Pseudoceros jebborum Newman & Cannon 1994
"Jebb's Flatworm"
top photo: Honokohau, Hawai`i (at night)
bottom photo: Lembeh Strait, Indonesia, Bernard Dupont (Wikimedia)

The original 1994 color description reads: "Background cream-orange, grey black laterally near margin and across pseudotentacles. Marginal band wide, cream with a narrow distinct bright yellow rim."

Unfortunately, the "cream-orange" or caramel-colored central band (shown in the photo below) is sometimes almost white (according to photos on the 2004 Newman & Cannon CD). A worm with a white central band would be hard to distinguish visually from the similar "Gold Rim Flatworm" Pseudoceros paralaticlavus. To complicate matters, it seems that the latter species sometimes also exhibits a caramel-colored central band. Cory Pittman raises the possibility that this coloration may be due to a covering of pigmented mucus sometimes, but not always, secreted by each of these two closely related worms.

Cory goes on to suggest, tentatively, that a better character for separating the two species might be the relative widths of the central bands, measured when the worms are crawling. In jebborum the central band is wide, about 1/2 to 3/4 of the animal's total width, whereas in paralaticlavus the central band is narrower, about 1/4 to 1/3 the animal's width. **see below

Another character might be size: according to Newman & Cannon, jebborum grows longer than paralaticlavus: 2.75 in. (70 mm) vs. 2 in. (50 mm) respectively.

P. jebborum is found from the Western Indian Ocean to the Hawaii. However, it seems to be quite rare in Hawaii.

The issue of whether P. paralaticlavus is just another color form of P. jebborum was examined in a 1996 paper by Coggin and Newman, which showed a 6% difference between the DNA of allopatric specimens. An entire web page is devoted to the difficulties of separating the two species visually.


BACK to solid color w marginal bands

BACK to longitudinal stripes

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Another photo of a "white" jebborum
on Mike Miller's Philippine Sea Slugs website

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