Marionia olivacea
Baba, 1937
Order: NUDIBRANCHIA
Suborder: DENDRONOTINA
Family: Tritoniidae
PHOTO
Toyama Bay, The Japan Sea, 30-50m, 13-24 July 2002, from a fishing net. Photos: Shigeru Hayashi
In both of Baba's descriptions (1937, 1949) he notes the colour as being 'generally olive in colour' so these photos give us a much better idea of this species' colours. They match one of the illustrations in Baba, 1949 (Pl.34, fig. 126) very well. The animal is a translucent cream with a pattern of dark brown and orange brown. The sides of the body are pustulose with a network of orange brown running between the pustules. The mantle and oral veil are essentially orange brown with a symmetrical pattern of dark brown patches along the edge of the mantle and at the base of the gills. It grows to 80mm.
Bergh (1905) described a species Tritonia olivacea from Indonesia. It is possibly congeneric with Baba's species, but until it is rediscovered and examined we can't say whether these 2 species are homonyms.
Reference:
• Baba, K. (1937) A New Species of the nudibranchiate genus Marionia from Sagami Bay, Japan. Venus, Jap. Jour. Malac., 7(3): 115-120.
• Baba, K. (1949) Opisthobranchia of Sagami Bay, collected by His Majesty Emperor of Japan. Iwatani Shoten, Tokyo, 86-87.
Rudman, W.B., 2002 (December 2) Marionia olivacea Baba, 1937. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/marioliv
Related messages
Marionia olivacea? from Sulawesi
December 16, 2002
From: Mary Jane Adams
Hi Bill,
I photographed a slug in Indonesia last week that looks a lot like Marionia olivacea. It was sitting on a sand slope in Lembeh Strait, Sulawesi.
Divesite: Hairball Too
Depth: 8 meters,
Length: 25mm,
Date: Nov. 25, 2002 about an hour after dark.
What do you think?
Best regards,
Mary Jane
divepng@yahoo.com
Adams, MJ., 2002 (Dec 16) Marionia olivacea? from Sulawesi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/8613Thanks Mary Jane,
It could well be. At present we don't know enough about colour variation in the tritoniids to be very sure of most species in the Indo-West Pacific. I had thought of M. olivacea as a probable NW Pacific endemic, but we really don't know enough about its distribution.
Best wishes,
Bill Rudman
Marionia olivacea from the Japan Sea
December 4, 2002
From: Shigeru Hayashi
Dear Bill,
Here are some photos of Marionia olivacea which was promised before.
It was collected from a fishing net with 30 - 50 meter depth. Those individuals were provided by The Notojima Aquarium.
Data: Toyama Bay, The Japan Sea, 30-50m, July, 13-24. 2002
I think M. olivacea resembles the Atlantic species M. blainvillea.
Reference:
• Baba, K. (1937) A New Species of the nudibranchiate genus Marionia from Sagami Bay, Japan. Venus, Jap. Jour. Malac., 7(3): 115-120.
• Baba, K. (1949) Opisthobranchia of Sagami Bay, collected by His Majesty Emperor of Japan. Iwatani Shoten, Tokyo, 86-87.
Yours Sincerely,
Shigeru Hayashi (Takaoka Biological Club)
jr9dsx@tko.fitweb.or.jp
Dear Shigeru,
Thanks for this addition to the Forum. In both of Baba's description he notes the colour as being 'generally olive in colour' so these photos give us a much better idea of this species' colours. Your photos fit one of the illustrations in Baba, 1949 (Pl.34, fig. 126) very well.
Best wishes,
Bill Rudman
