Abstract Detail

Paleobotany

Update on the Pliocene Gray Fossil Site (Tennessee, U.S.A.) macrofossil flora: Diversity and biogeography.

The early Pliocene Gray Fossil Site (GFS) is an unusual Neogene locality in the southern Appalachian Mountains of eastern Tennessee. While the GFS plant macrofossil flora is diverse, relatively few taxa have been described to date. Formally documented GFS plant macrofossil taxa include Carya tennesseensis Huang et al., Cavilignum pratchettii Siegert & Hermsen (extinct), Corylopsis grisea Quirk & Hermsen, Nyssa grayensis Noll (nom. ined.), Passiflora appalachiana Hermsen, Sinomenium macrocarpum Liu & Jacques, Staphylea levisemia Huang et al., Taxodium (branchlets with leaves), and Vitis (3 species). The following additional taxa are present based upon the occurrence of reproductive structures (cones, fruits, seeds, etc.): Taxodium (seeds), other conifers (cones, cone scales), Betula, Bidens, Caryophyllales, Cyperaceae, Passiflora subgenus Decaloba, Polygonaceae, Quercus, Rubus, Sargentodoxa, Zanthoxylum (2 species), and cf. Xanthium, as well as other unidentified angiosperm taxa. Miscellaneous plant structures not identified to a genus or family also occur (thorns, tendrils), as well as stem fragments of a grass (Poaceae). A fungus in the Xylariaceae (cf. Annulohypoxylon) has also been identified. Based upon the taxa that have so far been studied biogeographically, the macrofossil flora of Gray Fossil Site appears to be made up of genera that are typically represented in the fossil records and the modern floras of Eurasia and North America; only Passiflora comes from a genus with probable origins in the neotropics. Likely modern relatives of GFS species are found today in eastern Asia, eastern North America, and the neotropics. In eastern North America, modern relatives of GFS taxa have differing distributions; they may be widespread (e.g., Passiflora incarnata, related to the GFS species P. appalachiana) or found on the Coastal Plain (e.g., Taxodium), and at least one (cf. Zanthoxylum americanum) has a center of distribution to the north of GFS. Only the unnamed species of Passiflora subgenus Decaloba is most closely related to a group today distributed in the neotropics.

1 - Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, NY, 14850, United States

Keywords:
fossil
Neogene
Cenozoic
Tennessee
eastern North America
biogeography.

Presentation Type: Oral Paper
Number: PB6003
Abstract ID:726
Candidate for Awards:None