Meeting Abstract

P1.127  Wednesday, Jan. 4  Tic tacs from the Eocene of the Pacific Northwest: Significant clypeasteroids from unexpected places MOOI, R.**; BURNS, C.; California Academy of Sciences, San Francisco; California Academy of Sciences, San Francisco rmooi@calacademy.org

Recent discovery of specimens of the sand dollar relative, Fibulariella, from the Yellowstone Hot Spot-derived middle Eocene Crescent Formation (50ma) at Tongue Point, Clallam County WA, represents the first northeastern Pacific occurrence of this genus. These extremely miniaturized laganine clypeasteroids (<5 mm test length) are found serendipitously preserved in sediments lodged in crevices between basalt pillows and breccia associated with possible black sand beach deposits. Associated fauna include warm water corals, bryozoans, mollusks, brachiopods and at least 3 other species of echinoids. The geographically closest Eocene relative of this likely new Fibulariella species is a Gulf of Mexico form presently and incorrectly known as a Fibularia, F. texana. Fibulariella is only now emerging as a taxon significantly different from Fibularia in many respects. The two genera are superficially similar due to their small size and apparent paedomorphosis, but differ greatly in overall plate architecture, basicoronal arrangement, petaloid shape, and details involving the apical system. The discovery of this new Fibulariella from the northeastern Pacific sheds new light on the origins, affinities, and distribution of these very early clypeasteroids.