Atagema osseosa
(Kelaart, 1859)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Family: Dorididae

DISTRIBUTION

Found throughout the tropical Indo-West Pacific.

PHOTO

Coffs Harbour Region, northern New South Wales, Australia, December 1990. PHOTO: Bill Rudman.

RELATED TOPIC

Defensive coloration in sea slugs

Formerly known as Trippa osseosa. See message

Atagema osseosa is an example of how many nudibranchs have evolved to perfectly match their surroundings. This species has the same colour and texture as the sandy sponge on which it lives and feeds. There are also a series of darker markings (patches without spicules) which match the oscula or waterholes in the sponge.

Reference:
• Kelaart, E.F. (1858). Description of new and little known species of Ceylon nudibranchiate molluscs and zoophytes. Journal of the Ceylon Branch of the Royal Asiatic Society,
Columbo, 3(1): 84-139.

Authorship details
Rudman, W.B., 1998 (October 14) Atagema osseosa (Kelaart, 1859). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/triposse

Related messages


Re: Atagema osseosa from sthn Queensland, Australia

September 11, 2006
From: Julie Marshall

Concerning message #15535:

Dear Bill,

Attached are a couple more images of Atagema osseosa. This animal was 10 mm in size and was found beneath a dead coral slab at the reef crest at Heron Island [Great Barrier Reef] at low tide.

Locality: Heron Island, Intertidal, Queensland, Australia, Pacific, 15 November 2001, Intertidal. Length: 10 mm. Photographer: Julie Marshall.

Best wishes
Julie Marshall

juliemarshall@netspace.net.au

Marshall, J.G., 2006 (Sep 11) Re: Atagema osseosa from sthn Queensland, Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/17436

Thanks Julie,
Juveniles like this are very good at showing how the spicules in the mantle wall form a radiating network within the mantle tissue, creating a skeletal framework for both the tubercles and the mantle wall.

Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Sep 11). Comment on Re: Atagema osseosa from sthn Queensland, Australia by Julie Marshall. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/17436

Atagema osseosa from sthn Queensland, Australia

August 9, 2006
From: Gary Cobb

Hi Bill!
In January, I went to Alex Headland and turned over some rocks and found this beautiful little dorid. I think it is Atagema osseosa. When I initially found it I thought it was a lamellariid. I collected it and while it was crawling I knew it was a dorid.

Locality: Alexandra Headland, sthn Queensland Australia. Locality: Depth: intertidal. Length: 24 mm.11 January 2006. Photographer: Gary Cobb

Cheers,
Gary Cobb

gary@nudibranch.com.au

Cobb, G., 2006 (Aug 9) Atagema osseosa from sthn Queensland, Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15535

Dear Gary,

Thanks for the nice photos. They show the tubercles, with a crown of spicules around the tip, very well. For those of you not familiar with the term, these tubercles are known as caryophyllidia.

Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Aug 9). Comment on Atagema osseosa from sthn Queensland, Australia by Gary Cobb. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15535