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Blue dragon

Pteraeolidia ianthina


Is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae. 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. 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. 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.


Found in diverse habitats and among shallow coral reefs throughout Southwestern Pacific Ocean, from Hawaii to the Philippines, to the Northeast Australian waters and New Zealand.


Blue dragon name comes from its ressemblance to the Chinese Dragon.

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The MnMs
The MnMs 8 years ago

Thanks Darthviasco,
These exist in many colors. you should come to Philippines to spot them :-)

Darthviasco 8 years ago

That is great. I knew a little about the little nudibranches just not this one. :)

The MnMs
Spotted by
The MnMs

Negros Oriental, Philippines

Spotted on Nov 3, 2012
Submitted on Nov 3, 2012

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