Glaucilla marginata
Bergh, 1860

Order: NUDIBRANCHIA
Suborder: AEOLIDINA
Family: Glaucidae

DISTRIBUTION

Circumglobal in temperate and tropical waters.

PHOTO

Collaroy Beach, Sydney, New South Wales. February 1987. 35mm long alive. Photographed from above to show foot - both Glaucilla and Glaucus float upside down.
PHOTO: Bill Rudman.

RELATED TOPIC

Glaucus atlanticus

Both Glaucus and Glaucilla appear to be "monotypic" genera. That is each genus has only one species. The main external difference is that in Glaucus the cerata are arranged in a single row in each arch while in Glaucilla there are multiple rows. The biology of the two species is discussed under Glaucus atlanticus.

See photos of pelagic egg strings.

Reference:
• Bergh, L.S.R. (1860). Om Forekomsten af Neldefiim hos Mollusker. Vidensk. Meddel. Naturh. Foren. Kj√∂benhavn, p. 309-331, pl. 8

Authorship details
Rudman, W.B., 1998 (November 6) Glaucilla marginata Bergh, 1860. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/glaumarg

Related messages


Glaucilla marginata from sthn Queensland

February 13, 2009
From: Gary Cobb


Concerning message #22156:

Hi Bill and everyone!
This time the topic is Glaucilla marginata. There are not very many entries for this little beauty, so here we go.

This species is quite common along the beaches after a big onshore wind. They are typically quite small compared to Glaucus atlanticus. I have included a great frontal shot clearly showing the multi-layered cerata [upper photo]; a photo comparing size of large G. atlanticus and small G. marginata [middle photo]; and a mating pair [lower photo]. During the mating I was quite amazed at the actual size on the sexual organ. Nearly the length of the 'arm'. My guess is that with a short organ would not reach because of the size of the 'arm'.

Locality: Mooloolaba, Sunshine Coast, stranded on beach, Queensland, Australia, Pacific Ocean, 20 January 2009, Pelagic. Length: 5-17 mm. Photographer: Gary Cobb.

Cheers
Gary

gary@nudibranch.com.au

Cobb, G.C., 2009 (Feb 13) Glaucilla marginata from sthn Queensland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22167

Dear Gary,

Thanks for this great set of photos. Glaucilla marginata is often overlooked when found with the much larger Glaucus atlanticus. Both species have extremely large copulatory organs and your suggestion that it is because they can't get close together is eminently reasonable. I think Charles Darwin - whose 200th birthday we are celebrating at present - was the first to note the extremely long penis of the humble barnacle - proportionally the longest in the animal kingdom - an adaptation for an animal permanently stuck on a rock. A long penis is their way of getting 'close together'.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Feb 13). Comment on Glaucilla marginata from sthn Queensland by Gary Cobb. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22167

Re: Tiny, elaborate creature at Stradbroke Island, Queenslan

January 20, 2009
From: Rob Blackmore

Concerning message #21205:

Hi there, I have just discovered many similar creatures at Mount Coolum beach on the Sunshine Coast today. I think they are probably more likely to be Glaucilla marginata? a close relative of Glaucus atlanticus.

Locality: Mount Coolum beach, Beach, Queensland, Pacific Ocean, 15 Jan 2009, Inter-Tidal beach. Length: 7 mm. Photographer: Rob Blackmore.

Regards,
Rob

rhblackmore@mac.com

Blackmore, R.H., 2009 (Jan 20) Re: Tiny, elaborate creature at Stradbroke Island, Queenslan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22156

Thanks Robert,

Yes this is Glaucilla. On reflection, Ken Thomas's animal - which your refer to - could well be Glaucilla marginata rather than Glaucus, but its a bit hard to be sure from the photo.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Jan 20). Comment on Re: Tiny, elaborate creature at Stradbroke Island, Queenslan by Rob Blackmore. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22156

Re: Nematocysts in Glaucilla

January 21, 2001
From: Julia Busch

Dear Bill,
Thank you for answering my question quite fast!! I am preparing an oral presentation and had a lack of information. Yes, I am, too, interested in the research, maybe it is possible in the next years or after my marine biology study.
Julia.

tronic78@gmx.de

Busch, J., 2001 (Jan 21) Re: Nematocysts in Glaucilla. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3577

Nematocysts in Glaucilla

January 20, 2001
From: Julia Busch

Is there any actual research about Glaucilla's utilization of nematocysts?
Julia Busch

tronic78@gmx.de

Busch, J., 2001 (Jan 20) Nematocysts in Glaucilla. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3568

Dear Julia,
Although Glaucus atlanticus and Glaucilla marginata are in separate genera, this is probably an unnecessary inflation of their taxonomic rank. In anatomy and natural history they are very close and probbaly should be in a single genus. To my knowledge there are only the two papers by Thompson & Bennett which study the nematocysts found in the cnidosacs of these two species, and they identified them as belonging to Physalia and Porpita. They also showed that the nudibranchs accumulate the largest, most penetrating, nematocysts from their prey. The references are on the Glaucus atlanticus Page.

Is your interest general, or are you undertaking some research on these fascinating animals?
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Jan 20). Comment on Nematocysts in Glaucilla by Julia Busch. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3568

Glaucilla marginata - any east Pacific records?

January 29, 2000
From: Orso Angulo

Hi Bill
I wonder if you or any of the brancher that visit your site could help me. I'm searching for information regarding reported localities of G. marginata on the Pacific coast of North America (if there are any).

Thanks
Orso Angulo

Allende #1245 E/Felix Ortega e Isabel la Catolica
Col. Centro
C.P. 23000
La Paz, B.C.S.
Mexico

mol@lapaz.cromwell.com.mx

Angulo, O., 2000 (Jan 29) Glaucilla marginata - any east Pacific records?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1814