Lookalikes to Look Out for – No. 3. – Ceratosoma trilobatum, Ceratosoma tenue & Ceratosoma gracillimum

Lookalikes to Look Out for – No. 3. – Ceratosoma trilobatum, Ceratosoma tenue & Ceratosoma gracillimum

Ceratosoma trilobatum – Ceratosoma tenue – Ceratosoma gracillimum In No. 3 of this series there are actually 3 species to compare. These 3 are quite often confused and there are good reasons for that confusion. All were described not last century but the century before – the 19th century. All can present in different colour
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VEXATIOUS VARIABILITY – No. 3  Goniobranchus splendidus

VEXATIOUS VARIABILITY – No. 3 Goniobranchus splendidus

VEXATIOUS VARIABILITY – No. 3 Goniobranchus splendidus Goniobranchus splendidus is a common and conspicuous species of nudibranch, though endemic to the east coast of Australia, from southern New South Wales to central Queensland. It exhibits variation in presentation, some of those attributed and limited to specific regions within its range.     Variation exists in
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MORE COLONIAL CONSUMERS – Sea Slugs that prey on Ascidians, Bryozoans and Entoprocts

MORE COLONIAL CONSUMERS – Sea Slugs that prey on Ascidians, Bryozoans and Entoprocts

More Colonial Consumers Sea Slugs that graze upon Ascidians, Bryozoans and Entoprocts It’s been mentioned before that the feeding preferences of sea slugs, across the entire group, encompass an extremely diverse range of food types, but conversely, each species usually has an extremely specific diet. In this NudiNote, three other phyla from the Animal Kingdom,
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VEXATIOUS VARIABILITY – No. 2  Goniobranchus geometricus

VEXATIOUS VARIABILITY – No. 2 Goniobranchus geometricus

VEXATIOUS VARIABILITY – No. 2 Goniobranchus geometricus Goniobranchus geometricus, to the uninitiated, can appear very much like a phyllidiid nudibranch if the gill is not displayed – all black and white and lumpy. However there are, from time to time, other variations in the mantle appearance that make you take a second look. All though
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VEXATIOUS VARIABILITY – No. 1 Hypselodoris jacksoni

VEXATIOUS VARIABILITY – No. 1 Hypselodoris jacksoni

VEXATIOUS VARIABILITY – No. 1 Hypselodoris jacksoni There are a number of common species of nudibranch that can exhibit a variability of presentation. These differences can sometimes be put down to geographical location but more than often, not necessarily so. At first it can be confusing but once it is realised that the variations belong
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THE STING’S THE THING – Sea Slug Predators of Anemones and Hydroids

THE STING’S THE THING – Sea Slug Predators of Anemones and Hydroids

“The Sting’s the Thing” Sea Slug Predators of Anemones and Hydroids Have you ever inadvertently brushed past a stinging hydroid during a dive and some small part of your skin, being exposed, receives a searing sting? Or perhaps you have been enjoying the surf and a bluebottle’s tentacles have wrapped around your arm or chest
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PHYLLIDIID SUCTORIAL FEEDING

PHYLLIDIID SUCTORIAL FEEDING

Phyllidiid Suctorial Feeding We are occasionally fortunate enough to encounter and record a nudibranch feeding, that is, to actually see that they are feeding, because most often the process is hidden from us beneath them. In those instances, with the sponge-feeders, the buccal mass can be seen protruding and pressed against the sponge tissue that
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SPONGIVORES – The Sponge Eaters

SPONGIVORES – The Sponge Eaters

SPONGIVORES – The Sponge Eaters Sponges (Phylum Porifera) are one of simplest and oldest of multicellular animals. They have the least complex body form of the multicellular animals. Only a few specialist predators are known to be exclusively spongivores, that is, to have a sponge diet and these are disproportionally represented in the sea slugs.
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SLUGIVORES – SEA SLUGS THAT PREY ON SEA SLUGS

SLUGIVORES – SEA SLUGS THAT PREY ON SEA SLUGS

Slugivores – Sea Slugs That Prey On Sea Slugs The great majority of sea slug species are carnivorous, meaning they prey on animal life rather than plant life. It is often not appreciated that sponges, bryozoans and hydroids etc. although primitive life forms, and appear to grow like plants, are animal life forms all the
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HITCHIN’ A RIDE ON THE SEA SLUG TRAIN

HITCHIN’ A RIDE ON THE SEA SLUG TRAIN

  Hitchin’ a Ride on the Sea Slug Train It is often said there is no such thing as a free meal, but what about a free ride to collect your meal? One sees sea slugs on many sessile invertebrates either feeding or traversing but only occasionally does one see invertebrates upon sea slugs. In
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THE ALGAE GRAZERS

THE ALGAE GRAZERS

  The Algae Grazers (Header image above – Petalifera ramosa) It has long been established that the algae are the base upon which the marine food web is built and sustained. Algae are an important food source for numerous marine animals across many different phyla and the sea slugs are no exception. (Algae, in the
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THE CORAL EATERS

THE CORAL EATERS

Many people are surprised to learn that some nudibranch sea slugs are actually corallivorous, that is they feed upon corals. Those that keep corals in aquariums however know only too well the havoc certain nudibranchs can cause particular corals. Corals don’t look to be particularly appetising but a little explanation of their anatomy will help.
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GIVING THE FINGER – The siphon of gastropterids

GIVING THE FINGER – The siphon of gastropterids

The Gastropteridae are cephalaspideans or head-shield slugs. It would appear that their “main claim to fame”, bright and dramatic colouration of many aside, revolves around the ability and propensity of many to swim by flapping their parapodia. This behaviour has led to them receiving the common name of “bat-winged slugs”. Behaviour, especially one so demonstrative
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SPECIFICITY IN DIVERSITY – The diet of sea slugs

SPECIFICITY IN DIVERSITY – The diet of sea slugs

Across the entire group, the sea slugs have an extremely diverse source of food types, but conversely, each species usually has an extremely specific diet restricted in many cases to one or only few, usually closely related, prey species. A list of the animal types preyed upon reveals that all the major invertebrate phyla are
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Lookalikes to Look out for – No. 2. – Mexichromis pusilla & Verconia varians

Lookalikes to Look out for – No. 2. – Mexichromis pusilla & Verconia varians

Mexichromis pusilla – Verconia varians In No. 2 of this series Mexichromis pusilla (Bergh, 1874) and Verconia varians (Pease,1871) will be discussed. Both species were described back in the 19th century and have gone through a couple of name changes. The original genus for both was Chromodoris. There had been much confusion in the literature
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FOUR AND MORE INTO ONE – Variation in Miamira moloch

FOUR AND MORE INTO ONE – Variation in Miamira moloch

Miamira moloch is a large to very large nudibranch of the Chromdorididae Family. It was first described as Ceratosoma moloch in 1988 by Rudman from two specimens, one collected from Heron Island, Central Queensland and the other from North Stradbroke Island, Southern Queensland. At first glance the specimens in the above montage all appear to
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REMARKABLE RHINOPHORES

REMARKABLE RHINOPHORES

When you don’t possess true eyes to recognise the shape of things, to see where you’re going, or what’s coming, then you must certainly have some other highly developed sense to survive. Living in a medium that has thousands of different compounds dissolved or suspended in it, a virtual soup of chemicals, released either intentionally
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STALKING WORMS  – FEEDING BY Mariaglaja inornata

STALKING WORMS – FEEDING BY Mariaglaja inornata

The Aglajidae are a carnivorous group of headshield sea slugs that actively hunt their prey. They are mostly fast moving in order to capture other sea slugs and polychaete worms. They are well-adapted for the task with clusters of sensory bristles located on the front of their broad headshield, on mounds both sides of the
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Lookalikes to look out for – No. 1

Lookalikes to look out for – No. 1

Sometimes when reviewing images post-dive it’s easy to overlook an uncommon species if it has a similar appearance to a species that is frequently sighted. We know the common one well but have forgotten about the rarer one that looks similar – The Lookalike. This NudiNote will discuss a not-so-common species – Verconia decussata (Risbec,1928)
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HANCOCK’S ORGANS – THE “RHINOPHORES” YOU HAVE WHEN YOU DON’T HAVE RHINOPHORES

HANCOCK’S ORGANS – THE “RHINOPHORES” YOU HAVE WHEN YOU DON’T HAVE RHINOPHORES

We all know about the rhinophores of the true nudibranchs – those highly developed chemical-detecting “antennae” located anteriorly on their “head”. Even sea slugs other than the true nudibranchs such as the sea hares, and the side-gilled pleurobranchs have rhinophores. These though are tubes formed by longitudinal rolling rather than the solid form of the
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“WELL, THERE’S SOMETHING YOU DON’T SEE EVERY DAY.” – Tenellia sibogae

“WELL, THERE’S SOMETHING YOU DON’T SEE EVERY DAY.” – Tenellia sibogae

Tenellia sibogae (or Trinchesia sibogae, depending on whose taxonomy you follow) is usually sighted upon its food – arborescent hydroids of the Sertularella genus (usually identified as Sertularella diaphanous or Sertularella quadridens). If you are searching for sea slugs and spot this characteristic looking hydroid it is definitely worth your time to search through it
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SIX SEPARATE SOCKETS – Hexabranchus

SIX SEPARATE SOCKETS – Hexabranchus

Hexabranchus sanguineus The name says it all. It has six gills – Hexabranchus, and is blood-coloured – sanguineus. This species was originally described from the Red Sea. Specimens from that region are not red and white mottled as in the images posted here but are a deep and uniform “blood” colour. This nudibranch, also known
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UNIQUELY UNITED BUT DECEPTIVE DISPLAY – THE SUCTORIAL FEEDING POROSTOMATA NUDIBRANCHS

UNIQUELY UNITED BUT DECEPTIVE DISPLAY – THE SUCTORIAL FEEDING POROSTOMATA NUDIBRANCHS

UNIQUELY UNITED BUT DECEPTIVE DISPLAY The Suctorial Feeding Porostomata Nudibranchs In a previous NudiNote – The Little Scraper – the radula of sea slugs was discussed. Mention was also made of those sea slugs that do not possess a radula. Among the dorid nudibranchs in particular, the radula has only been lost once along their
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AUTOTOMY – THE SELF SACRIFICE DEFENCE

AUTOTOMY – THE SELF SACRIFICE DEFENCE

Autotomy – the Self Sacrifice Defence   The ability to cast off a particular section of their anatomy, in order to facilitate escape from a predator, is possessed by a wide range of animals. Although the phenomenon, even in the Mollusca, had been recognized previously the term wasn’t coined until 1883 by Leon Fredericq as
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VIVA VARIATION – Hypselodoris bullockii & LOOK-ALIKES

VIVA VARIATION – Hypselodoris bullockii & LOOK-ALIKES

VIVA VARIATION Change is upsetting    Repetition is tedious.       Three cheers for variation! Mason Cooley Across all of the Sea Slugs there is an almost endless amount of variation. Different shapes, sizes, textures, patterns and colours. We aficionados of the Sea Slugs enjoy all of that variation for it gives us many
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THE LITTLE SCRAPER – THE RADULA

THE LITTLE SCRAPER – THE RADULA

The Little Scraper Nearly all the sea slugs, just like nearly all the molluscs (except the bivalves), possess a radula in the buccal cavity for feeding. The radula is used not unlike a combination of teeth and tongue to rasp at, puncture, slash or grip the prey for ingestion. Salivary glands assist the action of
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SORTING OUT THE TRUE NUDIBRANCHS

SORTING OUT THE TRUE NUDIBRANCHS

Sorting out the True Nudibranchs   The Nudibranchs are but one order, the Nudibranchia, in the informal group that we refer to under the umbrella of Sea Slugs although common and popular usage has seen the term Nudibranchs used incorrectly to refer to all the sea slugs in general. This NudiNote is concerned just with
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THE EXCEPTION TO THE RULE – Phyllodesmium acanthorhinum

THE EXCEPTION TO THE RULE – Phyllodesmium acanthorhinum

THE EXCEPTION TO “THE RULE” Phyllodesmium acanthorhinum is a rarely sighted, though widely distributed, species first recorded from Okinawa by Bob Bolland in 1987. The 15 mm long specimen pictured here was found in the Mooloolah River, southern Queensland, Australia in 3 m of water. It had long been thought that species of Phyllodesmium only
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CONGRESS ON CODIUM – Elysia maoria

CONGRESS ON CODIUM – Elysia maoria

CONGRESS ON CODIUM All of the sea slugs in the Sacoglossa order are herbivorous, well nearly all, a very few prey on the eggs of other sea slugs. However, that great majority that feed on plants do so by puncturing the cell walls of algae and sucking out the contents. The sacoglossans are a very
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THE ANAL DUALITY OF THE NUDIBRANCHIA

THE ANAL DUALITY OF THE NUDIBRANCHIA

The true nudibranchs are divided into two suborders – Suborder Cladobranchia and Suborder Doridoidea. Without doubt the most noticeable external difference between the two is in the appearance of the gills. Here we must generalise of course with the dorids having a circle of gill branches around the anus, sometimes presenting as an arc or
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WHAT PHYLLIDIID IS THAT?

WHAT PHYLLIDIID IS THAT?

Trying to decide to which genus a phyllidiid nudibranch belongs from a photo can be a task of some difficulty. There are some external features that can be used, but these are not always easily observed. Here is a rough external guide boiled down to the basics: Phyllidia – Oral tentacles separate; rhinophores cream, yellow or
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