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It is Goniodoris sp. 2 in IPN:
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs. Sea Challengers Natural History Books.
Gig Harbor, Washington. 426pp. at page 125
It was originally posted at these websites as Goniodoris sp. A Genus: Forbes & Goodsir, 1839.
For some genera, such as Trinchesia is the alphabet almost through. I had to change the distinguishing alphabetic character into a number. I have chosen 2-digit numbers, even though '01' looks a little bit stupid, and now is only the genus italic written.
More information on Goniodoris sp. 01 as Goniodoris sp.1 are on Bill Rudman's Sea-Slug Forum!