Okenia brunneomaculata
Gosliner, 2004
Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: ANADORIDOIDEA
Family: Goniodorididae
DISTRIBUTION
Known only from Luzon Island, Philippines and Bali, Indonesia
PHOTO
Upper: Luzon, Philippines. Photo: T.M.Gosliner. Lower: SEM of radula showing inner lateral tooth (right) and two outer lateral teeth (left). Scale bar = 2 µm. [Photos from Gosliner, 2004 with permission].
The body is a uniform translucent white, with a chocolate brown band down each side of the body and irregular spots of the same color scattered over the mantle. Along the mantle edge on each side are five or six elongate lateral papillae, the two anterior-most papillae on each side are situated in front of the rhinophores and are anteriorly directed. There are also four to seven elongate papillae scattered mid-dorsally in front of the gills and there is a single median papilla immediately behind the gills. The oral tentacles are elongate and extend well beyond the margin of the foot. The largest animals so far reported are between 4-6 mm in length. It has been found on ctenostomatous bryozoans on the undersides of the large foliose sponge colonies.
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Gosliner, T. M. (2004) Phylogenetic Systematics of Okenia, Sakishimaia, Hopkinsiella and Hopkinsia (Nudibranchia: Goniodorididae) with descriptions of new species from the tropical Indo-Pacific. Proceedings of the California Academy of Sciences, 55: 125-161.
Rudman, W.B., 2004 (December 21) Okenia brunneomaculata Gosliner, 2004. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/okenbrun
Related messages
Okenia brunneomaculata from sthn Queensland
June 10, 2009
From: Gary Cobb
Concerning message #15875:
Hi Bill and everyone!
The recent big seas and heavy rain that produced massive amounts of debris in the resulting run-off had prevented us from venturing out across Moreton Bay to the outside reefs. Last Friday and Saturday however gave us our first opportunity in 3 weeks to do so and we examined a very small leeward section of Flinders Reef over a 2 day period.
Close examination of the fronds of an algae plant believed to be Lobophora variegata growing under the overhang of a small bommie revealed what at first appeared to the naked eye to be a tiny white anemone not unlike the ones preyed upon by Baeolidia spp. However, reviewing the magnified photos via the camera playback screen revealed a 5 mm long species of Okenia. Further photos were then taken underwater upon our black slate for contrast and in the perspex bowl for side shots.
Comparing the images with those in various books and the Forum has led us to believe we have found Okenia brunneomaculata, being a new record for Australia. This has been confirmed for us by Richard Willan.
We could not discern any growth on the algae frond that it may have been feeding upon and therefore deduce it must have been in transit.
Locality: Flinders Reef, Moreton Island, 16 m, Queensland, Australia, Pacific Ocean, 06 June 2009, Subtidal. Length: 5 mm. Photographer: David Mullins.
Cheers Gary & David
nudibranch.com.au
gary@nudibranch.com.au
Dear Gary & David,
An interesting find. We have a record from East Timor so one from southeastern Queensland certainly suggests this may be a widespread tropical species - at least in the western Pacific and probably in the Indian Ocean as well.
Best wishes,
Bill Rudman
Re: Okenia brunneomaculata from East Timor
February 18, 2006
From: Francis & Pirjo Pellet
Concerning message #15831:
Hi Bill,
We found this one last year in Lembeh-Strait : we think it is the same animal as in Brian Francisco photos. We found it on a coral reef but we don't know if our pictures give you more information of its feeding habit.
Locality: Coral Garden, 15 m, North Sulawesi , Indonesia, Indian Ocean, South China sea, 08 October 2005, Coral. Length: 5 mm. Photographer: Francis & Pirjo Pellet,
Best Regards
Francis & Pirjo Pellet
pirjo.pellet@free.fr
Dear Francis & Pirjo,
Yes this is Okenia brunneomaculata. I'm afraid it doesn't tell us any more about its feeding, but at this stage in our knowledge of the species, every new record is useful. For example, the lower left photo shows the lamellae on the rhinophores very well.
Best wishes,
Bill Rudman
Okenia brunneomaculata from East Timor
February 16, 2006
From: Brian Francisco
Hi Bill,
Here are a few photos of Okenia brunneomaculata to add to your collection. This individual was 5mm and found on coral rubble at 17 meters.
Locality: Dili Rock, 17 meters, East Timor, Banda Sea, 12 February 2006, coral rubble. Length: 5 mm. Photographer: Brian Francisco
Regards
Brian
francisco.brian@gmail.com
Dear Brian,
This is to my knowledge the first record of the species since it was described. We suspect most species of Okenia are bryozoan feeders, but for most of them we have no feeding observations, and in fact we know little about their biology. I can't really make out what the 'feathery' animals are that the Okenia is crawling over [see lower left close-up]. I thought perhaps they were some solitary bryozoan but they could be a variety of things - and even if we identified them, there is no evidence they are its food. If you come across this species again, or any species of Okenia for that matter, observations, or even clues to possible food, are always welcome.
Best wishes,
Bill Rudman
