Siphopteron sp. 1.
Known only from Kerama Is., near Okinawa, Japan.
Kerama Island, Japan, about 5m depth. 3 individuals were found in May, 1999, 3mm long. PHOTO: Atsushi Ono.
See Atsushi Ono's message below.Authorship details
Rudman, W.B., 1999 (July 23) Siphopteron sp. 1. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/siphsp1
December 21, 1999
From: Atsushi Ono
I encountered Siphopteron sp. 1 in which the tip's orange color is very light.
5m depth, 3mm long. November 1999 at Kerama Is. I try to find lighter than this.
email@example.comOno, A., 1999 (Dec 21) Colour form of Siphopteron sp. 1. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1696
Thanks very much for the photo. It certainly is much lighter than the earlier photos of Siphopteron sp. 1. Unfortunately I don't think we are going to be able to tell whether this means that Siphopteron sp. 1 and Siphopteron sp. 2 are colour forms of each other until we can compare the internal anatomy of them both. Both seem to have a slender 'tail' off the rear of the visceral hump and another slender projection from the posterior tip of the foot so there are not any other easily visible external characters we can look for.
July 28, 1999
From: Atsushi Ono
They may be same species. But I have never seen a middle type. Their only color marks are those shown in the photo.
Siphopteron sp.2 has no color mark, it is only white.
firstname.lastname@example.orgOno, A., 1999 (Jul 28) Another photo of Siphopteron sp. 1.. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1124
Thanks for the extra photo. In this photo there doesn't seem to be any sign of a rhinophoral crest. Perhaps this species will turn out to be a Gastropteron. Also in this photo the white speckling doesn't seem to be as pronounced.
July 27, 1999
From: Bob Bolland
After viewing Atsushi Ono's recent posting of his Karama gastropterids, I thought I'd send in one from Okinawa. This one appears to be close to his Siphopteron sp. #1, but without the orange pigmentation.
Scans from two separate photos of the same animal, the second is a bit of detail of the siphon; both photos are poor in quality but the approx. 3mm size wasn't conducive to my photography techniques.
Seragaki, Okinawa / 4 May 1997 / from 55m / size: approx. 3mm / water temp. 21.2C
The animal was found as a collaterally-collected specimen ... later at home while inspecting a zip-loc bag of misc. cnidaria, algae, coral rubble and sand, I found the tiny animal. It swam about in the photo tank by actively flapping its parapodia.
All the best,
email@example.comBolland, R.F., 1999 (Jul 27) Siphopteron sp. 1? from Okinawa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1119
I guess the speckled white appearance of Atsushi's Siphopteron sp. 1 is very similar to yours, but my first guess would have been his Siphopteron sp. 2. I guess it depends on whether his Siphopteron sp. 2. is speckled, as in Siphopteron sp. 1, or a much more uniform white?
The close-up of the siphon makes me wonder whether it should be considered a species of Gastropteron as I can't see any indication of the siphonal crest considered characteristic of the genus Siphopteron.
July 26, 1999
From: Atsushi Ono
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.
firstname.lastname@example.orgOno, A., 1999 (Jul 26) Siphopteron sp. from Kerama Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1107
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?
July 26, 1999
From: Erwin Koehler
can you tell me the authority of the genus "Siphopteron" - I've searched the web and used Steve Long's "bibliographic citations search enigine"
at http://www.oz.net/~miranda/searchpara.html - no result.
Medslugs.Koehler@t-online.deKoehler, E., 1999 (Jul 26) Information on Siphopteron. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1117
Terry Gosliner proposed the genus in a review of the family Gastropteridae in 1989, to distinguish a group of species which had previously been placed in the genus Gastropteron. Like Gastropteron they have up to 6 outer lateral teeth, but unlike Gastropteron they have a modified penis with a spermatic bulb. The only external character seems to be the presence of a ridge along the siphon which usually extends as a prominent tapering rod at the tip of the siphon. I can't see this feature clearly in either Siphopteron sp. 1. or Siphopteron sp. 2.
Reference: Gosliner. T.M. (1989) Revision of the Gastropteridae (Opisthobranchia: Cephalaspidea) with descriptions of a new genus and six new species. The Veliger, 32(4): 333-381.
Bill Rudman.Rudman, W.B., 1999 (Jul 26). Comment on Information on Siphopteron by Erwin Koehler. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1117