Costasiella formicaria from Japan

July 18, 2008
From: Nishina Masayoshi

Dear Bill,

This animal have found on or in some green algae on sandy bottom. The first photo of this animal was posted to some BBS as an unidentified sea slug in May 2004. At the time, I and Dr.Jensen agreed that this animal is most probably Costasiella formicaria (Baba, 1959) which described as Stiliger formicarius (Baba, 1958). Baba revised this animal as C. formicaria later (Baba, 1961).

Location: Futou beach, Izu Peninsula.
Depth: -8 m. water temp: 14 C degree.

  • Baba, K. (1959) The family Stiligeridae from Japan (Opisthobranchia - Sacoglossa). Publications of the Seto Marine Biological Laboratory, 7: 327-334.
  • Baba, K (1961) Three new species of the genus Catriona from Japan (Nudibranchia - Eolidacea). Publications of the Seto Marine Biological Laboratory 9(2): 367-372, Pls.14-15.

Best Regards,
Nishina Masayoshi

nishina@wips.co.jp

Nishina Masayoshi, 2008 (Jul 18) Costasiella formicaria from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21718

Dear Nishina,

Thanks for these photos. It certainly looks like a Costasiella and it also looks identical to Baba's original description of Stiliger formicarius. I had missed Baba's note moving the species from Stiliger to Costasiella as he successfully hid the note as a postscript at the end of a paper on some totally unrelated cuthonid aeolids (Baba, 1961). It is good to be able to draw this to everyone's attention.

I had thought that species of Costasiella fed on species of the algal genus Avrainvillea. Your animals seem to be eating a filamentous algae.  Perhaps Kathe can let us know if species of Costasiella eat algae other than Avrainvillea.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Jul 18). Comment on Costasiella formicaria from Japan by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21718

Factsheet

Costasiella formicaria

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  1. Re: Costasiella formicaria from Japan
    From: Nishina Masayoshi, September 18, 2008
  2. Re: Food of Costasiella formicaria
    From: Nishina Masayoshi, July 24, 2008
  3. Re: Food of Costasiella formicaria
    From: Kathe R. Jensen, July 24, 2008
  4. Re: Food of Costasiella formicaria
    From: Nishina Masayoshi, July 23, 2008
  5. Re: Costasiella formicaria from Japan
    From: Kathe R. Jensen, July 21, 2008

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