Paper No. 18
Presentation Time: 9:00 AM-6:30 PM


JACISIN III, John J., Geological Sciences, University of Oregon, 2973 Portland Street, Eugene, MI 97405 and HOPKINS, Samantha S.B., Clark Honors College and Geological Sciences, Univ of Oregon, 1272 University of Oregon, Eugene, OR 97403,

The fossil record of North American salamanders is sparse, so their evolution, phylogenetic relationships, and times of origin are unclear. They are often only represented by isolated vertebrae or other fragmentary fossils, and are only rarely found as carbonized imprints or articulated skeletons. Several partial to nearly complete skeletons, and multiple carbonized imprints from Oligocene localities in the John Day and Fisher Formations of Oregon represent post-metamorphic individuals for at least 2 genera and 3 species of salamanders. Morphological comparison with extinct and extant North American salamanders and body length measurements indicate numerous specimens of Taricha oligocenica, Taricha lindoei, 1 additional, more robust genus containing 1 or more species previously unseen in the Oregon fossil record. Subgenus Palaeotaricha is characterized by a narrow scapular portion of the scapulocoracoid and high to moderately high neural crests that are expanded dorsally and possess a dermal cap, while subgenus Taricha includes all living species and is characterized by a broad scapula and elongate vertebra with low neural crests and no dermal capping plates. The new specimens of T. oligocenica from these sites supports Paleotaricha as a separate and valid subgenera within the Taricha genus based on differences in the scapulocoracoid, vertebrae, and skull. The new specimens of T. lindoei shares features of both extinct and extant subgenera, and may support this species as a transitional form between T. oligocenica and modern members of the genus. The increased resolution of the fossil salamander record in Oregon in volcanic rich shales indicates a transitional open to closed forest affected by volcanic activity.