NEW DISCOVERIES AT THE PLIOCENE (EARLY BLANCAN) ALWAYS WELCOME INN FOSSIL SITE, BAKER CITY, OREGON

Davis et al. (2005, GSA Abstracts with Programs, v. 37, no. 6, p. 8), described fossil sunfish, minnows, gastropods, bivalves, charophytes, diatoms, sponge spicules, bird bones, and a rodent tooth found at the Always Welcome Inn site between 2002-2005. Continued work at this productive site has added to the fauna. New finds include the minnow, Achrocheilus; fossil turtle shell; bones and/or teeth of frogs, salamanders, rabbits, primitive voles, beaver, muskrat (or ground squirrel?), camel; and a small carnivore; bird bones; and root casts and plant fragments. A fragment of the tibia of a camelid (llama) was found in the gravels overlying the unconformity at the top of the sequence. Fossils of rapidly-growing (warm water) sunfish are found in both the shallow lake deposits in the lower 5.5 m of the sequence and the stream sediments in the upper 3.5 m of the section. Bones of slow-growing (cold water) sunfish have been found in a 1 m-thick transition zone between the lake and stream sediments. The vertebrae of the salamander, Ambystoma, show a continuous passageway for the notochord through the centra of the vertebrae. This suggests that the salamanders were mostly relatively young, but large, larval (neotenic) forms. The beaver tooth is a left upper first molar with an occlusal pattern similar to that of Dipoides vallicula from the late Hemphillian to early Blancan deposits near Little Valley, OR. The occlusal pattern of the lower first molar of the primitive vole found at the Always Welcome Inn is closer to that of Cosomys primus from the Hagerman local fauna than the occlusal patterns of Mimomys panacaensis from Panaca, NV, Mimomys sawrockensis from Alturas, CA, Ogmodontomys poaphagus from Verde, AZ, and Ophiomys mcknighti from White Bluffs, WA. The Always Welcome Inn vole may be an ancestor of Cosomys and, possibly, Ogmodontomys, but additional lower first molars need to be found to confirm this hypothesis (Robert A. Martin, written comm., 2006).