Siphopteron sp. 3? from Great Barrier Reef

January 14, 2004
From: Nils Anthes

Note added 15 January 2004: This is considered to be Siphopteron quadrispinosum. See message.

Dear Bill,
This little Siphopteron [Siphopteron sp. 3 on the Forum] with only 1.5-5 mm body length (adults!) is currently quite abundant in algal patches around Lizard Island (QLD, Australia) in shallow water depths. Their colouration is rather constant, there is only little variation in which of the red stripes on the posterior shield, head shield and parapods are present.

Interestingly, Marshall & Willan's Heron Island book has a colour drawing of a Gastropteron with exactly the same colour pattern. I wonder whether this is really some sort of convergent colour pattern, or whether they missed the ridge in the siphon (their drawing clearly shows none, while the animals found here conspicuously have one; see also my separate message to another species of Siphopteron.
Best wishes

Anthes, N., 2004 (Jan 14) Siphopteron sp. 3? from Great Barrier Reef. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Nils,
I am interested in your comment about many animals. If you have photos of other colour variants they would be very welcome. If there are animals with red lines on the parapodia like the ones from Japan that would be quite a good link. For that matter any colour variants would be useful. The other thing it would be nice to know is what they eat! I wouldn't be surprised if they eat small flatworms like your little Chelidonura species so if you have the opportunity a little test could solve a long-standing riddle

I am pretty sure your animal is the recently described Siphopteron leah Klussmann-Kolb & Klussmann, 2003 but I can't find a copy of the description at the moment so am a little hesitant to be definite until I read it again. It was collected in Nth Queensland, and from memory, has a bright yellow body with red lines along the siphonal crest, the parapodia, across the visceral hump and along the flagellum.

Although I am in no position to speak for Marshall & Willan, my first thought would be that their Gastropteron sp. 1 is the same species and the siphonal ridge was missed. It seems the 2.5mm long specimen was collected by a third party during survey work and painted by someone who may not have noticed or realised the significance of a ridge in the tiny siphon. I suspect at that size, the ridge would have been very difficult, if not impossible, for Marshall & Willan to see in the preserved animal.

• Klussmann-Kolb, A. & Klussmann, A. (2003) A new species of Gastropteridae (Gastropoda, Opisthobranchia, Cephalaspidea) from tropical Northeast Australia. Zootaxa, 156: 1-12

Best wishes
Bill Rudman

Rudman, W.B., 2004 (Jan 14). Comment on Siphopteron sp. 3? from Great Barrier Reef by Nils Anthes. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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