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Thuridilla lineolata

Thuridilla splendens


This is not a nudibranch, but it belongs to the same class (Gastropoda) as nudibranchs. Like nudibranchs, however, this sea slug has evolved out of its shell and uses bright colors to warn predators off. This species might be confused with its cousin, Thuridilla gracilis, due to similar coloration and patterns. T. lineolata grows bigger and does not "nod" its head when crawling, a behavior that T. gracilis is known for. All species of this genus eat algae.


This slug was in about 28m of water at a dive site called Marissa 1, off the western coast of Samal Island, Philippines. It measured about 2.5cm long and was crawling across the rubble in a fairly fast pace.

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mauna Kunzah
mauna Kunzah 9 years ago

I love sea slugs!

So colorful- fantastic creature!

Blogie 9 years ago

@ArgyBee - My very first spotting of a Thuridilla, the slug actually had those flaps partially open. Take a look:

Mark Ridgway
Mark Ridgway 9 years ago

What can I say Blogie - stunning creature and pics. Interesting about the parapodial flaps.

Blogie 9 years ago

Why thanks very much, AnnvanWijgerden! :)
Thank you too, Cyrill and dnl.grosso!

This type of slug can actually open up their dorsum, which has two flaps. Next time I'll try to take pictures of it with their flaps open.

AnnvanWijgerden 9 years ago

Great photography (as usual!) What a GORgeous creature!

Blogie 9 years ago

Thank you, jgorneau and NuwanChathuranga!

Jacob Gorneau
Jacob Gorneau 9 years ago

Amazing, Blogie!

Spotted by

Davao Del Norte, Philippines

Spotted on Jul 8, 2012
Submitted on Jul 8, 2012

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