Paper No. 259-3
Presentation Time: 4:20 PM
HYMENOPTERA TRACE FOSSILS FROM THE COPRINISPHAERA ICHNOFACIES IN THE PINK MEMBER OF THE CLARON FORMATION, PANSAUGUNT PLATEAU, BRYCE CANYON NATIONAL PARK, UTAH
Hymenopteran trace fossils are reported from the Claron Formation along the western margin of the Markagunt Plateau in southern Utah, but, to date, there are no published reports of hymenopteran trace fossils from Bryce Canyon National Park. Approximately 400 hymenoptera trace fossils (cocoons) of the Coprinisphaera ichnofacies were recently discovered in the upper part of the lower pink member of the Claron Formation at Bryce Canyon National Park located on the eastern margin of the Paunsaugunt Plateau. Cocoons were found at six different localities. Based on measurements of length and maximum diameter, cocoons cluster in three different size categories, but all have a similar shape. The largest cocoons average 26x14mm into size and are tentatively identified as Eatonichnus utahensis. The second cluster of cocoons average 20x9mm in size and are tentatively identified as E. claronensis. A third cluster of cocoons, averaging 10x3.8mm in size, may represent a different species of Eatonichus. Recent lithologic studies at Bryce Canyon suggest a palustrine deposition for the lower pink member of the Claron Formation, while the upper white member of the Claron is a more typical lacustrine environment. The presence of the hymenopteran trace fossils provides additional support for palustrine depositional system, with a mesic soil condition where there is adequate soil moisture retention year-round.