The U.S. Gulf Coast has an extensive but poorly dated paleobotanical record. A fossil locality behind the former Red Hot Truck Stop in Meridian, Mississippi, is well-known for its unusually rich biota of late Paleocene and early Eocene mammals, fish, snakes, mollusks, and plants. The latter include palynomorphs, fruits, and leaves, which are found in the basal Bashi Formation and are studied here for the first time. Though generally not well-preserved, the Red Hot leaf flora is significant because it is reliably dated to the first ~1.6 million years of the Eocene and possibly lies within the Paleocene-Eocene Thermal Maximum; in contrast, nearly all other Eocene Gulf Coast macrofloras are middle Eocene or uncertain in age.

We recognize 18 leaf species and morphotypes, including Lygodium kaulfussi (a climbing fern), and representatives of Lauraceae (laurel family), Myrtaceae (guava family), Fabaceae (legumes), Platycarya (Juglandaceae, walnut family), Rhus (Anacardiaceae, sumac family), and a new genus and species of Ochnaceae (ochna family), all consistent with a tropical to subtropical climate. Additionally, two dispersed cuticle morphotypes are described that probably represent a monocot and a liverwort. The occurrence of Platycarya is the first macrofossil record of this Eocene index taxon from the eastern USA and corroborates pollen occurrences from the same strata. The Ochnaceae specimens are currently the only reliable leaf fossils of this distinctly tropical group with ~30 genera and ~500 species today; due to their significance, we assign them to a new taxon, Rhabdophyllites diapyros gen. et sp. nov. Most of the recognizable plant taxa are present at, or near, this time in the well-dated sequences of the Rocky Mountain region, indicating their wide North American distribution. The Red Hot flora shows the potential to build a well-dated record of Paleogene floras on the Gulf Coast, improving understanding of plant migration and evolution.

Daniel R. Danehy. Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A.
Current address: Department of Geological Sciences, Southern Methodist University, PO Box 750395, Dallas, Texas, 75275. U.S.A.
Peter Wilf. Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A.
Stefan A. Little. Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, U.S.A.

KEY WORDS: Bashi Formation; Gulf Coast; new genus; new species; Ochnaceae; Rhabdophyllum; Rhabdophyllites diapyros; Platycarya; cuticle; Wasatchian; Eocene; PETM

PE Article Number: 10.3.17A
Copyright: Paleontological Society December 2007
Submission: 11 June 2007. Acceptance: 29 November 2007