41-2 Palynology of the Late Cretaceous Booneville Dinosaur Site, Mississippi, U.S.A.

Session: Paleontology, Stratigraphy, Sediments, and Soils (Posters)

Poster Booth No.: 23

Presenting Author:

Nina Riding

Authors:

Riding, Nina L Baghai¹, Hotton, Carol², Brink, Alyson³, Phillips, George⁴, Starnes, James⁵, Pharr, Olivia Maria Ann⁶

(1) Division of Mathematics and Sciences, Delta State University, Cleveland, MS, USA, (2) Department of Paleobiology, National Museum of Natural History, Washington, DC, USA, (3) School of Biological, Environmental and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA, (4) Paleontology, Mississippi Museum of Natural Science, Jackson, MS, USA, (5) Mississippi Department of Environmental Quality, Office of Geology, Jackson, MS, USA, (6) Division of Mathematics and Sciences, Delta State University, Cleveland, MS, USA,

Abstract:

An important faunal assemblage has been recovered from a site near Booneville, Mississippi that includes the most complete dinosaur remains in Mississippi, consisting of a partial skeleton of an adult hadrosaur, as well as a dentary of a very young hadrosaur, suggesting that it may include a nesting site. Other faunal remains include the teleost Enchodus, sharks including Squalicorax and Scapanorhynchus, crocodilians, toxochelyid sea turtles, the ammonites Menabites and Placenticeras, naticid snails, the saltwater clams Glycymeris lacertosaare and Trigonia sp., and the bivalves Protocardia cf. P. stantoni and Pterotrigonia. The site occurs in the lower Coffee Formation, and consists of interlaminated carbonaceous clays, silts, and fine-grained sands along with teredinid-bored lignitized logs and is interpreted as a tidally influenced estuary. The site includes a rich palynoflora as well, which we describe here. Twenty matrix samples from six sections within a 220 m transect were collected. Twelve of the samples proved to be rich and diverse, with approximately 100 palynomorph taxa so far identified. Based on two 200-grain counts, angiosperms comprise about one third to one half, spores about one third, and gymnosperms about 10% of the assemblage. Algal cysts are also significant, comprising 10-20% of the assemblage; however, dinoflagellates are rare. Species of the biostratigraphically important Late Cretaceous group Normapolles (= Fagales) comprise between 10% and 30% of all angiosperms. Other angiosperms include Holkopollenites, Tschudypollis, Trisectoris, and other tricolporates and tricolpate eudicots of uncertain affinity. Gymnosperms include members of the conifer families Araucariaceae, Cheirolepidiaceae, Cupressaceae and Pinaceae. Spores are quite diverse, and include members of the sphagnum mosses, hepatics, club-mosses, and the fern families Anemiaceae, Dipteridaceae, Gleicheniaceae, Osmundaceae, Schizaeaceae, and Polypodiales. The abundance of fresh-water algal cysts and rarity of dinoflagellates indicate a strong fresh-water influence. A refined biostratigraphic age for the BDS can be proposed based on correlations with comparable palynofloral assemblages in South Carolina. The co-occurrence of Holkopollenites propinquus with a LAD in the earliest mid Campanian and Osculapollis aequalis with a FAD in the late early Campanian places it close to the early-middle Campanian boundary. The abundance of Normapolles forms suggests a warm and perhaps moderately dry climate, but abundant and diverse ferns, lycophytes and bryophytes indicate that much of the local vegetation near the site of deposition was hydrophilic.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

doi: 10.1130/abs/2026SE-12141

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