Three? species of Halgerda from Kerama Island

March 16, 2000
From: Atsushi Ono

Dear Bill
Thank you for ID of Goniodoris glabra.

I have attached some Halgerda species.
The UPPER one is probably H. dalanghita.
I found them underside of a dead coral
at 10m depth, Kerama Is. near Okinawa.
The bigger animal is 30mm long. This species is very rare, I have seen only these two individuals here.

LOWER LEFT is probably H. diaphana.
This size is about 40mm long. I found this at 20m depth crawling a rock, Kerama Is. near Okinawa. This is common species here in winter to early summer. I have seen over 30 individuals,

LOWER RIGHT is probably a juvenile of H. diaphana. This is about 5mm long, found at 7m depth underside of a dead coral.
A juvenile is very rare... I have seen only this one.

Could you check these photos?

Atsushi Ono

Ono, A., 2000 (Mar 16) Three? species of Halgerda from Kerama Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Atsushi,
I think you are correct with your identifications of H. dalanghita and the larger H. diaphana. I am not however sure of the third juvenile specimen.
Could it possibly be H. guahan?. I don't know if that species has any sign of orange at the mantle edge, and I don't know if the black spots on the gills and rhinophores are proportionally larger in juveniles. Fortunately Clay Carlson & Patty Jo Hoff, who described that species will set me straight if I am wrong.
Best wishes,
Bill Rudman.

[Note added March 19, 2000: See carlson & Hoff message identifying juvenile as H. diaphana.]

Rudman, W.B., 2000 (Mar 16). Comment on Three? species of Halgerda from Kerama Island by Atsushi Ono. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Halgerda dalanghita from Sodwana Bay
    From: Colin Ogden, August 19, 2008
  2. Halgerda dalanghita from the Solomon Islands
    From: Barbara Hanchard, August 13, 2008
  3. Halgerda dalanghita? from Japan
    From: Nishina Masayoshi, March 11, 2002
  4. Halgerda dalanghita from Japan
    From: Rie Nakano, January 10, 2002

Show factsheet and all related messages