Blue dragon nudibranch (Pteraeolidia ianthina)
Photo by Loh Kok Sheng
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Blue dragon nudibranch (Pteraeolidia ianthina)
Photo by Loh Kok Sheng
Serpent Pteraeolidia | Pteraeolidia ianthina
The incredible blue dragon nudibranch, Pteraeolidia semperi. I have been wanting to see this nudibranch for years and last summer I FINALLY found one on a dive in Kauai. I was overjoyed. It was more beautiful than I could have ever imagined! And maybe one of the only blue nudis I’ve ever seen.
Koloa Landing
Kauai, Summer 2018
Quiet bokeh blues
Bowie :: Nudi
IMG_5891 Pteraeolidia ianthina by budak Via Flickr: blue dragon nudibranch
The curiosities of the Blue dragon nudibranch
Commonly referred to as the Blue dragon nudibranch, Pteraeolidia ianthina (Nudibranchia - Facelinidae), is a remarkable species of sea slug native to the Indo-Pacific region.
This is an extremely elongate species up to 5cm long, with large, curved arches of cerata (the projections on the upper surfaces of the body) along the length of the body. The cephalic tentacles have two distinctive dark purple (or blue) bands.
Although the body color of this nudibranch is translucent tan, the cerata, which are mostly blue or dark purple, lavender or golden brown, give the nudibranch most of its apparent color.
The Blue dragon nudibranch has many amazing survival strategies. When touched, the nudibranch will "flare" its cerata and the nematocysts will discharge on contact (it is one of the few nudibranchs with a sting strong enough to be felt by humans though usually not in areas with thicker skin such as the palm of the hand).
It is also able to autotomize (lose or detach) the posterior part of its body in order to distract, or free itself from, a potential predator. Later, the missing portion can be regenerated.
Another curiosity of this species is that the cerata contain zooxanthellae of the genus Symbiodinium that exhibit the capacity for photosynthesis, and they grow while reside in the sea slug. This symbiotic relationship with the algae helps the adult nudibranch to overcome a period of food shortage by getting photosynthetic products.
References: [1] - [2] - [3] - [4]
Photo credit: ©Sylke Rohrlach
Locality: New South Wales, Australia
Pteraeolidia ianthina - Anilao, Philippines | ©Carlos Fernandez-Cid
Pteraeolidia ianthina, commonly known as the ‘Blue Dragon’, is one of a group of remarkable aeolid nudibranchs which are way ahead of man in harnessing solar energy.
This nudibranch has evolved a method of capturing and farming microscopic plants (zooxanthellae) in its own body. The plants flourish in this protected environment and as they convert the sun’s energy into sugars, they pass a significant proportion on to the nudibranch for its own use.
White animals are juveniles which as not yet developed their crop of zooxanthellae. If this species is similar to others that have been studied then they must obtain its first “injection” of zooxanthellae by feeding on a hydroid with symbiotic zooxanthellae. White juveniles are usually found in lush growths of short “turfing” hydroids, but until now no sign of zooxanthellae has been found in the hydroids.
Adults can last some time without feeding, presumably obtaining sufficient nourishment from their zooxanthellae gardens. The large solitary hydroid is the preferred adult food.
[Source and more information]
The sea dragon slug (Pteraeolidia ianthina): steals stinging cells and photosynthetic symbionts from its prey -- while looking super fancy!
http://en.wikipedia.org/wiki/Pteraeolidia_ianthina
"Pteraeolidia ianthina, one of the most common aeolids found, is often called a "blue dragon" by Eastern Australian divers because of its close resemblance to a Chinese dragon.[4] It is one of the most common aeolid nudibranchs found in Eastern Australia. It can inflict a painful sting to humans.
The slug is very elongated (7 cm) with many clusters of medium-large sized cerata along the length of the body. The fat rhinophores and the long cephalic tentacles have at least two dark purple bands that stand out. The tips of the cerata contain nematocysts.
Symbiotic zooxanthellae continue to photosynthesise inside the body and give rise to brown and green pigments. The zooxanthellae, together with the nematocysts, are presumed to be derived from coelenterate prey. These zooxanthellae occur within vacuoles in host cells derived from the endoderm.[5]"
"This sea slug has evolved the ability to harness the sun's energy for its own use. This is possible because the slug feeds on hydroids which contain symbiotic zooxanthellae, microscopic dinoflagellates that are photosynthetic — in other words that have the capability to make sugars from sunshine. The nudibranch farms these zooxanthellae within its own digestive diverticula. The zooxanthellae then convert the sun's energy into sugars. The sugars are used by the slug.[7]"
Image 1: Blue Dragon - Pteraeolidia ianthina
Tooth Brush Island. Flickr user billunder, 2009: http://www.flickriver.com/photos/12499727@N04/4230026282/
Image 2: Blue Dragon - Pteraeolidia ianthina
Flickr user billunder, Australia, 2009: http://www.flickriver.com/photos/12499727@N04/4232772648/
Blue Dragon - Pteraeolidia ianthina
Image 3: Sea dragon slug (Pteraeolidia ianthina), GBR, Australia
Photo by Arthur Anker: http://www.flickr.com/photos/artour_a/3385581613/in/set-72157623477677107