Costasiella sp. 3

Family: Costasiellidae


Upper: Lembeh, Sulawesi, Indonesia. On green algae at 10 meters. Less than 5mm in length. December 2002. Photo: Takako Uno
Lower: Negros Oriental Island, Lipayo (near Dumaguete), Philippines, depth 8-11m, March 2003. Photo: Erwin Koehler.

It is not possible to be confidently identify animals from photos alone. However from the range of photos now available it seems that this species of Costasiella shows some variation in the colour of the cerata. The head has a broad brownish band from the rhinophores to the mouth, and their is a second brown patch from the rhinophores back towards the pericardium. The lower half of the rhinophores are white and the upper half is black, although it seems there can be a white or translucent tip in some specimens. The cerata are transparent, with the green speckled contents showing through the body wall. There is an opaque white cap to the digestive gland just below the translucent tip. In some animals there can be a red or pickish spots on the dorsal side of the cerata just below the tip. In one photo, opalescent blue patches can also be seen on the ceratal wall.

I have included here photos which were previously labelled Costasiella cf. kuroshimae. As discussed earlier another species has been identified as C. kuroshimae. It is unfortunate that most species of Costasiella have been described from one or very few specimens. Without a knowledge of their colour variation it is difficult to identify specimens which don't exactly match the original description.

Authorship details
Rudman, W.B., 2003 (April 2) Costasiella sp. 3 [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Costasiella sp. 3 from Bali
    From: Douglas Hansen, August 16, 2009
  2. Re: Costasiella sp. from Ratnagiri, India
    From: Vishal Bhave, May 19, 2009
  3. Costasiella sp. from Ratnagiri, India
    From: Vishal Bhave, May 18, 2009
  4. Costasiella sp. 3 from Bali
    From: Supapong Areeprasertkul, October 28, 2008
  5. Costasiella sp. from Indonesia
    From: Ann Clear, October 28, 2008
  6. Costasiella sp. 3 from the Philippines
    From: Jeffrey de Guzman, October 10, 2007
  7. Costasiella sp. 3 from New Caledonia
    From: Jean-François Hervé, September 21, 2007
  8. Costasiella sp. 3? from Bali
    From: Linda Ianniello, November 30, 2006
  9. Costasiella sp. 3 from Bali
    From: Ian Dunsmore, March 4, 2005
  10. Costasiella sp 3 from Lizard Id, Queensland
    From: Nils Anthes, January 9, 2004
  11. More Costasiella cf. kuroshimae from Philippines
    From: Erwin Koehler, April 2, 2003
  12. Re: Costasiella from Indonesia
    From: Erwin Koehler, March 27, 2003
  13. Re: Costasiella from Indonesia
    From: Kathe R. Jensen, March 17, 2003
  14. Costasiella from Indonesia
    From: Takako Uno, March 15, 2003
  15. Costasiella from the Philippines
    From: Erwin Koehler, May 15, 2002
  16. Costasiella from the Philippines
    From: Erwin Koehler, May 9, 2002

Show factsheet and all related messages