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This species is as Piseinotecus sp. 1 in IPN at page 353:
The specimen in IPN has whitish rhinophores and oral tentacles, the cerata are basally translucent white, merging gradually into orange. IPN writes: "Yellow pigment forming a continous line along the undulating notal margin. Black viscera visible through the notum."
This specimen looks identical to the specimen in IPN.
I can see no yellow line at the specimen in IPN, nor at the specimen from Luzon.
A picture by Kevin Lee of a specimen from Malaysia is the Opisthobranch of the Week 17 August 2009 at Michael D. Miller's Slug Site, this specimen looks almost identical to the specimen in IPN, it lacks also the yellow line.
Gosliner, Terrence M., David W. Behrens & Ángel Valdés. 2008. Indo-Pacific Nudibranchs and Sea Slugs.
Sea Challengers Natural History Books. Gig Harbor, Washington. 426 pp.
How to cite:
Köhler, E. (2017), published 14 January 2017, Piseinotecus sp. 01 Genus: Er. Marcus, 1955
available from https://www.Philippine-Sea-Slugs.com/Nudibranchia/Dexiarchia/Piseinotecus_sp_01.htm