Discussions
THE VARIETY PACK
 In our hunt for the ever-elusive next species to add to our list there is always some degree of conflict existing in the vision we hold in our minds eye of what we are actually looking for. On the one hand we have images of all those known shapes, patterns and colours and combinations thereof of species that we have already found. Intertwined with that is the expectation of something different appearing either as a variation upon a common theme or an entirely novel find. At times what does turn up may be a pattern of colours that are recognizable but they are on a body shape that is different to that upon which you would normally find it. Conversely it may be a familiar body shape but it bears an unfamiliar pattern or colour.
When a taxonomist describes a new species it is not always possible for every existing variation to be included in the paper. There are a number of probable reasons for this. It might be that they have been lazy and only concerned themselves with a few or even only a single specimen from a single locale. It is also true that the range of distribution may not be fully known and that over that range there is a graduation of presentation. Sometimes they include the caveat that "a wide range of colouration has been observed" and leave it at that. The increasing interest in and recording of sea slugs would also account for more and more variations coming to light.
Usually though there is some external physical feature or perhaps combination of features that enable a link to be made between widely differing colour forms of the same species.
Just last week in fact we found variations of Chelidonura fulvipunctata on the one dive trip to a site we call Nudi Ledge off Caloundra on the Sunshine Coast, Queensland. Not unusual you would think, except that there were 4 variations and all 4 were observed within the length of our 40 metre dive reel. Without a doubt we had found the "Variety Pack".
The photos here show:
- Black background with large greenish-orange spots
- Translucent cream background with light brown peppering and white spots to the parapodial edges
- Brown background with white peppering and white spots to the parapodial edges
- Black background with small white spots and white trim along the full length of the parapodial edges (very much like C. inornata)
(Go to the species page to view larger images)
If it wasn't for all of these specimens also exhibiting the distinctive W shaped mark on the head (or part thereof), the large white tip to the posterior end of the headshield (halfway down the length of the body), the distinctive spots on the foot (not visible in all pics here) and the distinctive long and tapering left tail, we may have been tempted to argue for some separate naming.
Text by David Mullins
Photos by Gary Cobb & David Mullins
A LITTLE DIFFERENCE IN DECORATION
 Chromodoris decora is one of those nudibranch species that while found occasionally under rocks intertidally is only rarely seen subtidally. It is a small species with disruptive colouration and is probably often overlooked. Through various reviews the name has changed from Doris decora to Glossodoris decora and is now known as Chromodoris decora.
We all recognize Chromodoris decora by a couple of distinctive features. The mantle has three thin, white, longitudinal lines. The outside white lines continue around the front of the rhinophores and the back of the gills, together forming a loop. The medial white line often forks in front of and around the gills. There are purple spots between the white looping line and the orange border to the mantle. There may also be purple spots inside the looping line and also on the medial white line. The rhinophores and gills are uniformly cream.
Pease first described this slug from Hawaii as Doris decora in 1860 but did not include an illustration. His description however contained the following: “…..a medial whitish longitudinal strip which is bifurcated posteriorly and dotted with purple”.
Berg in 1880 published an illustration of a slug recognizing the name that Pease gave it earlier and which clearly showed the features described.
In 1938 Baba described a similar animal but although it did have a white forked medial line, that line did not bear the purple spots. He named his animal Glossodoris setoenis. Later, in 1953, Baba suggested that his animal should now be considered a synonym of Pease’s decora. Gosliner, Behrens & Valdes, (a) list this type as Chromodoris setoenis (Baba, 1938) with the notation: “Additional work is necessary to determine whether these are color variations or distinct species.” Marshall & Willan, (b) are of the opinion that it is a synonym, as is Rudman, (c).
All of the specimens of Chromodoris decora that we have found to date in southern Queensland waters have been of the “Baba variety”, that is, without purple spots on the white medial bifurcated line. This type appears to have a wider distribution and therefore seems to be much more common than the type originally described by Pease. Pease’s type definitely has a more “easterly” Pacific distribution e.g. Hawaii, Guam, Tonga and New Caledonia.
Read more:
(a) Gosliner, Behrens & Valdes, Indo-pacific Nudibranchs & Sea Slugs, 2008, p. 224
(b) Marshall & Willan, Nudibranchs of Heron Island, 1999, pp. 93-94
(c) Rudman, www.seaslugforum.net, Message # 20717, 2007
MAKING SENSE OF SIMILAR VARIETY
 When you have set yourself a goal to find all the species of sea slugs in a certain area or region there are certain methods by which the search can be continually driven. One of those methods is to set other goals, such as a species count that must forever be driven upwards. Unfortunately by focusing purely on increasing that count we can sometimes lose sight of what we are really trying to achieve.
Just the other day we were trying to convince ourselves that some differences in mantle colouration and pattern were sufficient to call a specimen a different species. Some further research on similar looking species only served to confuse us. The particular group in question are those in the Chromodoris tinctoria (top photo) and Chromodoris reticulata (bottom photo) sphere.
In reviewing those species on all the websites and in all the books available to us as well as images forwarded to us by like-minded colleagues, we were overwhelmed by a virtual constellation of variety, but similar variety we might add. This description might be an oxymoron but it serves to highlight our dilemma. How to make sense of this?
The Sea Slug Forum takes the view that they are all but variants of just one species, a continuum of variety and similarity all linked by virtue that “….the species differences suggested by different colour patterns is not supported by internal anatomy.” The Forum further suggests that the differences are mainly associated with colour and pattern at the mantle edge. As the earliest name for any of the described species in this group was Doris tinctoria Ruppell & Leuckart, 1830, they are all grouped on the Forum under Chromodoris tinctoria (Ruppell & Leuckart, 1830).
Gosliner, Behrens & Valdes in their recent book Indo-Pacific Nudibranchs & Sea Slugs take the completely opposite and extreme view by listing members of this group as 11 distinct species on the basis of the colour patterns in photographs. They justify this position with the assertion that: “….there are consistent differences between specimens from different geographical localities.”
These are obviously the two extreme positions in this debate.
Our colleague Richard Willan on the other hand (Nudipixel & personal correspondence) leans towards the conservative end of the spectrum, believing there is no evidence to warrant calling them all different species, and commenting: “Whatever the species boundaries are, and whatever the name(s), it is clear the species within this group are highly variable.” He does however divide them into two broad groupings on the basis of observable external anatomical features namely, the number of gills and the size of the adult, as follows.
Chromodoris tinctoria (Ruppell & Leuckart, 1830):
Small when adult and less than 8 gills.
Chromodoris cf. reticulata (Quoy & Gaimard, 1832):
Large when adult and more than 12 gills.
Richard’s use of reticulata is explained thus: “…it was clear the name C. reticulata was becoming prevalent, through ignorance, on lots of internet sites. This is because the name can be matched to a reasonably good and recognisable drawing by the French scientists Quoy & Gaimard in 1832.” and further “So…I used reticulata, together with the cautionary “cf.” to indicate there was uncertainty that the southern Qld species matched the true C. reticulata (whatever it might be), in Undersea Jewels.”
We find this latter argument convincing. Our mindset has now been changed not only to finding all of the species, but also all of the many variations to all those species, which can be just as rewarding even though it does not increase our species count. It is human nature to try to understand and make organisation out of perceived chaos. One of the tried and tested methods is to classify everything according to an accepted code. However as Richard responded to one of my identification questions: “Essentially your question/observation strikes at the heart of all opisthobranch taxonomy. What are the limits of a species? That question still remains subjective, even though the answers might be morphologically based or (more and more nowadays) genetics based.”
Where then does this leave the differing opinions on this group? Richard Willan’s summing up is thus: “All I can do at this time is repeat their (Gosliner et al) words: ‘The entire group is in need of a major review.’”
Spurilla neapolitana
Spurilla neapolitana is a nudibranch species now showing a wide-range of distribution. It is now considered to be a tramp species in many parts of the world with the assistance of human activities most likely through the action of commercial shipping.
There is an excellent and elucidating article written by Richard Willan and published in the Malacological Society of Australasia’s Newsletter (No. 130 October 2006) from which the following excerpts and information are taken.
“Nudibranchs are especially good at hitching rides on ships’ hulls; one could describe them as long-distance back-packers. Their rapid life cycles, high reproductive output, physiological adaptability and opportunistic diets, have preadapted them to travel widely round the globe thanks to mankind’s sea voyages.”
“Spurilla neapolitana was first described in 1823 from Naples in southern Italy. Its spread around the world over the last 50 years has been truly meteoric, with records from the tropical western Atlantic, California, tropical eastern Pacific, Hawaii, Japan and Hong Kong.”
Our colleague, Denis Riek of Brunswick Heads, made the first Australian find in May of 2005 and it has been reported a number of times since from various localities along the New South Wales coast. This intertidal find at Caloundra is a new record for Queensland.
The sudden appearance of Spurilla neapolitana in many parts of the world has workers in this field confusing it with local species and even recording it as a new species.
The distinguishing characteristics, especially pronounced in the adult, are the lamellate rhinophores, the long and slender cerata coiled near the tip, and the white spots all over the body and cerata. The diet of Spurilla neapolitana is sea anemones, and a wide variety of sea anemones at that, with the type and colour of those consumed contributing to the background colour of the slug’s body, which can be brown, pink or red.
How to tell if it is a Janolus
Our species list now contains two Janolus.
With a profusion of cerata on their dorsum Janolus could easily be mistaken for an aeolid, but in belonging to the Zephyrinidae family the Janolus are armininans not aeolids. Although having an aeolid-like form the most readily observable feature of distinction is that in the Janolus the cerata continue uninterrupted around the anterior margin of the head, a feature no aeolid possesses (refer pic above, from The Collection).
A further helpful attribute of distinction is the location of the anal papilla. In Janolus it is located on the dorsal midline posteriorly (see Erik Schlogl's message at www.seaslugforum.net/message/19798), whereas in the aeolids it opens to the right anterior quarter usually on the side. Whilst the rhinophores are non-retractile in both the Janolus and the aeolids, the Janolus possess a distinctive ridge between the rhinophores at their bases. This longitudinal ridge is called a caruncle and its purpose is unknown, although some have variously suggested it performs a sensory or defensive purpose.
WHAT’S A FREAK?
(COLOUR FORMS AND DISTRIBUTION)
 It is to be expected that the more you dive the more unusual sights you will see. Then again you might think that the odd or unusual observation may become commonplace or at least a pattern develops that explains the atypical.
We had a pleasant dive on the HMAS Brisbane wreck last week and apart from some nice finds a couple of unusual things came to our attention.
The first concerns Tambja tenuilineata a small polycerid that we regularly find right across the Gneering Shoals and at Old Woman Island, grazing upon bryozoans. It is recognized by its green body colour with numerous narrow black longitudinal lines, and green rhinophores and gills tipped in purple. This is how it always presents to us - or so we thought. On this dive we found a plain specimen without the black stripes but with wrinkles or furrows instead. A search of our records revealed that we had found this colour form once previously - approx 12 months ago - also on the Brisbane. So far therefore - no stripes only on the Brisbane but with stripes everywhere else. Perhaps we will allow a few hundred more dives to pass before we attempt to draw any wild conclusions from these observations.
The second is with regard to Chromodoris splendida, a very common almost ubiquitous species here. All divers are familiar with its “strawberries and cream” appearance, with the red colouration in our region presenting as a single or group of large blotches on the dorsum. Over the past 7 years, of the many hundreds sighted we have only once found it without any of the red blotches. This was at Old Woman Island. Last week on the Brisbane we saw many of the usual sort but also two specimens without the red blotches. When first observed without these red blotches their appearance is a little disconcerting and one can’t at first establish what is wrong about it. Check the gills, check the rhinophores, and check the band on the edge of mantle and foot. All present and correct. Another oddity recorded.
Finding an oddity for the second time makes it less of a freak to be ignored and more of an acceptable, recordable variation.
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Latest News
08 January 2012
RECENT NEWSPAPER ARTICLE
Its a great moment when the newspaper prints an article on Sea Slugs and the guys who look for them.
24 September 2011
TEAM ON BOARD MISCHIEF
After our dives at Flinders Reef Moreton Island, David Mullins, Terry Farr and Julie Schubert of the Nudibranch.com.au Team relax on MISCHIEF.
Often after our dives we review what we had found while eating and hoping the last Nudibranch we found was indeed the latest and newest species to our list.
On this trip 24-09-2011 David found number 473! At 9 mm long and hard to see, we positioned Trinchesia sp. 9 onto our black slate to get a taxonomic photo, one where the whole animal is seen without interference of sea life and substrate.
20 September 2011
FLUCTUATIONS
 One of the species most commonly recorded by us in our survey area is Thuridilla splendens (B), a sacoglossan that we have found in multiples on just about every dive, except those in the Flinders Reef region where Thuridilla neona (D) and Thuridilla gracilis (C) seemed to predominate. Subtidally T. splendens has been the most common of all the Plakobranchidae family members seen by us.
Back in September of 2009, and well over 6 years into our survey, we found in our area a single specimen of a new species for us, Elysia sp. 5 (A), another Plakobranchidae member. That single observation was followed by a drought of 18 months where it was not sighted at all. The past few months however has seen a complete turn about whereby T. splendens is only occasionally sighted but Elysia sp. 5 turns up on nearly every dive across the whole area and in multiple numbers as well.
This Elysia sp. appears to have a distribution along the subtropical east coast of Australia and New Zealand. Neville Coleman has a 1985 image of it from Coffs Harbour in his Nudibranchs Encyclopedia. The Sea Slug Forum has our Elysia sp. 5 recorded as their Elysia sp. 4 with a photo taken by Bill Rudman back in May 1986 at Botany Bay, New South Wales, Australia and a submission from New Zealand in 1999. Entries on Nudipixel for this species have all originated from central or southern New South Wales and our industrious colleague Denis Riek on the northern coast of New South Wales has not reported it from his area at this stage.
What are the circumstances that see the population of one species dramatically rise and that of another, a relative, fall? Could it be a combination of factors? Perhaps the combination of all the rain this summer together with the drop in water temperature during winter led to an increase in the food availability for one species but a decrease for the other?
Questions, questions, questions.
Text and Photos by David Mullins
02 June 2011
FAREWELL RV GODIVA
WELCOME RV BEAGLE
 Following our nasty incident involving a trawler without a lookout last January good old faithful RV Godiva has been written off. It was a very sad day when we had to let her go but we bolstered our spirits by recalling all of the wonderful and reliable adventures she took us upon.
With an uncompleted mission to finish (will it ever?) our thoughts quickly turned however to a worthy replacement. Internet, Trade-a-Boat and Boatyard searches failed to turn up a suitable second-hand vessel. There were several candidates in the new boat market and so our inquiries therefore concentrated upon which of these would provide the best platform to cater to our research needs. Reading magazine and internet reviews, taking demonstration models out for test runs and speaking with various boat builders about the various modifications we wished to incorporate took several weeks.
In the meantime the hole in our diving program was filled by our big power cat Mischief and also by the Caloundra Team (the wonderful Terry Farr & Julie Schubert) who stepped up and took us out a number of times in their vessel. A great deal of fun and follies was had by all on these crowded trips.
We eventually settled upon a 5.0 metre Brig Eagle twin console Hypalon RIB, powered by a 100hp Yamaha 4 stroke outboard. The ride, handling and economy of this inflatable rig are astounding. In reality it was never going to be any other type of boat but a RIB once we reflected upon the impact and damage Godiva suffered and yet still remained afloat. We now have a canopy for shade, built in fuel tank, fresh water shower, boarding ladder, tank racks and both ride and kit-up seats. All we need now is someone to wash out our gear afterwards and we will have it made. We are also equipped with a radar reflector mounted upon a 3 metre pole but if they are not looking they won't see us!
The new vessel has been named RV Beagle (photo above) after the vessel HMS Beagle in which Charles Darwin made his famous around the world trip (and Brig Eagle can sound a bit like Beagle if you say it fast enough). Beagles are renowned for sniffing out specific items and we hope to "train ours to find Sea Slugs". Seriously though, with all these features and the comfort and range now afforded us we will have no excuse for not sniffing out some new species of Sea Slug ourselves.
Our thanks to Dylan & Tom of Sirocco Marine North at Coomera - hull & trailer; Ben of Lewie Marine at Coomera - diving modifications; Chris of C.M. Marine Electrical for electrics and instrumentation; Paul & Ryan of Yatala Yamaha at Yatala - for a great job with supply and setup of the power unit. It all came together guys!
(For the full story on the Godiva incident read the March 2011 issue of DiveLog.)
12 May 2011
The NEW Team Shirts
Have a look at the NEW Team t-shirt. Terry and Julie proudly show off their new shirts! Click on the photo here to see a larger photo.
The shirts are covered completely in Nudibranch drawings from a German book called Opisthobranchia des Mittelmeeres by L. Schmekel and A. Portmann.
These shirts are not for sale and we have acknowledged the authors on the shirts. Thanks.
26 April 2011
Fabulous Flinders - Fabulous Finds
 The Gods of wind, waves, swell, current, viz and sea slugs all smiled kindly upon our intrepid team during the latest excursion out to Flinders Reef undertaken last Friday. It was not only Good Friday but also definitely a very good Friday once the results of this trip were tallied up.
Our research vessel Mischief sped five dedicated slug hunters out past Cape Moreton to the eastern side of Flinders Reef in the Aladdin's Cave area for a serious sea slug survey.
Terry Farr, Julie Schubert, Gary Cobb, David Hill and David Mullins all made the most of the wonderful conditions to post some new records for sea slug finds. Although only covering an area of less than a semicircle of 50 metre radius, our cameras never stopped firing at the amazing assortment of opisthobranchs spread out before us.
The excited team enjoyed a well deserved lunch off Bulwer Beach afterwards, comparing the pics in our cameras, sharing our individual recollections of the morning and commencing our list of fabulous finds.
The remarkable stats are:
- 5 divers each with two x 100 minute dives
- 15 metre max depth and 25 metre plus viz
- No current and very little surge
- 47 different species of sea slug found - a record number for an outing
- 5 species new to our list - also a record number for an outing
- 4 of the new species are undescribed
For a full listing of species found check out the Blogger for 22nd April 2011.
23 March 2011
 Nudibranch ID App finally here!
This iPhone field guide by Gary Cobb will place right at your fingertips, anytime and anywhere, an outstanding selection of 700 species of Nudibranch found in the Central Indo-Pacific Region from Japan to Australia, a zone where marine fauna diversity is at its greatest.
>>> No web connection required!
Nudibranch Facts - Information about Nudibranchs, what they are and what makes them so interesting and unique in the underwater world.
Species - An alphabetical listing of 700 species of Nudibranch to be found in the Central Indo-Pacific Region in a scrollable index that provides access to individual species pages containing a large photo and information about
the selected species.
Families - Descriptions of the 56 Families represented in this App providing external morphology information that allows comparison and contrast between the Families.
Images - The Images Gallery is a scrollable screen of Nudibranch thumbnails. They are presented 4 across the screen providing
24 "at a glance" images.
Search - Full seach ability. Seach for information from the Species pages. Use whole or parts of text.
For more information Click here
Get it at iTunes NOW! Click here
31 January 2011
MOTHER NATURE WINS!
Due to weather conditions here in Southeast Queensland the team has not had alot of opportunities to get out there and find new Nudibranchs. Floods and big rains have wreacked havoc with the reef systems.
18 September 2010
 HOW WE SEE THE SMALL ONES!
We have designed an eye glass attachment that works and is interchangable underwater. This new system allows the diver to get up close.
When the question comes up..."How did you see that one?" we simply say because we wear powerful glasses that allow us to see small animals.
 The case is clipped onto the BCD and when glasses are not used are stored in the case for protection. The glass frame is worn over the outside of the mask and can be positioned to suit. By wearing the glasses on the outside of the mask it eliminates fogging problems. Click on the photos to enlarge!
If you are interested in this system email Gary and we will prepare you a set for $300AUD not including shipping. Orders must be paid in advance via PayPal.
14 November 2009
A BURROWING GYMNODORID!
 This unusual species of gymnodorid was found whilst sieving the dark and muddy silt on the intertidal flats at Woody Point. The water depth was approx 300 mm at low tide.
The general body shape is that of a typical gymnodoris; soft, elongate and tapering to a tail. The mantle is much reduced to a skirt around the anterior end. The body is transparent with the viscera clearly visible and is covered with numerous very fine red spots.
There are though three extraordinary attributes immediately apparent that mark this species apart from the typical gymnodorid:
- The gills are reduced to a single tapering and undivided translucent triangle which is immediately preceded by a slightly raised white ridge curving protectively in an arc.
- The rhinophores are fused and located in a pocket.
- Instead of crawling at speed around the container hunting for prey it spends its entire time going through contortions in attempts to burrow.
These physical features appear to be adaptations for burrowing and, together with its behaviour, point to an infaunal lifestyle. It obviously hunts for prey within the substrate.
12 November 2009
THE DAILY TALLY
We are now publishing a species list of all the sea slugs found upon each dive trip. The digital camera with its huge memory capacity has made this possible as we can take a quick pic of each species found. Those pics may not win a prize for composition or exposure but they are a ready reference to corroborate our recollection of sightings after the trip.
If you click upon NUDIBRANCH CENTRAL BLOGGER (in the navigation barat the top left of each page) it will open up our blog page. Following each trip we will list here all the species found at that site on that date. There is even a facility there for you to post a comment which can include any questions you might have.
It is our intention, sometime in the near future, that this information about species, sites and dates will be entered into a database allowing us to generate statistics, for example: Where has a certain species been found? What is its frequency of occurrence? What species have been found at a particular site? Which species are seasonal?
The ultimate extension to that is the desire to make access to the database also available to readers allowing them to search for this information themselves from our site. But first all the ground work has to done to collect the data in the first place. At first we regretted that we had not done this from the beginning of our quest over 6 years ago which would have provide us with much more data, however we now believe that in the early days our hunting/observational skills left a lot to be desired. With these skills honed over that period we are now more likely to produce a more accurate daily tally of the opisthobranchs that are there to be found. (Slugs are where you find them.)
29 October 2009
BUILDING CARICATURE
Mimicry in the animal and plant world is a most interesting area of study because it raises so many questions about relationships between quite diverse levels of life.
I can remember being told, when complaining about some one copying me or what I was doing, to not worry about it and that: imitation is the greatest form of flattery. Being very young at the time I considered these people to be a much lower form of life anyway.
In the Sea Slug world it probably has more to do with survival by appearance than anything else.
Zoologists talk about Batesian and Mullerian types of mimicry but we believe we have stumbled upon a 3rd type. We think we can demonstrate this 3rd type of relationship between some Sea Slugs and inanimate “objects” although these “objects” are far more famous for their animation.
 Look, for example, at this picture of a species of Atys. There is without doubt a definite similarity between it, when viewed from the anterior end, and a certain type of feline. Our research has pinpointed the feline in question to be without the shadow of a doubt as none other than 'Felix the Cat'. Note the extreme similarity with the ears of each, and don’t be put off by other unimportant anatomical differences.
We are calling this new type of relationship Cartoonian mimicry. We have not been able to establish definitively as yet just what either gains from this but further research will no doubt supply the answer. Early interpretations of our data lead us to believe that Felix gains the cute look which has made him so famous the world over whilst Atys can now claim some celebrity status even though leading the quiet infaunal lifestyle. Cartoonian mimicry requires a different mindset to comprehend fully. Whilst recognition is an important aspect it is not about survival but about fame. It’s not about deception but about adulation and entertainment! Yes, this opens up whole new fields of study for those with the perception and idle hours to fill, to lead the way.
As a mark of recognition we are conferring a common name upon this species. Until such time as it is formally described by taxonomists we are referring to it not only as Atys sp. 4 but also Felix the Atys.
(in gaudio absurdum)
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