the edges of the parapods and the rear end of the head shield. This gives a very similar pattern. Maybe C. flavolobata is much more widely distributed than previously known?
Nils Anthes
anthes@uni-muenster.de
Anthes, N., 2003 (May 28) Chelidonura flavolobata from Red Sea [1]. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10033Dear Nils,
The Forum has been the source of quite a few major increases in distribution. It's possible we have another one here. It would be nice to get a closer view of the head of the Fijian animal. Was your visit to the Red Sea also for your behaviour work?
Best wishes,
Bill Rudman
Chelidonura flavolobata from Egypt
March 12, 2003
From: Marina Poddubetskaia
Dear Bill,
I found this Chelidonura flavolobata during a night dive in Safaga, Egypt.
Date: February 08, 2003
Location: Safaga, Egypt, Red Sea
Site: Tobia IV
Depth: 12m
Size: 45-50mm
Photos: Marina Poddubetskaia - Nembro website
Best wishes,
Marina.
nembro@nembro.info
Poddubetskaia, M., 2003 (Mar 12) Chelidonura flavolobata from Egypt. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9265Thanks Marina,
This species is a good example of how contributors to the Forum are giving us a better understanding of these animals. Until a couple of years ago this species was known from only two records in scientific papers. From messages to the Forum, it seems that far from being rare, this species is quite common in the Red Sea.
Best wishes
Bill Rudman
Re: Chelidonura flavolobata from Red Sea
April 21, 2002
From: Marina Poddubetskaia
Dear Bill,
Thank you for these confirmations of Chelidonura. I just forgot to tell you about something else on C. flavolobata during this stay in the Red Sea.
One day I was photographing a C. flavolobata and suddenly I made a lot of movement and the animal came off. But, surprisingly it stayed near the rocks attached to corals by a white substance seen on the joined photo. It reminded me of a spider's web - when spiders fall down they always make a line to stay attached. Is it just a coincidence or can C. flavolobata make a substance to attach itself to rocks ?
Best wishes
Marina.
marina.poddubetskaia@francetelecom.com
Poddubetskaia, Marina. , 2002 (Apr 21) Re: Chelidonura flavolobata from Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6763Dear Marina,
Have a look at the page on How slugs crawl. Most snails and slugs have glands which produce a mucous layer on which the foot glides along by muscular waves. In some cephalaspideans, like Chelidonura and other aglajids, the body, including the foot is covered by a heavy layer of cilia, and there is no muscular sole to the foot. In these animals a set of glands at the front of the body produce a layer of mucus which the cilia pushes around the body so the animal actually crawls along in a tube of mucus. This is useful when they crawl through sand and soft sediments, and also, as you have observed, when they fall loose on hard substrates. They also can sometimes be seen 'abseiling' down from one ledge to another by using this mucus tube - so comparing them to spiders is an excellent comparison.
It is intersting to see that in your photo the animal is crawling across a coral colony. Popular books often have photos of Chelidonura crawling over corals, and often the caption says they are feeding on coral mucus. This is quite wrong. We now know that they feed on small flatworms which often occur in large numbers on coral and soft coral colonies.
Best wishes,
Bill Rudman
Chelidonura flavolobata from Red Sea
April 16, 2002
From: Marina Poddubetskaia
Dear Bill,
At the end of March I spent a week in Egypt. It was a dive cruise at the North of Red Sea, between Hurghada and Sinai mountains. All the joined photos come from there.
Could you confirm this is Chelidonura flavolobata please?
Data: about 4cm long, 20 March 2002, "Chebna" / North Red Sea,
5m depth, I saw this cephalaspidean at many dive sites, between 5 and 20m.
Thank you for your help.
Best wishes,
Marina
marina.poddubetskaia@francetelecom.com
Poddubetskaia, Marina. , 2002 (Apr 16) Chelidonura flavolobata from Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6716Dear Marina,
Yes this is Chelidonura flavolobata. These very black anmals are very difficult to photograph.
Best wishes,
Bill Rudman
Chelidonura flavolobata from Saudi Arabia
January 30, 2001
From: Gordon T. Smith
Dear Bill,
Here is Chelidonura flavolobata from the creek north of Jeddah, Saudi Arabia (Red Sea). I had this filed under flatworms until 2 years ago, about 3cm long at 5 metres
Regards
Gordon
aquashot@emirates.net.ae
Smith, G.T., 2001 (Jan 30) Chelidonura flavolobata from Saudi Arabia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3640Thanks Gordon,
Nice to have a photo which shows off the yellow lobes
Bill Rudman
Chelidonura flavolobata from Red Sea
January 22, 2001
From: Erwin Koehler
Dear Bill,
this one is from the Red Sea, Hurghada, divesite "Fort Arabesque Shore".
Size about 5cm, depth 10m, date Feb. 01, 1999. It was taken by Franco de
Lorenzi [cratena@libero.it]
Erwin
Medslugs.Koehler@t-online.de
Koehler, E., 2001 (Jan 22) Chelidonura flavolobata from Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3590Dear Erwin & Franco,
This is quite an interesting find. It is a species of Chelidonura, Chelidonura flavolobata which has only been reported a couple of times before. The yellow lobe on each side of its mouth is its most characteristic feature.
Best wishes,
Bill Rudman
