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Blue Sea Slug

Glaucus marginatus

Notes:

We found these two tiny nudibranchs on our local beach this afternoon, washed up with a heap of bluebottles (Portuguese Man'O'War). Each is under a centimetre long, probably closer to 7-8mm. We scooped them up in a shell for these pics. These little creatures float upside down on the surface tension of the water. They are the only species in the genus Glaucilla, but are closely related to the larger (and showier) Glaucus atlanticus (http://en.wikipedia.org/wiki/Glaucus_atl...). Update 5/10/14 - This species appears to have been reclassified. I have updated the scientific name to Glaucus marginata accordingly.



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48 Comments (1–25)

HazelMarley
HazelMarley 3 years ago

I never knew those existed

hamzee413
hamzee413 4 years ago

Absolutely beautiful! They're like tiny dragons~

ShannaB
ShannaB 4 years ago

Thanks Neil. I got stung by a bluebottle once but it didn't affect me too badly - I think I was just lucky! Mostly, as a born and bred inlander, I just avoid bluebottle stings by staying well out of the water... ; ) I feel really lucky to have found these slugs when we did, I haven't seen them since... I'm desperate to find a Glaucus atlanticus too, but no luck. Actually that's what I was hoping to find the afternoon a couple of weeks ago when I came across that baby turtle!!!

Neil Ross
Neil Ross 4 years ago

Great series, Shanna. I'd forgotten all about these little beasties. So beautiful. Haven't seen one since I was a kid. These would wash up, and blue bottles weren't far behind. I always seemed to find the blue bottles whilst in the surf. Developed good immunity, I think. I was certainly stung enough.

RayTung
RayTung 5 years ago

Blue dragon! amazing shot!

ShannaB
ShannaB 5 years ago

They certainly are, Tic! : )

TicThapanya
TicThapanya 5 years ago

very beautiful organisms

Brian Muñiz
Brian Muñiz 6 years ago

I actually do, they look so similar to one another that their differentiation may have happened recently by evolutionary standards. They have the same blue coloration on the top to hide from predators from above and the silver below to hide from deepwater predators, and the fact that you mention the man o war is a great indicator that they are very similar, at least were I live there are some seasons where you cannot go to the water because man o war's arrive, as well as other deadly jellyfish and many that just hurt alot.

ShannaB
ShannaB 6 years ago

Thanks Scott. : )

ShannaB
ShannaB 6 years ago

Thank Gilma! Brian, thanks for the link. The info all seems to be about Glaucus atlanticus... there's hardly anything on Glaucilla marginata. Do you think the same info applies to both species? (Glaucilla marginata really seems to be the poor cousin!!)

Brian Muñiz
Brian Muñiz 6 years ago

Here's a link about their diet: http://en.m.wikipedia.org/wiki/Pelagic_s...

WOW!! Lovely!! Never seen them before. Great pictures.

ShannaB
ShannaB 6 years ago

It sure is, Dixie! : )

Dixie
Dixie 6 years ago

Amazing!

ShannaB
ShannaB 6 years ago

Thanks Jason, Braulio and Adarsha!

Adarsha B S
Adarsha B S 6 years ago

Wow ! what an amazing creation!

Just amazing!

Jason Alexander
Jason Alexander 6 years ago

Wonderful!

ShannaB
ShannaB 6 years ago

Haha Sheikanah, I see what you mean! But definitely not a fighting fish. : )

amazing creature, thought t'was a fighting fish.

ShannaB
ShannaB 6 years ago

Thanks Yuriana, Yuko, Ali, Holly, Yasser, Brian and Seema. Brian, I did read somewhere that they eat physalia and take their stinging cells but I couldn't find a reliable source!! (And we didn't know this when we found them... and we picked them up. Fortunately we didn't get stung!)

Seema
Seema 6 years ago

very unusual shape,,,,

Brian Muñiz
Brian Muñiz 6 years ago

Beautiful little guys, the pelagic sea slug actually feeds on the physalia or portuguese man o' war which is why you found them with it. They also take the stinging cells from the host for protection so I wouldn't touch them haha. Never seen one in person but they are interesting little nudibranches.

Yasser
Yasser 6 years ago

Gorgeous.

HollyCline
HollyCline 6 years ago

Cool

QLD, Australia

Lat: -26.55, Long: 153.10

Spotted on Jan 6, 2013
Submitted on Jan 6, 2013

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