Risbecia pulchella
(Ruppell & Leuckart, 1828)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Family: Chromodorididae

DISTRIBUTION

Indian Ocean. Relatively common in the Red Sea and East Africa. Reported below from southern Thailand.

PHOTO

ALL PHOTOS: Mbudya Is, Dar es Salaam, Tanzania, February 1979. Note characteristic 'tailing' behaviour. 70, 65mm long. PHOTOS: Bill Rudman.

Originally described from the Red Sea, where it coexists with the similarly coloured Risbecia ghardaqana and Chromodoris annulata. See my message comparng these species. In the western Pacific there is another species, Risbecia imperialis, which differs externally only in the absence of the purple border to the foot and the smudged purple reticulate pattern found on the dorsum of this species.

Gohar & Aboul-Ela (1957) studied this species in some detail, and the following paragraph summarises their description of the species. It grows to 10cm fully extended. The mantle is of a somewhat opaque creamy white, marked by a bluish purple tinge in irregular areas on the mantle and sides of the foot. All the dorsal surface of the mantle and the foot is covered with yellowish orange spots of irregular shape and different sizes. The mantle margin is fringed with a thin border of bright bluish violet. The posterior tip of the foot may have a similar border. The front of the mantle forms a veil which continuously waves up and down when crawling. The rhinophores have a white stem and blue leaves. The gills are simple and the colour of the edge can vary from violet to orange yellow in a single specimen. The gills are often branched and wave rhythmically from side to side. When recently spawned, the egg ribbon is reddish orange and it is attached along one edge in a spiral, the free edge being slightly wavy.

These photos show the characteristic 'trailing' behaviour found in all species of Risbecia, where pairs of animals are often found following each other in single file, the second animal in the line usually touching the 'tail' of the one in front. See Erwin Koehler's messages about this behaviour in Risbecia pulchella and Risbecia tryoni.

References:
• Gohar, H. A. F., & I. A. Aboul-Ela. 1957a. The development of three chromodorids (with the description of a new species). Publications of the Marine Biological Station, Al-Ghardaqa, Egypt, 9: 203-228, pls. 1-5.
• Rudman, W.B. (1984) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: a review of the genera. Zoological Journal of the Linnean Society, 81: 115-273.
• Rudman, W.B. (1987) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris epicuria, C. aureopurpurea, C. annulata, C. coi and Risbecia tryoni colour groups. Zoological Journal of the Linnean Society, 90: 305-407.

Authorship details
Rudman, W.B., 2003 (April 8) Risbecia pulchella (Ruppell & Leuckart, 1828). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/risbpulc

Related messages

  1. Re: Risbecia pulchella at rest
    From: Ron Velarde, February 24, 2009
  2. Risbecia pulchella at rest
    From: Valda Fraser, February 16, 2009
  3. Risbecia pulchella - Stretching ?
    From: Kamal El Tawil, June 6, 2008
  4. Trailing Risbecia pulchella from the Red sea
    From: Kamal El Tawil, April 9, 2008
  5. More Risbecia ghardaqana from Thailand?
    From: K. Kalani Patterson, February 5, 2008
  6. Re: Risbecia ghardaqana from Hurghada, Egypt
    From: Yahia Mokhtar, October 30, 2007
  7. Risbecia pulchella from the Red Sea
    From: Larry Dupriest, October 30, 2007
  8. Risbecia ghardaqana ? from Muscat, Oman
    From: Yahia Mokhtar, September 21, 2007
  9. Mating Risbecia pulchella from Tofo, Mozambique
    From: Natasja Vandeperre, August 24, 2007
  10. Risbecia ghardaqana? from Indonesia
    From: Grace Wong, August 18, 2007
  11. Re: Rispecia ghardaqana? from South Africa
    From: Colin Ogden, May 9, 2007
  12. Risbecia ghardaqana? from the Red Sea
    From: Kamal El Tawil, July 24, 2006
  13. Risbecia pulchella from the Red Sea
    From: Kamal El Tawil, March 6, 2006
  14. Periclimenes imperator on mating Risbecia pulchella
    From: Matan Ninio, August 3, 2005
  15. Risbecia pulchella from Reunion Island
    From: Stefaan Dewulf, February 1, 2005
  16. Risbecia pulchella from Thailand
    From: Spencer Huang, December 8, 2003
  17. Risbecia pulchella from Red Sea
    From: Leo de Pee, May 22, 2003
  18. Risbecia pulchella from the Red Sea
    From: Oren Lederman, May 17, 2003
  19. Chromodoris hintuanensis or R. pulchella?
    From: Asther M. Lau, May 10, 2003
  20. Risbecia ghardaqana from Andaman Sea
    From: Mary Jane Adams, April 8, 2003
  21. Risbecia pulchella from the Red Sea
    From: Ilan Ben-Tov , April 8, 2003
  22. Risbecia pulchella from the Andaman Sea
    From: Mary Jane Adams, April 8, 2003
  23. Re: Risbecia ghardaqana trailing
    From: Erwin Koehler, April 8, 2003
  24. Risbecia ghardaqana trailing
    From: Sarah Heaney, March 29, 2003
  25. Risbecia ghardaqana - 'trailing' behaviour
    From: Larry Dupriest, March 2, 2003
  26. Risbecia ghardaqana from sthn Thailand
    From: Priscilla Yeo, January 25, 2003
  27. Re: Risbecia pulchella vs. ghardaqana
    From: Ron Velarde, April 6, 2002
  28. Risbecia pulchella or ghardaqana (2)
    From: Erwin Koehler, April 5, 2002
  29. Risbecia pulchella vs. ghardaqana
    From: Erwin Koehler, April 5, 2002
  30. Risbecia pulchella from Bali
    From: Stuart Hutchison, April 4, 2002
  31. Risbecia ghardaqana from the Red Sea
    From: Jim Anderson, January 31, 2002
  32. Is this Risbecia ghardaqana?
    From: Doug Segar, March 14, 2001
  33. Risbecia pulchella - range extension
    From: Michael D. Miller, March 14, 2001
  34. Risbecia pulchella without gills
    From: Valda Fraser, January 12, 2001
  35. Risbecia pulchella from Oman
    From: Gordon T. Smith, October 30, 2000
  36. Risbecia from the Seychelles
    From: Dick Ballendux, November 12, 1999
  37. Risbecia pulchella from Thailand
    From: Bill Rudman, April 12, 1999
  38. 'Trailing' in Risbecia pulchella
    From: Bill Rudman, April 11, 1999
  39. 'Trailing' in Risbecia ghardaqana
    From: Erwin Koehler, April 9, 1999

Show factsheet and all related messages