Webmaster Mike just ran across this 75 mm monster in Bali last week. What a beauty. The large red patches on the dorsum of this species give rise to the name "cruenta" which means "blood spattered." Platydoris cruenta is a large dorid nudibranch with a very flat, oval body. The edge of the mantle is often ruffled and the gill is large and spreads flat upon the dorsum. This species is very similar to Platydoris formosa , who also has large red patches, but P. cruenta has brown lines instead of brown specks. The underside of the mantle is white with brown lines near the foot, and scattered red patches. The sole of the foot can also have brown lines.
The species is most often seen at night when it emerges to forage on sponges. You will also know of its presence by it's spectacular colored egg mass . The large coiled egg ribbon is bright blood red. The aposomatic color of the egg mass likely warns predators that the eggs are toxic. Another red colored dorid species with red, toxic eggs is Hexabranchus sanguineus.
Specimens of this species have been documented from the western Pacific Ocean localities of the Great Barrier Reef, New Caledonia, the Philippines and Indonesia.
Several of my colleagues have just published a paper reviewing the genus Platydoris, adding several new species. The paper is listed below.
Good show Mike. We look forward to seeing more of your catches from this trip.
K.M. Dorgan, Á. Valdés & T.M. Gosliner. 2002. Phylogenetic systematics of the genus Platydoris (Mollusca, Nudibranchia, Doridoidea) with depictions of six new species. Zoologica Scripta. 31(3): 271-
David W. Behrens
Pacific Coast Nudibranchs
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