BOTANICAL AND INSECT-TRACE FOSSILS FROM A NEW CRETACEOUS LEAF SITE IN GLENROCK, WYOMING

Located in central Wyoming, the Glenrock Exposure of the Lance Formation contains abundant vertebrate bonebeds and microvertebrate assemblages. However, aside from instances of silicified wood, the accompanying floral record of the exposure has been undocumented. Found in 2022, GPM-200 is the first fossil leaf site known from the Glenrock Exposure. More than 170 individual leaf-bearing specimens have been collected, with both angiosperms and gymnosperms represented. Of the former, identified taxa include four members of the family Platanaceae (Plane Trees) and one member of Trochodendraceae and Lauraceae . Of the latter, only one species of the family Cupressaceae is present. More than 10% of the preserved leaves show evidence of insect predation, including feeding traces and coprolites. Among these ichnofossils are specimens referable to gall mites (Eriophyidae), weevils (Curculionidae), and leaf beetles (Chrysomelidae). The faunal and floral composition of GPM-200 is consistent with that known from contemporaneous sites in the Hell Creek of Montana and the Frenchman Formation of Saskatchewan and indicate a mesothermal, subhumid climate with insignificantly variable seasonality.