Hallaxa indecora
(Bergh, 1905)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Family: Actinocyclidae

DISTRIBUTION

Indo-West Pacific

PHOTO

Kerama Island, near Okinawa PHOTO: Mr Atsushi Ono. See Rie Nakano's message below.

Living animal described by Gosliner & Johnson as light plum in colour. General shape ovoid with a smooth mantle. The rhinophores and gills are the same colour as the mantle.

Reference:
• Gosliner, T.M. & Johnson, S. 1994. Review of the genus Hallaxa (Nudibranchia: Actinocyclidae) with descriptions of nine new species. The Veliger, 37(2):155-191.

Authorship details
Rudman, W.B., 1999 (April 20) Hallaxa indecora (Bergh, 1905). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/hallinde

Related messages


Re: Hallaxa indecora from American Samoa

September 16, 2003
From: Terry Gosliner

Hi Bill,
I am fairly certain that Don Barclay's photos are of H. indecora. It has a really thin, translucent skin, while that of H. cryptica is thicky and more rubbery. H. indecora is also more elongate and slender while H. cryptica tends to be flatter and more ovoid.
Terry.

tgosliner@calacademy.org

Thanks Terry,
Bill Rudman

Hallaxa indecora? from American Samoa

September 13, 2003
From: Don Barclay


Hello Bill,
While attempting to sort my Samoan photos, I came across this one that I had never gotten around to identifying. It looks to be Hallaxa indecora, although it has quite a few white specks on the mantle, particularly around the margins and a ring of white specks around the base of the rhinophores. I don't see any white on Atsushi's animal, but it seems to be otherwise identical. There appear to be a few scattered spots on Bernard Picton's animal.

I found this one on my last snorkeling trip in Samoa, a few meters from where the Chromodoris albonares was found, about 1700 local time on 25 August 2001. It was on the edge of a dead coral slab in less than one meter of water, ~200 meters west of Onesosopo Point, east Pago Pago Harbor, American Samoa. It measured about 15mm, until it had been in the aquarium a couple of hours, when it flattened and stretched to around 20mm.

The body on this animal was fairly stiff, and it was the slowest-moving true nudibranch I've ever observed.
Cheers,
Don

barclay@txucom.net

Barclay, D., 2003 (Sep 13) Hallaxa indecora? from American Samoa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10412

Thanks Don,
I am afraid I have trouble with some of these species of Hallaxa. I agree from the bulbous rhinophores and 'cup-shaped' gill circlet that this is most probably a species of Hallaxa, but I can't say much more. As you suggest, it has similarities to Hallaxa indecora, but it also has similarities to the dark form of Hallaxa cryptica. Perhaps Terry Gosliner can help us out. I have put another photo of this animal in a separate message.
Best wishes,
Bill Rudman

Rudman, W.B., 2003 (Sep 13). Comment on Hallaxa indecora? from American Samoa by Don Barclay. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10412

Hallaxa indecora? from American Samoa (2)

September 13, 2003
From: Don Barclay

Bill,
Here's another photo of the Hallaxa
Don Barclay

barclay@txucom.net

Barclay, D., 2003 (Sep 13) Hallaxa indecora? from American Samoa (2). [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10413

Hallaxa indecora from Hong Kong

May 8, 2002
From: Bernard Picton


Hi Bill,
I think these pictures are of Hallaxa indecora. One animal was collected during the workshop in Hong Kong in 1983.

19 Apr 1983 - Breakers Reef, Mirs Bay, Hong Kong. Photo: B.E.Picton.

Bernard

bernard.picton.um@nics.gov.uk

Picton, B. , 2002 (May 8) Hallaxa indecora from Hong Kong. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5949

Thanks Bernard,
Bill Rudman

Hallaxa? from Kerama Islands

April 20, 1999
From: Rie Nakano

Dear Bill,

Here is another of Mr Atsushi Ono's images from Kerama Island, near Okinawa which you offered to identify for us.

Mr.Bob Bolland and Mr.Ono think it is Hallaxa indecora, but Mr.Cory Pittman said the genus Hallaxa contains typical cryptobranch dorids while the animal in the photo looks more like a juvenile
phanerobranch dorid (of uncertain identity).

Rie Nakano

rie@street.ne.jp

Nakano, R., 1999 (Apr 20) Hallaxa? from Kerama Islands. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/782

It is a bit hard to be sure, but it could be Hallaxa indecora, the tightly arranged gills being quite characteristic of Hallaxa.

Best wishes,
Bill Rudman.

Rudman, W.B., 1999 (Apr 20). Comment on Hallaxa? from Kerama Islands by Rie Nakano. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/782

Re: Hallaxa indecora from Kerama Ids

April 20, 1999
From: Terry Gosliner

Dear Bill,
The animal from Kerama Island looks identical to the specimens that Bob Bolland sent me from Okinawa. We examined the internal anatomy of these specimens and identified them as Hallaxa indecora in the paper I did with Scott Johnson.

Terry

tgosliner@casnotes1.calacademy.org

Gosliner, T., 1999 (Apr 20) Re: Hallaxa indecora from Kerama Ids. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/795

Terry,
Thanks for the quick response!
Bill

[The paper is: Gosliner, T.M.; Johnson, S. 1994. Review of the genus Hallaxa (Nudibranchia: Actinocyclidae) with descriptions of nine new species. Veliger 37(2):155-191.

Rudman, W.B., 1999 (Apr 20). Comment on Re: Hallaxa indecora from Kerama Ids by Terry Gosliner. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/795