Cratena lineata
(Eliot, 1905)

Family: Glaucidae


Tropical Indo-West Pacific.


UPPER: Woolgoolga, nthn New South Wales, August 1991, 12mm long. LOWER LEFT: Eden, southern New South Wales, February 1983, 10mm long. LOWER RIGHT: Southern Yorke Peninsula, South Australia, February 1985, 18mm long. PHOTOS: Bill Rudman.

This species usually has white longitudinal lines on the body and cerata. Sometimes the lines on the cerata are restricted to the tip and sometimes the body can lack any pigmentation. The digestive gland duct in each ceras ranges in colour from bright red, green or dull brown to black. Often the basal section of the ceratal digestive gland duct is red, and the rest a brownish colour, perhaps reflecting a change in diet. Normally there is one large orange patch on each side of the head but in some specimens this can be replaced by a bent line or divided into two spots on each side.

This is one of two similarly coloured species described by Eliot (1905). The lower right photo from sthn Yorke Peninsula is identical in colour to Hervia lineata [Pl. XVI fig. 2.], The second species, Facelina lineata is also illustrated on Plate XVI, in fig 4.

  • Edmunds, M. (1970). Opisthobranchiate Mollusca from Tanzania. II. Eolidacea (Cuthonidae, Piseinotecidae and Facelinidae). Proceedings of the Malacological Society of London 39: 15-57.
  • Eliot, C.N.E. (1905). On some nudibranchs from east Africa and Zanzibar. Part VI. Proceedings of the Zoological Society of London, 1904(2): 268-298, Pls. 16-17.

Authorship details
Rudman, W.B., 2000 (March 13) Cratena lineata (Eliot, 1905). [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

Cratena lineata? from Poor Knights Islands

February 27, 2008
From: Ian Skipworth

Hi Bill

This is new one for me which I found the weekend before last.

Locality: Poor Knights Islands, 15 m, New Zealand, Pacific Ocean, 18 November 2007, Rocky reef. Length: 12 mm. Photographer: Ian Skipworth.

Any advice you can provide as to its identification would be much appreciated.


Skipworth, I.R., 2008 (Feb 27) Cratena lineata? from Poor Knights Islands. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Ian,

This looks quite like the tropical Indo-West Pacific species Cratena lineata in colour, but the arrangement of the ceratal groups make me hesitate. I am afraid this is one of those times when I think a photo is not enough.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Feb 27). Comment on Cratena lineata? from Poor Knights Islands by Ian Skipworth. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Cratena lineata?

February 14, 2002
From: Rie Nakano

Dear Dr.Rudman,
I found this Cratena at the edge of the rocky reef of Hachijo Island, Izu, Japan, in 28th, September, 2001.
At first,I thought this animal was Cratena lineata. But the background of this animal has no white lines. Is this Cratena lineata?

Depth: 15m
Length: 20mm
Water temperature: 24.3 degrees
Frequency: uncommon in Hachijo

Rie Nakano

Nakano, R., 2002 (Feb 14) Cratena lineata?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Rie,
Yes this is Cratena lineata, If you look at some of my photos on this page you will see that sometimes the white lines can be absent from the cerata as well.
Best wishes,
Bill Rudman.

Rudman,W.B., 2002 (Feb 14). Comment on Cratena lineata? by Rie Nakano . [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Cratena lineata from SE Sulawesi

March 23, 2000
From: Lindsay Warren

Dear Bill
Attached are two photos of another aeolid (OWN87) I found at 7.45am on 11 May 1999 at a depth of 60 ft.  Size:  6-8 mm.  It was on a polypropylene mooring line set some distance from the reef which had only been in the
water for two months.  However there was a good covering of small hydroids and fine algae.  Pulau Hoga, Tukang Besi Archipelago, SE Sulawesi, Indonesia. [Operation Wallacea].

The body is translucent white with orange internal organs showing through. The cerata are arranged in clusters down both sides of the body with the number of cera per cluster decreasing towards the posterior end. The cerata are translucent white with an internal dark red area and are streaked with white.  The rhinophores are long, translucent cream coloured with a more solid cream / orange band towards the tips.  The bucal mass is white and there is a distinctive orange patch on either side of the head. Eye spots are just visible behind the rhinophores.  Photos: Lindsay Warren

What do you think it is?
All the best
Lindsay Warren

Warren, L., 2000 (Mar 23) Cratena lineata from SE Sulawesi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Lindsay,
This is Cratena lineata which has a wide Indo-West Pacific distribution. It is unusual, but not unknown, for there to be no lines on the body.
Best wishes,
Bill Rudman.