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Abstract Detail



Paleobotany

Stults, Debra [1], Axsmith, Brian [2], McNair, Daniel [3], Alford, Mac [4].

Preliminary investigation of a diverse Miocene megaflora from the Hattiesburg Formation, Mississippi.

Our understanding of Miocene plant evolution in the southeastern United States is hampered by the rarity of productive sites with well-preserved fossils. Berry (1916) briefly described a poorly preserved palm (Sabalites apalachicolensis) and leaves of Ulmus floridana from the Miocene Hattiesburg Formation in southeastern Mississippi. In 1944, a few plant fossils from the Hattiesburg Formation were identified by Roland Brown as a probable Taxodium (possibly T. distichum), Salix, either Morus or Celtis, and fragments of some type of monocot. None of these fossils were described in detail or figured. Recently, an extensive megaflora has been recovered from the upper part of the Hattiesburg Formation along the Bowie River in Mississippi. Ferns are represented by specimens of Salvinia with attached sporocarps, a probable Woodwardia s.l. based on a pinnatifid frond, and a possible Osmunda cf. regalis pinna. Conifers are represented by branchlets of Taxodium with preserved cuticles. Angiosperms include leaves attributable to the Lauraceae based on venation pattern, oil bodies in the mesophyll, and paracytic stomata. Platanus (Platanaceae) is commonly associated with palms, and recognized from leaves, fruits, and large logs. Leaflets of Sambucus (Adoxaceae) are common. Cercis (Fabaceae) is recognized from leaves with palmate venation and pulvini. Leaves of Quercus (Fagaceae) sections Lobatae and Quercus have been recovered. The Juglandaceae include fruits of Juglans section Rhysocaryon, and two species of Carya section Apocarya. Morus (Moraceae) is known from leaves, as are Populus and Salix (Salicaceae). Of particular interest is an endocarp of Sargentodoxa (Lardizabalaceae), being the first record of this Chinese endemic from the southeastern coastal plain, and only the third occurrence in North America. Monocots include Cyperus (Cyperaceae) based on spikelets with achenes, and two types of palm (Arecaceae). One type of palm is costapalmate, the other palmate. Two palmate specimens have robust, recurved spines on the petiole, the first record of this type of fossil palm from North America. Ongoing research is focused on refining identifications, paleoclimate, and constraining the Miocene age of the site. The Hattiesburg Formation megaflora is now one of the most extensive in eastern North America, and along with the Brandon Lignite of Vermont, the Alum Bluff flora of Florida, the Brandywine flora of Maryland, and the Gray Fossil site of Tennessee, helps to fill a major temporal and biogeographic gap in our understating of Miocene plant evolution in eastern North America.


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1 - University of South Alabama, Biology, Mobile, Alabama
2 - University Of South Alabama, Biology Department, 5871 USA Drive North, Room 124, MOBILE, AL, 36688-0002, USA
3 - The Center for Plant Diversity, Plant Sciences, Mail Stop 7, One Shields Ave, Davis, California, 95616
4 - University Of Southern Mississippi, Department Of Biological Sciences, 118 COLLEGE DRIVE #5018, HATTIESBURG, MS, 39406-0001, USA

Keywords:
Hattiesburg Formation
Miocene
Mississippi
Megaflora.

Presentation Type: Oral Paper
Session: 28, Mesozoic to Pleistocene Paleobotany
Location: 102/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 4:00 PM
Number: 28010
Abstract ID:191
Candidate for Awards:None


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