Re: Melibe megaceras from Red Sea

March 15, 2005
From: Bill Rudman

Since writing my comment of Oren Lederman's find of Melibe megaceras from the Red Sea [#13309] I have found two earlier records of this species from the Red Sea but identified as Melibe bucephala Bergh 1902.

Schuhmacher (1973) reports on the feeding and swimming behaviour of this animal as Melibe bucephala from Eilat, [Israel, Gulf of Aquaba, Red Sea]  and Yonow (2000) publishes a photo and records specimens also from Eilat. Schumacher observed it feeding by closing its oral hood over algal filaments and wiping them clean.

It is difficult to be sure what Melibe bucephala is. Bergh described it on the basis of a single preserved animal from Thailand, in which most of the cerata had neem lost. No illustration is available of the living animal. In Gosliner's revision (1987) he lists some distinguishing features including rhinophore sheath - flattened and leaflike in M. bucephala and with a long posterior papilla in M. megaceras. The oral hood of M. bucephala has 5 rows of papillae but there are only two in M. megaceras. Also bergh describes jaw plates in M. bucephala while in M. megaceras. they are absent. Both Schuhmacher's and Yonow's photos match M. megaceras. Schuhmacher reports that his animal had 2 rows of papillae on the oral hood, and small mandibles, which are reported to be absent in M. megaceras. However it is not clear if Schuhmacher was actually reporting on specimens he had dissected or was basing his statement on Bergh's description of M. bucephala.

At this stage I would identify your animal as M. megaceras. There is no sure way of confidently re-identifying Bergh's M. bucephala.

  • Bergh, L.S.R. (1902) The Danish Expedition to Siam 1899-1900. 1. Gasteropoda Opisthobranchiata. Det Kongelige Danske Videnskabernes Selskabs Skrifter. 6 Raekke. 12(2): 153-218. (Pls.1-3)
  • Schuhmacher,  H. (1973) Notes on occurrence, feeding, and swimming behaviour of Notarchus indicus and Melibe bucephala at Elat, Red Sea (Mollusca: Opisthobranchia). Israel Journal of Zoology, 22:  13-25.
  • Yonow,  N. (2000) Red Sea Opisthobranchia 4: The orders Cephalaspidea, Anaspidea, Notaspidea and Nudibranchia: Dendronotacea and Aeolidacea. Fauna of Arabia, 18: 87-131.

Bill Rudman

Rudman, W.B., 2005 (Mar 15) Re: Melibe megaceras from Red Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Melibe megaceras

Related messages

  1. Melibe megaceras from the Red Sea
    From: Oren Lederman, March 12, 2005
  2. Melibe megaceras from the Great Barrier Reef
    From: Bill Rudman, May 6, 2003
  3. Melibe megaceras from Malaysia
    From: Harry Erhardt, April 17, 2003
  4. Melibe megaceras - detail of the head
    From: Bill Rudman, April 17, 2003
  5. Melibe megaceras from Malaysia (2)
    From: Harry Erhardt, April 17, 2003
  6. Melibe megaceras - anatomical details
    From: Bill Rudman, April 17, 2003

Show factsheet and all related messages