A NEW CRAB FROM THE LATE EOCENE HOKO RIVER FORMATION, OLYMPIC PENINSULA, WASHINGTON: THE WORLD’S EARLIEST RECORD OF EUPHYLAX (DECAPODA: PORTUNIDAE)

Euphylax feldmanni, new species, from the late Eocene Hoko River Formation, northwestern Olympic Peninsula, Washington, represents the first occurrence of Euphylax in pre-Oligocene strata, the earliest fossil record for the subfamily Podophthalminae, and the first record of the genus from the eastern North Pacific. The Hoko River Formation extends from Port Angeles westward to the vicinity of Cape Flattery, Washington. Wave-cut bench and sea-cliffs along the coast from Cape Flattery eastward to Neah Bay, Washington contain, uniquely, a wealth of fossil decapod crustaceans that includes 13 families, 22 genera, and 25 species described thus far. Fossil decapod crustaceans of the westernmost exposures of the Hoko River Formation are allochthonous, preserved in reworked concretions within conglomerates that were deposited as part of a submarine fan system during late Eocene time. The abundance and diversity of this decapod crustacean assemblage suggests down-slope mixing of decapod crustacean fossils derived from strata originally deposited at different depths, representing different paleoenvironments, and differing in geochronologic age. This is exemplified by the occurrence of more than one species of fossil decapod crustacean represented from the same locality, a rare occurrence, further suggesting reworking of concretions from different source areas. The discovery and addition of a fossil species of Euphylax from the Pacific Northwest, U.S.A. greatly expands the paleobiogeography of the genus and adds to the fossil decapod crustacean diversity of the Hoko River Formation.