Siphopteron sp. from Kerama Island

July 26, 1999
From: Atsushi Ono

Dear Bill,
Could you help me with these other opisthobranchs from Kerama Is, near Okinawa. They are three gastropterids, two species of Siphopteron and one Gastropteron.

They are all very small animals.

I think this first one is a species of Siphopteron. It is about 3mm long. It was found with the other species of Siphopteron sp. 2 in mixed sand and coral rubble, about 5m depth. 3 individuals were found in May, 1999.

Atsushi Ono

Ono, A., 1999 (Jul 26) Siphopteron sp. from Kerama Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Atsushi,
I have separated your message into three. The other two species are Siphopteron sp. 2 and Gastropteron sp. 1. I don't recognise any of them. Could you give us a short description of the colour to accompamy the photos. For example this species seems to be translucent with white speckling. The tip of the siphon is deep orange and there appears to be a dark orange smudge on the front edge of the head and another on the siphon. Are there any other colour marks I can't see in the photo? And did the the three animals have the same marks? The reason I ask is that your Siphopteron sp. 2 differs only in not having any colour marks. I wondered if it were possible they were forms of the one species?

The only external character of the genus Siphopteron is that the siphon has a prominent dorsal ridge or crest. I can't see this in your photo. Can you confirm there is one?

Best wishes,
Bill Rudman.

Rudman, W.B., 1999 (Jul 26). Comment on Siphopteron sp. from Kerama Island by Atsushi Ono. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Siphopteron sp. 1.

Related messages

  1. Colour form of Siphopteron sp. 1
    From: Atsushi Ono, December 21, 1999
  2. Another photo of Siphopteron sp. 1.
    From: Atsushi Ono, July 28, 1999
  3. Siphopteron sp. 1? from Okinawa
    From: Bob Bolland, July 27, 1999
  4. Information on Siphopteron
    From: Erwin Koehler, July 26, 1999

Show factsheet and all related messages