Another record of Polycera hummi from Florida

February 5, 2004
From: Linda Ianniello

Following your recent comments I went out looking for another Okenia evelinae to try and get a better shot. By chance, I found this slug, which is about the same size - maybe 8mm and too small to see distinguishing features very well underwater - on the same bryozoan with an Okenia evelinae. When I got the film processed, I realized I had two different slugs. Once again, the animal is so small the shots are not very good, but this head shot is reasonably focused. The second shot shows the growth it was found on, and a bit better shot of the rhinophores. I think it might be Polycera hummi? Though it is a lot smaller than the other one on the Forum ...

Location: Lake Worth Lagoon, Southeast coast of Florida, USA. Depth: 15 feet. February 1, 2004

Thanks for your help with another identification!
Linda I.

Ianniello, L., 2004 (Feb 5) Another record of Polycera hummi from Florida. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

NOTE added 13 Feb 2004: This is Polycera aurisula. See #12196.

Dear Linda,
Your messages always come up with little surprises. I agree that this is almost certainly a juvenile of P. hummi. I suspect the distance between the blue and yellow banding, and the absence of the inner blue band is because the animal is so small, but I guess it will be worth checking on if you come across the species again.

Then most interesting thing in your message is the bryozoan. I am not an expert on bryozoans but I am pretty sure this is Amathia distans Busk, 1886, which has a circumtropical distribution and is a common in the western Atlantic. It is found from North Carolina to Brazil. The way the zooids are arrange in slightly curved double rows is typical of the species. There is an illustration on the Smithsonian Marine Station at Fort Pierce website at

You may remember in my discussion of Okenia evelinae that I noted that Marcus reported it feeding on Amathia convoluta. My understanding is that true A. convoluta is a South Pacific species so it is quite possible that Marcus's record is a misidentification for Amathia distans. Your bryozoan is quite different from Zoobotryon which has almost transparent stalks and irregularly arranged zooids. The exciting thing is that you found a specimen of the animal I have identified as Okenia evelinae on this bryozoan, which certainly adds weight to my suggestion that it is distinct from Okenia zoobotryon which has only been reported from the bryozoan Zoobotryon.

Best wishes
Bill Rudman

Rudman, W.B., 2004 (Feb 5). Comment on Another record of Polycera hummi from Florida by Linda Ianniello. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Polycera aurisula

Related messages

  1. Polycera aurisula from Florida
    From: Bill Rudman, February 13, 2004

Show factsheet and all related messages