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GEOREF RECORD

Bacterial residues in coprolite of herbivorous dinosaurs; role of bacteria in mineralization of feces

Thomas C. Hollocher, Karen Chin, Kurt T. Hollocher and Michael A. Kruge
Bacterial residues in coprolite of herbivorous dinosaurs; role of bacteria in mineralization of feces
Palaios (December 2001) 16 (6): 547-565

Abstract

The Cretaceous Two Medicine Formation of northwestern Montana has yielded blocky, calcareous coprolites that contain abundant fragments of conifer wood and were produced by large herbivorous dinosaurs. The coprolites are generally dark gray to black in color due to a dark substance confined chiefly within what originally were the capillaries of tracheid and ray cells of xylem. This substance is a kerogen that consists in part of thin-walled vesicles 0.1-1.3 mu m in diameter. Pyrolysis products of this kerogen are diagnostic of a bacterial origin with a possible contribution from terrestrial plants. The vesicular component is interpreted as the residue of bacterial cells, whereas a second filamentous component, closely associated with the vesicles, may be the residue of an extracellular binding material, such as glycocalyx. At least two episodes of calcification of the coprolite are recognized by manganous cathodoluminescence. The earlier of these infilled the capillary channels of the conifer fragments. Wood cell walls, voids, cracks, and small burrows were filled during the later episode. Microprobe data confirm these results and show that phosphate is sequestered in the capillaries. These observations suggest that bacteria within the capillaries induced initial mineralization of the coprolite, and, in so doing, created barriers that protected organic residues from subsequent destruction. Early onset of mineralization is consistent with the degree of preservation of woody xylem found in the coprolites.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 16
Serial Issue: 6
Title: Bacterial residues in coprolite of herbivorous dinosaurs; role of bacteria in mineralization of feces
Affiliation: Brandeis University, Department of Biochemistry, Waltham, MA, United States
Pages: 547-565
Published: 200112
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 106
Accession Number: 2003-077252
Categories: General paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
N47°30'00" - N48°08'60", W113°01'00" - W111°25'00"
Secondary Affiliation: U. S. Geological Survey, USA, United StatesUnion College, USA, United StatesSouthern Illinois University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200323
Program Name: USGSOPNon-USGS publications with USGS authors
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