This nudibranch is easily recognised by the overall pink-purple coloration of the body and processes. Opaque white pigment is present on the extremities and as white rings at the tips of the cerata. The digestive gland is usually red in colour, partly masked by the purple hue. Typically about 20mm in length. Structurally similar to other Flabellinids, but distinguished by its purple hue. Flabellina affinis shares this coloration, but has lamellate rhinophores and more pedunculate cerata and is found in the Mediterranean Sea, but not further north.
When you’re four centimeters long and soft-bodied, you have to protect yourself somehow. Nudibranchs or sea slugs, like many soft marine animals, employ a lot of visual and chemical defenses. Bright colors can work a couple of different ways: if they are the same color as the coral or whatever you are sitting on, they help you blend in and avoid detection. In other cases, bright, visible coloring warns predators that you contain noxious or toxic chemicals. Which is often the case if, like this individual, you feed on hydroids.
DEEP SEA MONSTER FOUND BY RESEARCHERS IN CAROLINE ISLANDS WATERS!
by Vic Smith - Project Lab
Is this a fantasy, or could it be true?This bogus headline describes a real event that took place in 2005, when Lori Bell and Pat Colin of the Coral Reef Research Foundation were diving off of Palau in the Caroline Islands using the Deep Worker Submarine.While working at depths between five hundred seventy and six hundred seventy feet they encountered and collected 2 specimens of an apparently unknown species of nudibranch.
While the majority of nudibranchs are relatively small, (less than an inch to a couple of inches), this bright-red monster was over four inches long, and sported a veritable forest of branched tentacles (branchial plumes) used to increase surface area for‘breathing’. Nudibranchs have been collected by divers to a depth of about two hundred fifty feet, and at far greater depths by dredging from boats, but a collection from this depth was very unusual…
Four new species of splanchnotrophid copepods (Poecilostomatoida) parasitic on doridacean nudibranchs (Gastropoda, Opistobranchia) from Japan, with proposition of one new genus 
Four new species of splanchnotrophid copepods are described based on specimens collected from 5 species of doridacean nudibranchs from coastal waters of Japan.
They belong to 3 genera, one of which, Majimun gen. n., is new. The parasites and their hosts are as follows: Ceratosomicola japonica sp. n. ex Hypselodoris festiva; Splanchnotrophus helianthus sp. n. ex Thecacera pennigera; S. imagawai sp. n. ex Trapania miltabrancha; and Majimun shirakawai gen. et sp. n. ex Roboastra luteolineata and R. gracilis. Ceratosomicola japonica sp. n. is the fifth species of Ceratosomicola and is characterized by the shape and armature of the prosome in females.
Both S. helianthus sp. n. and S. imagawai sp. n. are differentiated from 4 known congeners by the absence of posterolateral processes or lobes on the prosome in females, and the females of these 2 new species are separated from each other by the shape and armature of the genito-abdomen, the mandible, and the swimming legs. Majimun gen. n. is distinguished from other splanchnotrophid genera by the segmentation of the antennule as well as the combination of the following characters in females: 2 postgenital somites and the shape of the antenna, the mandible and the swimming legs.
Blue Ocean Slug (Glaucus atlanticus) - “The Blue Dragon”
Photograph by Daniel Coleman, My Shot
The blue ocean slug, a type of nudibranch, is a striking specimen with extraordinary hues that provide two types of camouflage. On the sea surface, the animal’s blue topside provides protection from hungry birds above, while its silver subsurface hides it from predatory fish looking up from below.
The blue ocean slug is itself a formidable predator that feasts on dangerous animals like the Portuguese man-of-war. Not only is the slug unfazed by the man-of-war’s stinging cells, it ingests them and transports the toxic weapons internally to the ends of its own appendages for self-defense.
….is a species of nudibranch found throughout the Mediterranean sea and eastern Atlantic. T.fimbria is a hunter and combs the ocean floor for small crustaceans, scooping them up in its large hood. Although they are often found in the sand, these nudibranchs are also accomplished swimmers and can often be seen swimming in the water column.
Hero formosa is found in relatively shallow waters in the UK and Europe, most recently from the west coast of Scotland. Not the most remote marine habitat for curious humans; still, this species is relatively scarce, so there’s a lot we don’t know about it, like, for instance, what it eats. It is often found on or near hydroids, which are considered tasty by many other nudibranchs, so that’s a possibility. It’ll probably take a few more careful, and lucky, dives to find out for sure.
Sea slug loses penis after sex but grows another the next day
Invertebrate may discard organ like a dirty needle to avoid carrying competitors’ sperm.
by Matt Kaplan
The astounding warning colours of the nudibranchs, a diverse group of sea slugs, are certainly enough to attract attention — but even they pale in comparison to the gripping news that one species of the soft-bodied molluscs has a habit of discarding its penis.
Nudibranchs are hermaphrodites, meaning that they carry both male and female reproductive organs. Moreover, when they mate, they can perform the male role of donating sperm and the female role of receiving sperm at the same time. This process involves two penises and two vagina-like organs, and sperm transmission effectively happens simultaneously during the encounter.
This is a relatively standard arrangement among nudibranchs, so the creatures’ sexual organs might all be expected to look roughly the same. But the animals show incredible sex-organ diversity, and it was during an exploration of this diversity in the species Chromodoris reticulata that researchers made their jaw-dropping discovery…
is a species of aeolid nudibranch native to the west coast of North America, parts of central america and the Galapagos. The Spanish shawl is easily recognizable due to its stunning purple and orange coloration, these bright colors serve as warnings to potential predators that the cerata (orange appendages) are filled with dangerous stinging cells stolen from the cnidarians that they prey on.
is a species of dorid nudibranch found in Indo-pacific waters from Japan to Australia. like alot of nudibranchs they are fairly small only growing up to 5 inches long. They are best known for their bright yellow color with a series of black lines covering their body. A. minor feeds mostly on species of calcareous sponge of the family Lecuettidea but will eat other species as-well.
Is a species of nudibranch of the family Tethydidae, this species can be found on the west coast of North America, from Alaska all the way to Baja California. The name hooded comes from the large oral hood that the animal possess, this hood is filled with sensory tentacles and the animal can open and throw said hood forward in order to catch food. when removed from the water they exude a sweet fruit like oder