A PALEOBOTANICAL OVERVIEW OF THE UPPER CRETACEOUS NESLEN FORMATION, WITH A FOCUS ON A NEW SPECIES OF PROTODAMMARA

The Upper Cretaceous (Campanian) Neslen Formation in the Book Cliffs of eastern Utah preserves a fossil assemblage that fills a major latitudinal gap in our understanding of the biogeography Laramidia during the Campanian. Previous work across these depositional basins has primarily focused on the vertebrate assemblage, while a lack of focus on flora has left holes in our understanding of latitudinal distributions, climate, and ecology.

In this contribution, we provide a palaeobotanical overview of the Neslen Formation, including over 800 specimens of conifers, flowering plants, ferns and fern allies. Additionally, we discuss in detail a new species of conifer in the Cupressaceae family. Within this formation, we found over 50 individual ovuliferous scales from a new species of the genus Protodammara. These cone scales are small and flat (1-2 cm), with a narrow petiole and a wide, fan shaped top. Along these structures are resinous canals that run from the petiole to the smooth, curved distal margin. These structures resemble those from Protodammara reimatamoriori found in New Zealand with notable differences, particularly with the shape of the distal end. Previous reconstructions of similar species show that these structures would have flaked off of a central “core” during a fire. Previous research has used Protodammara to reconstruct fire ecology, although the practicality of this type of research in the Neslen Formation has not been investigated. Additionally, despite multiple seasons of fieldwork focused on collecting fossil plants, this species is found only in fissile coalified shales where few other plant fossils have been found. This mode of preservation raises questions about the types of microenvironments in which this plant thrives, as well as how transport and deposition affect the preservation of these cones.