Janolus capensis from False Bay, Sth Africa

June 23, 2005
From: Wilhelm van Zyl

Hi Bill
Concerning your comments about the other animal [#14092 ]:
 It was actually this ridge or absence thereof  that made me think it was Bonisa. I cannot see any ridge between the rhinophores in that picture. On my next dive I will specifically look for this. Another thing that made me wonder was the shape of the cerata, they are more club shaped than the other Janolus specimens I have.

I do not know if this can be used to differentiate between the 2. I am sending you my best photo of Janolus capensis to date. I took it on a dive site called Castle Rock near Simons Town in False Bay at about 5m water depth. Although you cannot see the ridge I am sure this is Janolus.

Regards
Wilhelm

diving@cyberdale.co.za

van Zyl, W., 2005 (Jun 23) Janolus capensis from False Bay, Sth Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14114

Dear Wilhelm,
The large caruncle between the rhinophores is probably the best bet but as you can't see that in many photos it doesn't help much. I don't think how flattened the cerata are is a good thing to use as their shape is fairly plastic. One very important feature though is whether there is a branch of the digestive gland in the cerata. There is  branch in species of Janolus, but not in species of Bonisa. In your photo here the reedish-brown branch, which forks near the tip is quite visible.
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Jun 23). Comment on Janolus capensis from False Bay, Sth Africa by Wilhelm van Zyl. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14114

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Janolus capensis

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