Pseudoceros ferrugineus  Hyman, 1959

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Let me quote the description of Pseudoceros ferrugineus by Marcela Bolanos at LifeDesks:
"Large body with several marginal deep ruffles. The color is dark red with the dorsal surface covered by compacted small white dots given the appearance of a brilliant pink surface. There are two marginal bands, red and orange without white dots. Ventrally, the color is red being more intense towards the margin. Pseudotentacles formed by simple broad folds of the anterior margin with numerous marginal eyes."
This picture was posted on 31 May 2012 at these websites as Pseudocerotidae sp. 02  Family: Lang, 1884
I found by chance on 25 August 2012 a picture of the same colour variant at Philibert Bidgrain's South-west Indian Ocean Flatworm site.
Let me quote Philibert Bidgrain:
"The general color is a bright rusty red blending into a narrow margin of brillant orange. The dorsal surface is flecked with white. The white flecks diminish towards the margin where the rusty red background is much more in evidence forming an inner margin red without dots. The bright orange marginal line is free from spots." and: "Colour pattern variable, especially the width of the marginal bands and intensity of the background color."
I still find it hard to believe that the above 3 specimens are of the same species!
More pictures are at Dr.Wolfgang Seifarth's website Marine Flatworms of the World!, from Izu, Japan, from Okinawa, Japan, from Panglao, Philippines, and 2 more from the Philippines, and from many locations at Nudi Pixel.