| Abstract Detail
Paleobotany Hermsen, Elizabeth [1]. Seeds of Zanthoxylum (Rutaceae) from the Pliocene Gray Fossil Site, Tennessee, U.S.A. Gray Fossil Site (in Gray, near Johnson City, Tennessee, U.S.A.) is an early Pliocene fossil locality that yields plant and vertebrate remains preserved in the sediments of an ancient sinkhole lake. The flora of the site includes both microfossils and macrofossils, which overlap only partially in their taxonomic composition. So far, eight angiosperm genera have been described from reproductive macrofossil material, whereas the conifer Taxodium has been documented from foliage. Most of the GFS plant macrofossil taxa described so far have primarily Laurasian (North American-European-Asia) fossil and modern distributions, with one genus (Passiflora) representing an unusual Neotropical component. In this study, I describe Zanthoxylum seeds. The seeds are roughly oval in lateral view, small (up to about 5.1 mm long), and slightly compressed. The seed surface is shiny and devoid of wrinkles, ridges, spines, or other protuberances, but is covered by minute circular pits. The large hilum is roughly rectangular to triangular in shape and bordered by a raised lip; it is variable in length relative to the overall length of the seed. The hilum occurs above a raphal crest, which may be distinct or indistinct. The pitted but otherwise smooth surface of the GFS Zanthoxylum seeds is similar to that found on seeds of the modern species Zanthoxylum americanum, which is native to the eastern United States. Extant Zanthoxylum includes over 200 species and is pantropical in distribution, although Z. americanum and some other species occur in temperate regions of the northern hemisphere. Fossil Zanthoxylum seeds are known from North America, Europe, and Asia. The GFS Zanthoxylum species may thus fit both the Laurasian biogeographic pattern and the Neotropical pattern documented from other plant macrofossil taxa found at GFS.
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1 - Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, NY, 14850, United States
Keywords:
Rutaceae
Pliocene
Fossil
Zanthoxylum
North America.
Presentation Type: Oral Paper
Session: PL7, Paleobotany: Mesozoic/Cenozoic Paleobotany
Location: /
Date: Thursday, July 22nd, 2021
Time: 2:15 PM(EDT)
Number: PL7008
Abstract ID:872
Candidate for Awards:None |
