Phyllidia coelestis (?) with black line on sole

December 28, 2000
From: Yasman

Dear Sir,

I quite wonder to identify this species. This species I found in Karang Lebar Atoll, Thousand Islands, Indonesia. In general, it looks like Phyllidia coelestis even though the 'Y' shape does not exist. But it has 3 black bands and also has tubercle form and pattern like Phyllidia coelestis. In addition, I found the juvenile of Phyllidia varicosa which look like very similar to the adult pattern. So, I think it should not be juvenile of Phyllidia varicosa. It is amazing, however, because it also has black line at the foot sole. This character belongs to the species Phyllidia varicosa, not Phyllidia coelestis. What do you think?


Yasman, 2000 (Dec 28) Phyllidia coelestis (?) with black line on sole. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Yasman,
As you say, the photo of the dorsal surface certainly looks like Phyllidia coelestis. I don't know another species with a dorsal median black band. However your mention of a median black line on the sole is very puzzling. As far as I know only four species have a median longitudinal black line on the sole:
Phyllidia varicosa, Phyllidia tula, Phyllidia elegans, Phyllidia carlsonhoffi.

None of these has a dorsal coloration like your animal. At this stage I would tentatively identify as P. coelestis. I think we still have some work to do on the presence and absence of the black line on the sole of the foot of these species. Unfortunately this character is usually not recorded (and seldom photographed), so it is difficult to accumulate information. I found some puzzling black lines in specimens in Lifou, which when I get a chance I must try and make sense of.
Best wishes,
Bill Rudman.

Rudman, W.B., 2000 (Dec 28). Comment on Phyllidia coelestis (?) with black line on sole by Yasman. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Fryeria or Phyllidia from Hachijo Ids Japan
    From: Shouichi Kato, March 28, 2002
  2. Phyllidia coelestis? from Sulawesi
    From: Lindsay Warren, April 8, 2001
  3. Fryeria (?) with black line on sole
    From: Yasman, December 30, 2000

Show factsheet and all related messages