Hypselodoris bertschi from Hawaii

Dear Scott,
Thanks for the photos. I think I will go out on a limb here and say that I don't agree that this is H. peasei. Unfortunately the names of these white lined chromodorids from Hawaii have been confused for many years. Kathe Jensen's suggestion that H. bertschi should be synonymised is based on the longstanding misidentification of Pease's Doris prismatica lineata by many authors. Here are some of the main points.

•In 1852, Eydoux & Souleyet named a species Doris lineata from Hawaii. It is really a species of Hypselodoris but as both Doris lineata and Hypselodoris lineata had been used before 1852, Eydoux & Souleyet's name is not available. It is probably the Hawaiian form of Hypselodoris maridadilus.
•In 1860, Pease described a species Doris prismatica, var. lineata. See separate message for full description. He later (1868) corrected the name to Doriprismatica lineata.
•In 1880, Bergh published paintings of Pease's species and gave it a new name Chromodoris peasei on the grounds that Doris lineata Pease was preoccupied by Doris lineata Eydoux & Souleyet.
•Ostergaard, 1955., Kay & Young, 1969., Bertsch & Johnson, 1981., all identified the animal in your photos as Pease's D. lineata.
•Gosliner & Johnson, 1999 name this species H. bertschi identifying it with Pease's, Ostergaard's and Kay & Young's D. lineata.

If you look at Pease's original description and the painting published by Bergh, there are significant external differences. In particular, Pease's species has two orange bands on the rhinophores and both the foot and mantle are bordered with violet. The gill rachis is orange. In H. bertschi there is only one orange band on the rhinophores, and the mantle has an orange border not violet. The gills have an orange tip and orange patch at the base. Pease's description matches almost exactly the species which was described as Hypselodoris andersoni. The colour of the rhinophores, gills, mantle and foot margins, mantle with white lines sometimes joining, all fit as does the size. In my opinion it is H. andersoni which should be synonymised with H. peasei not H. bertschi.

Bill Rudman.