Abstract Detail

Paleobotany

DeVore, Melanie [1], Nyandwi, Alphonse [2], Uhawenimana, Pasteur [2], Eckardt, Winnie [3], van der Hoek, Yntze [3], Bizura, Elias [4], Pigg, Kathleen [5].

Foliar features associated with mammal herbivory in the Paleogene.

Anatomical and morphological traits of living plants can serve as proxies for modern, abiotic environments. Such traits as leaf physiognomy, wood anatomy and stomatal index have been used by paleobotanists to interpret paleoclimate. Biotic interactions, including fungal symbioses, insect herbivory and mammal dietary analyses based on dental morphology, have been the subject of numerous studies. Studies of herbivory have focused largely on plant influence on animals. What we have not examined carefully in the fossil record are indications of the plant's response to herbivores. Plant’s mechanical responses would be reflected in its leaf morphology and anatomical features. For example, the co-occurrence of large mammalian herbivores and plant fossils with defense morphologies would be of particular interest in reconstructing Paleogene communities. Over the last five years, we have begun comparison of the extant biota of the Virunga Mountains in eastern central Africa to understand past mammal herbivory. The Virungas serve as an analogue for early Eocene upland lacustrine environments of the Okanogan Highlands, British Columbia, Canada and Republic, WA, USA. Plants in the Virungas today have survived strong selective pressure from megafauna. We would expect to find indications of similar foliar responses to herbivory in the fossil record. To date we have documented stinging trichomes in fossil leaves assignable to tribe Urticeae (Urticaceae). Also known from the same localities are sumac leaves (Rhus Anacardiaceae) that show distinctive glands that document the Paleogene presence of foliar irritants, like those of the modern-day relative poison ivy [Toxicodendron radicans (L.) Kuntze]. Previous studies have demonstrated the coevolution of plant mechanical defenses with frugivorous. The coexistence of folivores with leaves with distinctive defense structures such as stinging trichomes provide us with valuable characters and increase our understanding of plant responses to megafauna during the Paleogene.

1 - Georgia College & State University, Biological And Environmental Sciences, Campus Box 081, Milledgeville, GA, 31061, United States
2 -
3 - The Dian Fossey Gorilla Fund International
4 - University of Rwanda
5 - Arizona State University, School Of Life Sciences, PO Box 874501, Tempe, AZ, 85287, United States

Keywords:
herbivory
Plant Defenses
Okanagan Highlands
Virunga Mountains
Eocene.

Presentation Type: Oral Paper
Number: PB6002
Abstract ID:508
Candidate for Awards:None