Odontoglaja guamensis
Rudman, 1978

Order: CEPHALASPIDEA
Family: Aglajidae

DISTRIBUTION

Originally described from Guam but now known from many sites in the tropical western Pacific Ocean.

PHOTO

Two colour forms from Koumac, northern New Caledonia, October 1993. Maximum length about 11mm. PHOTOS: Bill Rudman.

Until this interesting animal was discovered by Clay Carlson & Patty-Jo Hoff in Guam, all aglajids were characterised by the lack of radular teeth and gizzard plates. These predatory opisthobranchs, related to Philine, have reached a peak in predatory specialisation eating highly mobile prey animals including polychaete worms and other opisthobranch molluscs.

Odontoglaja guamensis has philinid-like radular teeth and a rudimentary gizzard, but in other anatomical features is clearly an aglajid. Although modern taxomonists shouldn't talk about "missing links" this species has an interesting mixture of ancestral and "modern" (derived) characters.

• Rudman, W.B.,1978. A new species and genus of the Aglajidae and the evolution of the philinacean opisthobranch molluscs. Zoological Journal of the Linnean Society, 62: 89-107.

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