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Let me quote Cory Pittman and Pauline Fiene, they write at their website Sea Slugs of Hawaii:
"This species is similar to the Atlantic Berthella africana (Pruvot-Fol, 1953) and is currently listed on the Sea Slug Forum under the name Pleurobranchus caledonicus Risbec, 1928. It seems likely that further work will confirm it as the latter species but place it in the genus Berthella as suggested on the forum."
Pleurobranchus caledonicus was described from New Caledonia, now there are records from Okinawa, Japan, from the Marshall Islands, from Hawaii, from Queensland, Australia, from Guam (the website NUDIPIXEL is down, the picture from Guam is gone), and from Reunion Island.
I noticed that WoRMS lists it as Berthella caledonica (Risbec, 1928) with the reference Carlson & Hoff (2003), and changed on 29 November 2020
into Berthella caledonica (Risbec, 1928) [Pleurobranchus].
MolluscaBase eds. (2020). MolluscaBase. Berthella caledonica (Risbec, 1928).
Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=872697 on 2020-11-28
Carlson C. & Hoff P.J. (2003). The opisthobranchs of the Mariana Islands.
Micronesica. 35-36:271-293., available online at https://micronesica.org/volumes/35-36, scroll down to 14.
More information on Berthella caledonica as Pleurobranchus caledonicus are on Bill Rudman's Sea-Slug Forum!
How to cite:
Köhler, E. (2020), published 29 November 2020, Berthella caledonica (Risbec, 1928)
available from https://www.Philippine-Sea-Slugs.com/Pleurobranchida/Berthella_caledonica.htm