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Abstract Detail

Paleobotanical Section

Stull, Gregory W. [1], Manchester, Steven  [1].

Geographic and stratigraphic pervasiveness of the Phytocreneae (Icacinaceae) in the Paleogene of western North America.

The Phytocreneae are a tribe of lianas and scrambling shrubs within the pantropical lamiid family Icacinaceae. The tribe, which is exclusively Paleotropical today, includes four extant genera: Miquelia (4 spp.), Phytocrene (11 spp.), Pyrenacantha (ca. 30 spp., including the subsumed genera Chlamydocarya and Polycephalium), and Stachyanthus (2 spp.). The first two genera are now restricted to Indo-Malesia, Pyrenacantha is distributed across the Paleotropics with its center of diversity in Africa, and Stachyanthus is restricted to West Africa. Fruits of the tribe are readily recognizable and well documented in the fossil record due to their distinctive woody endocarps with pitted surfaces, generally corresponding to tuberculate protrusions into the locule (the morphology of which varies among the taxa). Fossil occurrences of the tribe are known mostly from the Paleogene of Europe and North America, representing the extant genera Phytocrene and Pyrenacantha, as well as an extinct genus, Palaeophytocrene. Our summary of the Phytocreneae fossil record highlights new and poorly documented Paleogene fossils from interior and more coastal floras of western North America. These include endocarp impressions of cf. Pyrenacantha from the Eocene Green River Formation and the Kisinger Lakes floras of Colorado and Wyoming, and of Palaeophytocrene from the early-middle Eocene Chalk Bluffs and Republic floras of California and Washington, the late Eocene La Porte flora of California, and finally, the early Oligocene Bridge Creek flora of Oregon. We compare these fossils to previously documented fossils of the tribe (e.g., from Paleocene floras of the Great Plains, and Eocene floras of British Columbia, England, Oregon, and Tennessee), as well as to fruits of numerous modern representatives of Phytocreneae, to highlight their systematic affinities. The prevalence of Phytocreneae fossils in Paleogene floras of the Northern Hemisphere (and especially western North America) is biogeographically and climatically significant given the present-day confinement of this clade to rainforests of the Paleotropics.

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1 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA

North America

Presentation Type: Oral Paper:Papers for Sections
Session: 8
Location: Whitewater/Grove
Date: Monday, July 28th, 2014
Time: 1:30 PM
Number: 8015
Abstract ID:394
Candidate for Awards:Isabel Cookson Award

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