Pigg, Kathleen B. , Dillhoff, Richard M. , DeVore, Melanie L. .
New diversity among the Trochodendraceae from the Early Eocene McAbee and Early/Middle Eocene One Mile Creek floras, Okanogan Highlands of British Columbia, Canada.
NEWLY recognized fossil infructescences and leaves assignable to the basal eudicot family Trochodendraceae are described from the Early Eocene McAbee and Early/Middle Eocene One Mile Creek sites of British Columbia, Canada. A new Trochodendron infructescence from McAbee is similar to that of extant T. aralioides Sieb. & Zucc. but strongly paniculate rather than racemose as is more typical of the extant taxon. The McAbee fossil is larger and more robust than previously described infructescences associated with T. nastae Pigg, Wehr & Ickert-Bond from Republic, Washington and more similar to both extant Trochodendron and Miocene fossils from Asia and western North America. Associated leaves are similar to those of extant Trochodendron but are larger on average, have teeth on more of the margin and some leaves display short, basal extensions of the lamina ("coat-tails"). They differ from coeval T. nastae leaves in having the typical pinnate, rather than palmate venation. Leaves from One Mile Creek, BC assignable to Tetracentron Oliver are remarkably like those of extant Tetracentron, and firmly establish the presence of this genus in the Eocene Okanogan Highlands. The current study demonstrates further diversity within the Trochodendraceae. Extinct forms with palmate leaves and undersized infructesences co-existed with quite modern-appearing fruits and leaves in the Early Eocene of northwestern North America.
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1 - Arizona State University, School of Life Sciences, P.O. Box 874501, Tempe, Arizona, 85287-4501, USA
2 - Evolving Earth Foundation, PO Box 2090, Issaquah, Washington, 98027, USA
3 - Georgia College & State University, Biological & Environmental Sciences, 135 Herty Hall, Campus Box 81, Milledgeville, Georgia, 31061, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, August 1st, 2006
Time: 9:45 AM