O'Leary, Elizabeth , Manchester, Steven R. , Dilcher, David .
A Redetermination of Terminalia (Combretaceae) fruits from the Eocene of southeastern North America.
One of the most common winged fruit types in the Eocene clay deposits of the Claiborne Formation in western Tennessee and Kentucky are being studied to reevaluate its taxonomic position. Referred to previously as Carpolithus prangosoides Berry (1916) and Terminalia vera Berry (1926), the fruits were initially interpreted either as a capsule or as a biwinged fruit. More specimens, preserved in various orientations within the clay, are now available, providing for a more informed assessment of their morphology. It is now clear that the fruits are indehiscent and have multiple wings. Obliquely and transversely fractured specimens reveal that five wings radiate laterally from a fusiform, longitudinally striate, central axis. The wing venation is oriented about 30 degrees from the fruit's central axis with loops forming a reticulum. We do not know about the pedicel, styles or locule condition. But the available characters, including the number and position of wings and their venation allows for detailed comparison with extant fruits of similar form. Although this species was assigned to the Combretaceae based on its lateral wings, detailed comparison of wing venation distinguishes the fossil from this family. The wing venation of modern Terminalia and other samaroid Combretaceae is much finer, and less prominently reticulate than Carpolithus prangosoides. Additionally the veins fan outward rather than upward from the fruit's central axis. We therefore, reject the identification of Carpolithus prangosoides to the Combretaceae. The taxonomic affinities are best considered uncertain with our present state of knowledge.
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1 - University of Florida, Botany, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
2 - Florida Museum of Natural History, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611, USA
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 2:45 PM