Philinopsis mating from Korea

June 17, 2002
From: Dong Bum, Koh

Dear Bill,
I suspected that this was Aglaja depicta (Renier, 1807) but when I look closely I realised that it was not one but two animals. I presume they are mating. Can you tell me if this is really two, and if this is the mating position.

Date: 2001.March.
Location: Seogwipo, Cheju Island, Korea.
Depth: 20m.
Photo by: Dong Bum, Koh

With best Regards.
Dong Bum, Koh

drkoh@seasee.co.kr

Koh, D.M., 2002 (Jun 17) Philinopsis mating from Korea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7231

Dear Dr Koh,
Thanks for this interesting photo. Yes these are two aglajids mating. The penial sac is on the anterior right corner of the head, the penis only extending out of the sac during mating. The common male & female genital opening is at the back of the body on the right side, on the floor of the reduced mantle cavity. Sperm reaches the penis in a ciliated groove running along the right side of the body from the common genital opening. As in the Sea Hares, aglajids mate 'head to tail' the anterior one acting as female and the posterior one as male. As with Sea Hares, a number of animals can mate simultaneously by forming a mating chain, in which the animals in the middle of the chain act as both male and female. Although I have no photos, I have observed 10 or more animals of the little black aglajid from New Zealand, Melanochlamys cylndrica in such a chain.

Now to the identity of your animal. The colour of the two animals in your photo show just how variable some of these species can be. It does look quite like A. depicta but it is unlikely that that mediterranean species would be found in the tropical NW Pacific. I am pretty sure your animal is a colour form of the widespread Indo-West Pacific species Philinopsis cyanea. It ranges in colour from animals with a dark blue black background colour to those like yours woth a translucent body with a brownish reticulate pattern. What all these colour forms have in common is traces of two or three large whitish patches down the midline of the headshield and two pairs of orange-yellow longitudinal lines on each side of the headshield. Another species, P.gigliolii (Tapparone-Canefri, 1874) was described from Japan from preserved specimens. The colour was reported to be a buff-white reticulated with brown or ash-coloured lines, and the head shield was said to have a median longitudinal pale line. In Okutani, 2000 [Marine Mollusks in Japan: Pl.374 fig.2] there is a photo which fits that description. It appears to be distinct from P. cyanea.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jun 17). Comment on Philinopsis mating from Korea by Dong Bum, Koh. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7231

Factsheet

Philinopsis cyanea

Related messages

  1. What is Philinopsis cyanea doing?
    From: Valda Fraser, August 6, 2008
  2. Dark colour form of Philinopsis cyanea
    From: Hugues Flodrops, August 5, 2008
  3. Philinopsis cyanea from Reunion Island
    From: Hugues Flodrops, February 18, 2008
  4. Philinopsis taronga? from Reunion Island
    From: Hugues Flodrops, February 18, 2008
  5. Philinopsis cyanea from Perth
    From: Brent Murdoch, January 17, 2007
  6. Philinopsis cyanea? from Taiwan
    From: Ching-Yao Chan, May 17, 2006
  7. Philinopsis cyanea? from Victoria, Australia
    From: Trevor McMurrich, March 24, 2006
  8. Re: Aggregation of Stylocheilus striatus in Indonesia [1]
    From: Paul Whitehead, January 23, 2006
  9. Philinopsis gardineri? from Reunion Island
    From: Philibert Bidgrain, December 13, 2005
  10. Re: Philinopsis cyanea mating in Reunion Island
    From: Francis & Pirjo Pellet, November 25, 2005
  11. Philinopsis cyanea spawning at Reunion Island
    From: Philibert Bidgrain, November 25, 2005
  12. Two big Philinopsis cyanea mating in Reunion Island
    From: Philibert Bidgrain, November 23, 2005
  13. More colour forms of Philinopsis cyanea
    From: Dong Bum Koh, June 13, 2005
  14. Philinopsis cyanea ... eating?
    From: Binyamin Koretz, April 28, 2005
  15. Philinopsis cyanea from South Korea
    From: Dong Bum Koh, April 14, 2005
  16. Philinopsis depicta? from the Red Sea
    From: Binyamin Koretz, April 14, 2005
  17. Philinopsis cyanea? from Indonesia
    From: Francis & Pirjo Pellet, January 13, 2004
  18. Philinopsis cyanea from Port Stephens
    From: Leanne&David Atkinson, May 13, 2003
  19. Philinopsis cyanea & possible egg mass
    From: Leanne Atkinson, May 9, 2003
  20. Philinopsis cyanea from Lembeh Strait
    From: Mary Jane Adams , February 6, 2003
  21. Philinopsis cyanea from Lizard Is
    From: Nils Anthes, February 3, 2003
  22. Philinopsis cyanea from Lord Howe Island
    From: W.B. Rudman, January 10, 2003
  23. Philinopsis cyanea from Lord Howe Is.
    From: Ian Hutton, December 6, 2002
  24. Philinopsis cyanea from Sulawesi
    From: Mary Jane Adams, May 4, 2002
  25. Philinopsis cyanea mating
    From: Julie Marshall, May 4, 2001
  26. Philinopsis cyanea from New South Wales
    From: Erik Schloegl, April 3, 2001
  27. Philinopsis from Mauritius
    From: Owen Griffiths, July 27, 1998

Show factsheet and all related messages