Chromodoris petechialis
(Gould, 1852)
Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae
DISTRIBUTION
Known only from Hawaii
PHOTO
UPPER: Two animals from Hawaii probably Kaneohe Bay, Oahu Id. Photo courtesy of the National Geographic Society. Photographer: Paul A Zahl, Copyright: National Geographic Magazine.
LOWER: Black & white photocopy of Pl.22, figs 391, 391a, from Gould 1856.
Known only from the original description, the original specimens are apparently lost. A photo by Paul Zahl (1959) from Hawaii fits the original description well. It is characterised by the creamy straw-coloured background, the orange border to the mantle and the foot and the irregularly shaped red spots on the mantle. The gills are white with red edging and the rhinophore clubs are bright orange. Kay & Young (1969) identified a species as C. petechialis but as I discuss earlier (Rudman, 1983) their animal is Chromodoris tinctoria. Another red-spotted chromdorid from Hawaii, Hypselodoris paulinae has been recently described. Its shape and detailed colour is quite different from that of C. petechialis.
Is this species now extinct? Any photos or sightings would be very welcome.
ORIGINAL DESCRIPTION:
Doris petechialis (Gould)
Animal rounded-oval, depressed, pale, a little slate-coloured each side, and with a marginal orange-coloured line, and a submarginal lemon-coloured shading; over the whole surface are small, regularly disposed, rose-red blotches, like a petechiae. Cervical tentacles tapering, vermilion-coloured, with only a minute portion laminated. Branchial star of six narrow, tapering, pinnate plumules. Head very small; labial tentacles short, conical; foot narrow, shorter than the body; beneath colourless, the mantle and foot bordered with pale orange.
Length two and a half inches; breadth an inch and a quarter.
Obtained at Honolulu, Oahu, Sandwich Islands. The drawing of the species is somewhat imperfect; yet its characters are sufficiently obvious for its identification. Figures 391, 391 a, dorsal and ventral views of the animal.
References.
• Gould, A.A. (1852) United States Exploring Expedition during the years 1838-1842. Under the command of Charles Wilkes, U.S.N. Vol 12. Mollusca and Shells. 510pp, with Atlas of Plates, 1856. [296-7, Pl.22, figs 391,391a].
• Kay, E.A. & Young, D.K. (1969): The Doridacea (Opisthobranchia: Mollusca) of the Hawaiian Islands. Pacific Science, 23(2): 172-231.
• Rudman, W.B. (1983) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris splendida, C. aspersa and Hypselodoris placida colour groups. Zoological Journal of the Linnean Society, 78: 105-173.
• Zahl, P.A. (1959) Unsung beauties of Hawaii's Coral Reefs. National Geographic Magazine, 116(4) October: 510-525
NOTE: Messages with photos of other species which have been misidentified as C. petechialis have been attached to the appropriate pages. To find these go to the SEARCH page and search for petechialis.
Authorship detailsRudman, W.B., 2001 (March 28) Chromodoris petechialis (Gould, 1852). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/chropete
Related messages
More hope for Chromodoris petechialis
January 22, 2002
From: John Hoover
Bill,
After I sent my earlier message about the "extinct" Chromodoris petechialis I remembered the case of the little cowry Cypraea semiplota, another Hawaiian endemic. It was one of the most common Hawaiian shallow-water cowries during the first several decades of the 20th century. In the 1940s and 1950s, however, the population dwindled and disappeared. No one knew why and some considered it extinct. It eventually returned in small numbers in specific locations and its population bloomed and fell several times. Maybe the beautiful red-spotted C. petechialis will likewise return.
Cheers,
John
hoover@hml.org
Hoover, J., 2002 (Jan 22) More hope for Chromodoris petechialis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6064Thanks John,
It's easier to imagine a collectable shell being collected to extinction than a slug. Many sponges do seem to come and go with great irregularity so I guess there is always a chance that C. petechialis will return - as long as it didn't lose all contact with its favourite food.
Cheers,
Bill Rudman
Chromodoris petechialis still missing
January 21, 2002
From: John Hoover
Hi Bill,
In your reply you ask if any new information about Chromodoris petechialis has turned up. You can be sure that if I seen or hear anything more of these slugs you'll be the first to be notified.
In an earlier message, Scott Johnson suggested that they might live primarily in deep water -- an interesting idea. Related is the possibility that their population center lies in the uninhabited Northwest Hawaiian Islands. Animals found in deep water around the main Hawaiian Islands often occur shallower in the northwestern chain because the water there is cooler.
Unfortunately, almost no diving or collecting takes place in the Northwest Hawaiian Islands except around Midway Atoll. Midway has been surveyed for opisthobranchs several times, but suppose these particular slugs are nocturnal? That would greatly lower the chance of finding them because the northwest islands, especially Midway, are prime tiger shark territory. I'll bet NO ONE goes out diving or snorkeling there at night!
Another possibility is that C. petechialis was endemic to Kaneohe Bay and perhaps Pearl Harbor, both on Oahu. Believe it or not, these two are the only extensive, well-protected, lagoon-like bodies of water in the main Hawaiian Islands. Perhaps C. petechialis fed only on a sponge inhabiting Kaneohe and Pearl -- both these bodies of water appear to have a greater concentration on variety of sponges than most Hawaiian habitats. Since Gould's and even Zahl's day both have had their ecologies greatly disrupted. Among other things, exotic sponges from all over the world have been introduced by shipping. It's not inconceivable, therefore, that some native sponges preyed upon by C. petechialis were displaced and driven extinct by introduced sponges. And with them might have gone the beautiful red-spotted slug.
Since that's a depressing thought, let's hope the first scenario is the correct one! There is still much to be learned about the Northwest Hawaiian Islands.
Cheers,
John.
hoover@hml.org
Hoover, J., 2002 (Jan 21) Chromodoris petechialis still missing. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6049Thanks John,
My thoughts were that Zahl probably photographed animals from Kaneohe Bay which was the focus of his article. I'm afraid the published photo in National Geographic Magazine seems to show green filamentous algae in the background behind the anchor chain which would suggest pretty shallow water. I guess we can only just keep our fingers crossed that it turns up somewhere
Best wishes,
Bill Rudman
Re: nudibranch extinction? (4)
May 3, 2001
From: Scott Johnson
Hi Bill,
It may be that we haven't been doing enough deeper water searching to find Chromodoris petechialis. I recall seeing a large red spotted chromodorid in a bottle of formalin some years ago. It had been collected a few days before by a special student program at the University of Hawaii called the Marine Options Program. The animal was brought up from a bottom trawl taken in, I believe, about 100 meters of water. The person who showed me the animal was not sure. Unfortunately, I was able to superficially examine it for only a few minutes, and was not able to talk them out of it. Perhaps we can get some of those folks using electronic rebreathers to keep their eyes open for it.
Scott
johnson@kmr.ll.mit.edu
Johnson, S., 2001 (May 3) Re: nudibranch extinction? (4). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4282Re: nudibranch extinction? (1)
May 2, 2001
From: Cynthia Trowbridge
Dear Bill,
Your message about this potential nudibranch extinction is provocative. The problem of many species of opisthobranchs is their very low population abundance. Many taxa are known from only one or a few records. In some cases, once we know where to look (i.e., the specific prey food or habitat), the problem of apparent scarcity is resolved. In other cases, the species are indeed uncommon. To conclude that a species has gone extinct, I think that we need more specific and conclusive information than we have for the nudibranch. Lack of published reports does not always reflect the absence of information. Please let me give two examples from my experience.
First, at Oregon State University, we commonly show undergraduate students a pulmonate 'limpet' (Trimusculus reticulatus) on the shore during the spring Marine Biology class. It was not until I came across Jeff Goddard's paper in The Veliger that I learned our population was outside the known geographic range; in 1997, Jeff et al. extended the species' range north to Washington. So, what I knew to be a common taxon, other malacologists considered to be unusual or absent. So, by soliciting for details about your nudibranch, you may indeed hear of more recent records. On the other hand, not everyone who dives necessarily reads the Sea Slug Forum so you cannot validly interpret the negative information as species absence.
Second, in 1990, I found several specimens of an unknown mollusk that I sent to Terry Gosliner. He subsequently described it as a new species (Runcina macfarlandi Gosliner, 1991). According to Terry's paper, runcinids have been collected from Pacific Grove in 1899 (illustration but no photo or specimen) and one other time; so my record from Oregon represented the 3rd record in a century and the only verified record that was photographed (both Terry and I took pictures) and dissected. Does that mean this thing is rare or endangered? I would argue that we do not have sufficient evidence to support that interpretation. I have not found any more specimens but, then again, I have not looked.
When we look at a species' abundance curve for any community, the vast majority of species in a community are uncommon to rare. There are at least 7 fundamentally different types of “rarity” that have been defined by ecologists; many of these are not at all endangered. To conclude that something that is very, very uncommon is actually extinct is very nebulous. I think it is wonderful to request additional information about your nudibranch species but would be cautious about speculating that it is extinct. Thank you for considering my comments!
• Goddard, J.H.R.; Wayne, T.A.; Wayne, K.R. 1997. Opisthobranch mollusks and the pulmonate limpet Trimusculus reticulatus (Sowerby, 1835) from the outer Washington coast. The Veliger, 40(4): 292-297.
• Gosliner, T.M. 1991. Four new species and a new genus of opisthobranch gastropods from the Pacific coast of North America. The Veliger, 34(3): 272-290.
Cordially,
Cynthia
trowbric@ucs.orst.edu
Trowbridge, C., 2001 (May 2) Re: nudibranch extinction? (1). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4275Dear Cynthia,
I agree that we are very short of information on the distribution, natural history, abundance etc etc of most nudibranch species. That is why I encourage 'non-scientists' to help us 'scientists' out. As you know there are very few professionals studying these fascinating animals, but there are thousands of interested amateurs, divers, photographers and naturalists who are observing them and photographing them. The Forum is a way to encourage this vast army of helpers to share their information.
Chromodoris petechialis is an excellent example of the importance and value of all these extra eyes. This animal is relatively large and Hawaii has been fairly well studied, compared with many tropical localities. By making people aware of the potential extinction of this species, I am hoping that a lot more people will go looking for this species than have in the last 130 years. I realise there are many species which have been recorded only once or twice, but when a large, distinctly coloured species of chromodorid, has apparently escaped the fairly good efforts of Hawaiian collectors in the last 30 years, we must begin to wonder whether it is gone for good.
As we well know here in Australia, where many land animals have become extinct in the last 200 years, it is very difficult to prove an animal as gone for ever. Hopefully, by raising the subject of extinction, with a real example, more of us will become aware that habitat destruction can effect marine animals as well as though on land. despite all this my main aim is to find C. petechialis alive somewhere.
Best wishes,
Bill Rudman
Re: nudibranch extinction? (2)
May 2, 2001
From: John Hoover
Fascinating! I own that issue of National Geographic too, and have wondered about these Chromodorids. However, Zahl includes some slugs from the Great Barrier Reef in his article, so I assumed that the red spotted ones were also not from Hawaii. I certainly have never seen them.
Some random thoughts:
Zahl seems to have photographed his Hawaiian specimens in aquaria. But these two slugs are seen with an old chain in the background, so I wonder how/where they were photographed. I can't see anyone putting an old chain in an aquarium.
Cory Pittman points out that there is a colonial tunicate in the upper left. Offhand, it doesn't look like one from Hawaii, but then again who knows?
Kaneohe Bay is a unique habitat. There's no place else quite like it in the Hawaiian Islands and it's not impossible that a species could be confined to the Bay. I can think of at least one other -- a brachiopod-- whose Hawaiian population might be confined to Kaneohe, although the brachiopod is not endemic to Hawaii.
Kaneohe Bay has undergone lots of environmental changes and degradation in the past 50 years. Dredging, sewage disposal, algae blooms, exotic species, freshwater runoff, siltation, etc., so it's also not impossible that a species confined to the Bay did not survive the changes and went extinct.
Zahl writes that he got some specimens from Makua, which is a quite different habitat from Kaneohe Bay. I have dived in Makua-like environments many many times and needless to say have not seen these slugs. I have done almost no dives in Kaneohe, however, because access is difficult. Yet Kaneohe is the site of the Univ. of Hawaii marine lab, so it has been sampled extensively. University people dive there all the time so I will send this to one of them and see what he says. He's a fish person, but it would be hard not to notice these beautiful slugs if they are still there.
John Hoover
hoover@hml.org
Hoover, J., 2001 (May 2) Re: nudibranch extinction? (2). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4276Thanks John,
I look forward to any progress reports
Bill Rudman
Re: nudibranch extinction? (3)
May 2, 2001
From: Mary Jane Adams
Hi Bill,
I referred the Chromodoris petechialis page to some diving friends in Hawaii. Jack Randall said he has never seen it. Another friend is going to show it to her underwater photo club in Kona. It is so beautiful, I hope it is not extinct. This is a perfect example of how the Sea Slug Forum can accomplish scientific discovery. For your information, the term petechia is used in medicine to describe pinpoint hemorrhages that occur as a result of occlusion of venous blood flow such as strangulation. I have a collection of NG magazines and was able to find the article in the Oct. 1959 issue. I had to laugh at the picture of the guy with his home made mask spearing those vicious eels!
On May 2 I am going on a field trip to the Philippines with Terry Gosliner. I am hoping to have some new submissions for the Forum in a few weeks.
Best regards,
Mary Jane
divepng@yahoo.com
Adams, M.J., 2001 (May 2) Re: nudibranch extinction? (3). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4280Dear Mary Jane,
Thanks for the comment on 'petechia'. Many of the early ship's doctors/surgeons also acted as naturalists so there is a fair spattering of medical terms to be found nudibranch descriptions. I think it was Kelaart, an surgeon with the British Army in Ceylon in the 1850s who described the dorid Asteronotus cespitosus as being 'more like a horrid disease' than a beautiful 'sea nymph'.
Good luck in the Philippines, and I look forward to some interesting messages.
Best wishes,
Bill Rudman
The first known nudibranch extinction?
April 28, 2001
From: Bill Rudman
One of the first photos of tropical nudibranchs I remember seeing was in an article by Paul Zahl published in the National Geographic Magazine (1959) on Hawaiian Marine Life. I can't say that it attracted me to a life of studying nudibranchs, but I still have the copy of that issue of the magazine. Years later when I began to study chromodorids, one photo in that article, of two red-spotted animals, became quite tantalising. It was clearly of a species which had never been seen, or at least photographed this century. The only record I could find of it was Gould's description of Chromodoris petechialis from the US Exploring Expedition of 1838-42.
Scott Johnson & I mentioned this species in his message about Hypselodoris paulinae and I promised then to approach the National Geographic Society for permission to reproduce Paul Zahl's photo in the hope that someone would recognise the species. It is known only from Hawaii on the basis of these two records, the original in the late 1830s and the second in 1959 by Paul Zahl. After some time I am happy to announce that the National Geographic Society has given me permission to use the photo on the website. As you will see it is quite different from any other described species. In shape it is almost certainly a species of Chromodoris, but in colour it is quite distinct from any named species.
Has anyone a photo of this species from Hawaii? - or from anywhere else for that matter. If not, it does raise the intriguing possibility that this species no longer exists. If so it would be, to my knowledge, the first case of a nudibranch extinction. It is not a 'first' I would be particularly happy to be associated with, so if any of you have photos from Hawaii, or have contacts in Hawaii who could do some searching, let's see if we can bring this species back from the dead.
References.
• Gould, A.A. (1852) United States Exploring Expedition during the years 1838-1842. Under the command of Charles Wilkes, U.S.N. Vol 12. Mollusca and Shells. 510pp, with Atlas of Plates, 1856. [296-7, Pl.22, figs 391,391a].
• Rudman, W.B. (1983) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris splendida, C. aspersa and Hypselodoris placida colour groups. Zoological Journal of the Linnean Society, 78: 105-173.
• Zahl, P.A. (1959) Unsung beauties of Hawaii's Coral Reefs. National Geographic Magazine, 116(4) October: 510-525
Best wishes,
Bill Rudman
