Roboastra luteolineata vs Tambja verconis

October 25, 2001
From: Ross and Diane Armstrong

Dear Bill,
Thought you might enjoy these photos taken at the Poor Knights on Sunday. Diane made the discovery of Roboastra luteolineata with its mouth full of a Tambja verconis. The visibility was only about 5m so it did not make for the best photographic opportunities. We found it with less than half the T. verconis remaining and watched it slowly eat it down to less than a third remaining before we ran out of film. We went back to our boat and changed film but when we returned 45 minutes later it had finished its meal and looked full to bursting. What we found particularly interesting was how it extended its mouth to feed.
Kind regards
Ross and Diane Armstrong

Armstrong, R. & Armstrong, D., 2001 (Oct 25) Roboastra luteolineata vs Tambja verconis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Ross & Diane,
What a wonderful find - though a bit sad for the Tambja. It is certainly convincing support for my view that the striped animal is a species of the nudibranch-hunting genus Roboastra rather than the bryozoan-feeding genus Tambja. Actually in your upper photo we can see the whole food chain, for at the bottom left I can see some small branches of the bluish arborescent bryozoan Bugula dentata on which Tambja verconis feeds.

Although we call the mollusc radula their 'teeth' they work in quite a different way to vertebrate teeth. A carnivorous vertebrate like a dog or a lion woud use its teeth to bite off or tear off chunks of flesh and swallow them. The mollusc radula can perhaps be compared with having teeth on our tongue. Although they can be manipulated in ingenious ways, molluscs have never evolved a way to use the radula to bite of large chunks. In carnivorous hunters the teeth have become a set of grappling hooks which can grab and hold on to their prey while the the 'oral tube' which is a very extensible region just inside the mouth, extends out of the mouth by turning inside out, and wraps itself around the prey. Once it has done this it can then pull itself and the prey back into its body for digestion.

I think this is the first record of anyhting feeding on Tambja verconis and I don't know of any observations of Roboastra luteolineata feeding in Australia or NZ. Atsushi Ono has a couple of photos of it in his book feeding on another species of Tambja in Japan.

Thanks again for sharing this very interesting observation.
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Oct 25). Comment on Roboastra luteolineata vs Tambja verconis by Ross and Diane Armstrong. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Roboastra luteolineata laying eggs
    From: Deb Aston, May 6, 2010
  2. Re: Roboastra luteolineata - Feeding behaviour!
    From: Graham Abbott, August 4, 2007
  3. Re: Roboastra luteolineata - Feeding behaviour!
    From: Graham Abbott, July 24, 2007
  4. Roboastra luteolineata - Feeding behaviour!
    From: Graham Abbott, January 23, 2007
  5. Roboastra luteolineata eating Nembrotha kubaryana
    From: K. Anderson, February 7, 2006
  6. Roboastra luteolineolata from Great Barrier Reef
    From: Pasquale Pascullo, December 19, 2005
  7. Re: Feeding habits of Roboastra
    From: Bieke Daneels, July 10, 2004
  8. Roboastra luteolineata from Kapalai
    From: Maliza, June 4, 2003
  9. More on Roboastra feeding
    From: Ross & Diane Armstrong, October 26, 2001
  10. Roboastra luteolineata from the Solomons
    From: Scott Johnson, September 30, 2001
  11. Roboastra cf. luteolineata from Sth Africa
    From: Valda Fraser, July 3, 2001
  12. Re: T. affinis v. R. luteolineata
    From: Ross and Diane Armstrong, April 24, 1999
  13. Tambja affinis v. Roboastra luteolineata
    From: Ross Armstrong, April 23, 1999
  14. Re: Roboastra luteolineata
    From: Ross Armstrong, February 24, 1999
  15. Robastra luteolineata - new for New Zealand
    From: Ross Armstrong, February 22, 1999

Show factsheet and all related messages