#seaslug — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #seaslug, aggregated by home.social.
-
Goniobranchus rufomaculatus: Nudibranch of Lembeh Strait
https://www.youtube.com/shorts/Sh3GGkFUDbk
Want to encounter these marine creatures in person? Find trusted dive centers worldwide.
Browse Reviews →Goniobranchus rufomaculatus: Nudibranch of Lembeh Strait
Marine BiologyOut on the open sand in Lembeh Strait, Indonesia, this nudibranch immediately stood out—not for its color, but for how fast it was moving. While nudibranchs are famous for being slow, this individual was covering the seabed at a noticeably brisk clip. It is Goniobranchus rufomaculatus: a small white nudibranch scattered with yellow dots, rimmed along its scalloped mantle edge with blue-violet spots.
Species Identification
Scientific Name Goniobranchus rufomaculatus (Pease, 1871) [1] Classification Dorid nudibranch; family Chromodorididae [1] Synonyms Chromodoris rufomaculata Pease, 1871 (basionym); Chromodoris histrio Bergh, 1877; Glossodoris rufomaculata (Pease, 1871) [1] Appearance Smooth white-to-cream mantle stippled with small yellow-orange dots; scalloped mantle margin ringed with discrete oblong blue-violet spots (not a continuous band); rhinophores and gill plume pale translucent white [2] Size Reported up to ~2.8 cm (1.1″) [6] Diet Sponges — a feeding pattern well documented across the wider Chromodorididae family [3]; direct dietary records specific to this species are limited Range Documented from the Society Islands (type locality), the Marshall Islands, Queensland (Australia), and the Philippines [1]. This post’s Lembeh Strait, Indonesia sighting is a firsthand field observation, not a formal range record. Conservation Status Not evaluated by the IUCN — typical for nudibranchs generallyBiology & Ecological Role
Across the wider Chromodorididae family, sponges are the primary food source, and several species are highly specific about which sponge they’ll eat.[3] Direct feeding records for G. rufomaculatus specifically weren’t found in the sources checked for this post, but the pattern is well established at the family level.
Many chromodorid species turn that sponge diet into a defense: they absorb chemical compounds from their prey and store them, largely unchanged, in their own tissue. In studies of related white-bodied Goniobranchus species, these defensive compounds tend to concentrate most heavily along the mantle rim.[4] Whether G. rufomaculatus follows this exact pattern hasn’t been directly tested — but if it does, the placement lines up neatly with the blue-violet-spotted edge that makes this species so recognizable, a predator’s first bite landing right where a toxin might be waiting.
Like other nudibranchs, this species is expected to be a simultaneous hermaphrodite — carrying both male and female reproductive organs. In mating nudibranchs generally, two individuals line up right side to right side and exchange sperm, so both partners go on to lay eggs, typically as a spiral ribbon of gel attached to the reef.
Field Notes & Observations
Watch the margin, not the body. The blue-violet spotting described in the original 1871 species description[2] runs along the scalloped mantle edge — the body itself is white with yellow dots, not blue.
Similar species exist, and they’re hard to separate from a single photo. White-spotted Goniobranchus is a genuinely unresolved group taxonomically — a 2024 molecular study found that G. rufomaculatus is not closely related to the similarly colored G. aureopurpureus despite the resemblance, and identified open questions about where G. rufomaculatus ends and G. albopustulosus begins.[5] If you’re trying to confirm an ID on a similar-looking animal, the full margin pattern, mantle texture, size, and location all matter — and a comparison photo or a second opinion goes a long way.
References
- WoRMS / MolluscaBase — Goniobranchus rufomaculatus (Pease, 1871). marinespecies.org ↩
- Pease, W.H. (1871). Original species description. American Journal of Conchology 7(1): 11–19. Biodiversity Heritage Library ↩
- Rudman, W.B. & Bergquist, P.R. (2007). Feeding specificity in the sponge-feeding Chromodorididae. Molluscan Research 27(2): 60–88. ↩
- Distribution of Defensive Metabolites in Nudibranch Molluscs. Journal of Chemical Ecology. link.springer.com ↩
- Testing the Species Status of the Chromodorid Nudibranch Goniobranchus aureopurpureus (Mollusca: Gastropoda). researchgate.net ↩
- Reeflex.net — hobbyist/aquarium reference, used for the size measurement only (not peer-reviewed). reeflex.net ↩
-
A cute Sea slug - Chelidonura varians
https://youtu.be/7AbHSvaW4P4?si=7KZnRYyhfVjfB2BE
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nudibranch Ardeadoris egretta
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nori the Leaf Sheep Sea Slug takes a little ride! 🛵🌿
This tiny sea slug may live underwater, but apparently that doesn't mean he can't enjoy the freedom of two wheels.
A funny scooter-themed design for scooter lovers, motorcycle fans, riders, and anyone who enjoys a little weirdness with their ride.
Would you let Nori join you on your next ride?
#Scooter #ScooterLife #Motorcycle #MotorcycleLife #Biker #TwoWheels #FunnyShirt #SeaSlug #LeafSheep #tshirt #clothing #marinelife #graphic
-
Two Imperial Nudibranchs at an #Oahu #Hawaii #reef . Your #sealife #photooftheday
Prints available - DM me. #snail #seaslug #wednesday #creature #ocean #pacificocean #marinelife #animals #nature #wildlife #outdoors #explore #environment #earth #photo #photography #scuba #discover #underwater #art #critter #KeepItReal #C2PA
-
Meet the cutest DJ in the ocean!
Nori, the leaf sheep sea slug, is dropping fresh beats instead of leaves. If you love adorable sea creatures, music, and quirky designs, this one is for you.
#LeafSheep #LeafSheepSeaSlug #SeaSlug #Costasiella #CuteAnimals #OceanLife #MarineLife #SeaLife #DJ #MusicLover #CuteArt #Kawaii #CuteShirt #GraphicTee #TeeDesign #NatureLovers #OceanLovers #SeaCreature #FunnyShirt #GiftIdea -
Did you miss Nori, the part-time troublemaker leaf sheep sea slug? Well it's spa day today, scan the QR code, be like Nori. #spaday #SpaDayVibes #marinelife #seaslug #viralreels
-
Fat nudibranch varicosa
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Follow Nori, part sea slug, part leaf, full-time troublemaker. If you like cute sea creatures, wholesome humor, and simple cartoon adventures, you're in the right place. #marinelife #cuteanimals #seaslug #leafsheep #viral
-
Nudibranch - Phyllidia varicosa
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nudibranch - Glossodoris
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nudibranch Ardeadoris egretta
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Phyllidiella pustulosa nudibranch at an #Oahu #Hawaii #reef . Your #sealife #photooftheday
Prints available - DM me. #pink #seaslug #Friday #creature #ocean #pacificocean #marinelife #animals #nature #wildlife #outdoors #explore #environment #earth #photo #photography #scuba #discover #underwater #art #critter #KeepItReal #C2PA
-
Nudibranch - Nembrotha kubaryana
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nudibranch - Ardeadoris egretta
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Some nudibranchs and a flatworm
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #faltworm #ocean #sealife #marinelife #padi #seaslug #nudibranch
https://youtu.be/lVrpNlOiv-g?si=926G3inI--A2dujY -
Nudibranch Ardeadoris egretta
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
Nudibranch Ardeadoris egretta
#gili #giliislands #lombok #diving #scuba #trawangan #diveandstay #giliair #photo #ocean #sealife #marinelife #padi #seaslug #nudibranch -
These are gorgeous. And the jawdropping capability to separate out the venomous bits and transport them to the ramparts (metaphorically speaking) - wow!
https://crookedtimber.org/2026/04/28/occasional-paper-blue-angels-devil-hands/
-
Phyllodesmium briareum Mimicking Soft Coral on the Reef — Puerto Galera
Marine LifePhyllodesmium briareum — the Yellow-tipped Phyllodesmium — is a solar-powered aeolid nudibranch that mimics the soft coral it feeds on so precisely that most divers never see it. This individual was filmed moving through the reef in Puerto Galera, Philippines, at the northern edge of the Verde Island Passage.
Mimicry in Motion: The elongated cerata covering this animal are not coral polyps — they belong to a nudibranch. Phyllodesmium briareum mimics the briareid soft corals it feeds on so closely that the only reliable way to spot one is to notice that part of the coral is moving.
Phyllodesmium briareum — Species Identification
- Scientific NamePhyllodesmium briareum (Bergh, 1896)
- Common NameYellow-tipped Phyllodesmium
- ClassificationFamily Myrrhinidae — an aeolid nudibranch (Order Nudibranchia, Suborder Aeolidina)
- AppearanceTranslucent purple-grey body with elongated cerata bearing white or yellow tips; brown zooxanthellae visible through the tissue as rows of fine specks
- SizeUp to 25mm (~1″)
- DietCarnivore — feeds on briareid soft corals
- RangeTropical Indo-Pacific; Indonesia, Philippines, and Australia, typically reef-associated at 5–25m depth
Puerto Galera sits at the northern edge of the Verde Island Passage — one of the most biodiverse marine corridors on the planet — and the reefs here are rich in the soft corals that Phyllodesmium species depend on. Finding one is less a matter of looking for a nudibranch and more a matter of staring at a patch of soft coral long enough to notice that part of it is moving.
The genus name Phyllodesmium translates roughly to “leaf-like body,” and the species name briareum references Briareos — one of the hundred-handed giants of Greek mythology. It is an apt name for an animal covered in waving, arm-like cerata that match the size, shape, and posture of coral polyps so precisely that the animal disappears into its food source. The species was first described by Bergh in 1896 from specimens collected in Ambon, Indonesia, and has since been documented across the tropical western Pacific.
Solar-Powered Sea Slug: Unlike most nudibranchs, P. briareum harbors zooxanthellae — symbiotic algae harvested from the soft corals it eats. Rather than digesting these single-celled organisms, the nudibranch sequesters them in specialized ducts within its digestive gland, where they continue to photosynthesize and supply the animal with nutrients. It is, in effect, a nudibranch that runs partly on sunlight. According to research documented on the Sea Slug Forum, the zooxanthellae are visible as rows of brown specks through the animal’s translucent body wall — a useful field mark when trying to confirm genus-level identification underwater.
Autotomy Defense: If threatened, Phyllodesmium species can deliberately shed one or more cerata. The detached appendages continue to writhe on the substrate, drawing a predator’s attention while the animal crawls away. The cerata regenerate over time. This defense mechanism, combined with the animal’s near-perfect visual mimicry, makes P. briareum one of the more resilient small invertebrates on the reef — well-defended for something barely an inch long.
Filming Camouflaged Subjects: Close-focus macro work on a subject this well-camouflaged requires a deliberate search pattern and a slow approach. This was shot on the Panasonic GH5 with a 60mm macro lens in a Nauticam housing. The challenge is not the filming itself but the finding — and once found, holding position long enough to let the animal reveal its movement against the coral backdrop. The same patience applies to other cryptic marine life encounters — like filming a Ceratosoma trilobatum laying eggs in Lembeh Strait.
No artificial manipulation of the subject. The animal was filmed exactly as encountered on the reef.
Note on Identification: Phyllodesmium species are notoriously difficult to identify to species level in the field. This individual is tentatively identified as P. briareum based on cerata morphology and the soft coral substrate it was associated with. Over 20 species exist in the genus, and several overlap in range and appearance across the Philippines.