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A unique bivalve–algae life assemblage from the Bear Gulch Limestone (Upper Mississippian) of central Montana

Published online by Cambridge University Press:  19 May 2016

Christopher A. McRoberts  and
George D. Stanley Jr.
Christopher A. McRoberts
Affiliation:
Department of Geology, University of Montana, Missoula 59812
George D. Stanley Jr.
Affiliation:
Department of Geology, University of Montana, Missoula 59812
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Abstract

A single limestone slab is described from the Mississippian Bear Gulch Limestone of central Montana containing more than 100 bivalves, including Caneyella sp. and ?Ptychopteria (Actinopteria) sp., attached in original life positions along an 80-cm-long ?brown alga. The assemblage provides clear evidence of life position and choice of substrate for these pterioids. The bivalves increase in size, and appear to be radially disposed in their attachment sites, along the loosely coiled “kelp-like” alga, indicating little postmortem transport and current activity. The bivalve population is interpreted as living on an algal thallus that was either planktonic or attached to the substrate. Observations and comparisons with modern bivalve—seaweed associations support either view. Evidence for local anoxic conditions and stagnant water help explain the superb preservation and confirm past interpretations of the Bear Gulch Limestone.

Type
Research Article
Information
Journal of Paleontology , Volume 63 , Issue 5 , September 1989 , pp. 578 - 581
Copyright
Copyright © The Paleontological Society 

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References

Conway Morris, S. 1979. Conodontophorids or conodontophages? A review of the evidence on the “Conodontochordates” from the Bear Gulch Limestone (Namurian) of Montana, U.S.A. Comptes Rendus, 9th International Carboniferous Conference, 5:473–480.Google Scholar
Cox, R. S. 1986. Preliminary report on the age and palynology of the Bear Gulch Limestone (Mississippian, Montana). Journal of Paleontology, 60:952–956.CrossRefGoogle Scholar
Horner, J. R., and Lund, R. 1979. Biotic distribution and diversity in the Bear Gulch Limestone of central Montana. Comptes Rendus, 9th International Carboniferous Conference, 5:437–442.Google Scholar
Kauffman, E. G. 1975. Dispersal and biostratigraphic potential of Cretaceous benthonic Bivalvia in the Western Interior, p. 163–194. In Caldwell, W. G. (ed.), The Cretaceous System in the Western Interior of North America. Geological Association of Canada Special Paper 13.Google Scholar
Kauffman, E. G. 1981. Ecological reappraisal of the German Posidienschiefer (Toarcian) and the stagnant basin model, p. 311–381. In Gray, J., Boucot, A. J., and Berry, W. B. N. (eds.), Communities of the Past. Hutchinson Ross Publishing Company, Stroudsburg, Pennsylvania.Google Scholar
Melton, W. G. 1983. Notes on the paleoecology of the Bear Gulch Limestone, central Montana, U.S.A. Comptes Rendus, 10th International Carboniferous Conference, 4:257–260.Google Scholar
Mukai, H. 1971. The phytal animals on the thalli of Sargassum serratifolium in the Sargassum region, with reference to their seasonal fluctuations. Marine Biology, 8:170–172.CrossRefGoogle Scholar
Mukai, H. 1976. Molluscs on the thalli of Sargassum serratifolium. Japanese Journal of Malacology (VENUS), 35:119–133.Google Scholar
Schram, F. R. 1979. Worms of the Mississippian Bear Gulch Limestone of central Montana, U.S.A. Transactions of the San Diego Society of Natural History, 19:107–120.Google Scholar
Mukai, H., and Horner, J. R. 1978. Crustacea of the Mississippian Bear Gulch Limestone of central Montana. Journal of Paleontology, 52:394–406.Google Scholar
Stewart, W. N. 1985. Paleobotany and the Evolution of Plants. Cambridge University Press, New York.Google Scholar
Williams, L. A. 1983. Deposition of the Bear Gulch Limestone: a Carboniferous Plattenkalk from central Montana. Sedimentology, 30:843–860.CrossRefGoogle Scholar