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Catastrophic death assemblage of Chelomophrynus bayi (Anura, Rhinophrynidae) from the Middle Eocene Wagon Bed Formation of central Wyoming

Published online by Cambridge University Press:  20 May 2016

Amy C. Henrici
Affiliation:
Section of Vertebrate Fossils, The Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, Pennsylvania 15213
Anthony R. Fiorillo
Affiliation:
Museum of Paleontology, University of California, Berkeley 94720

Abstract

A unique monospecific bonebed of rhinophrynid anurans was recently discovered in the Wagon Bed Formation (Middle Eocene, Uintan), Hot Springs County, Wyoming. The bonebed occurs on a single bedding plane within a thin sandstone layer. This unit is part of a nearshore facies of a calcium carbonate-rich lake in which the water was warm, shallow, and quiet at the site of the mortality layer.

A representative area of this bonebed, approximately 450 square centimeters in size, provides the basis for this taphonomic and paleoecologic study. This area contains approximately 600 bones and at least 19 individuals are represented. Skeletons are nearly completely disarticulated but somewhat associated, bone modification features are absent, a slight preferred orientation of the linear bones is present, and many of the lighter, less dense skeletal elements are underrepresented. Scavengers probably contributed to disarticulation of the skeletons. Bone depletion occurred by a combination of the action of scavengers, weak currents, and the sloughing off of body parts as the carcasses floated. The assemblage was not subjected to extensive winnowing by currents.

All of the specimens within this assemblage represent young adults. Because the frogs are all of the same ontogenetic age and the deposit shows no signs of time averaging, the assemblage is interpreted as the result of catastrophic death, possibly by disease, of one age class. Either a population of frogs inhabited the site where the mortality layer formed or the carcasses floated into it.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

Andrews, P. 1990. Owls, caves and fossils. Natural History Museum Publications, London, 231 p.Google Scholar
Andrews, P., and Nesbit-Evans, E. M. 1983. Small mammal bone accumulations produced by mammalian carnivores. Paleobiology 9:289307.CrossRefGoogle Scholar
Bay, K. W. 1969. Stratigraphy of Eocene sedimentary rocks in the Lysite Mountain area, Hot Springs, Fremont, and Washakie Counties, Wyoming. Unpubl. Ph.D. dissertation, University of Wyoming, Laramie, 181 p.Google Scholar
Behrensmeyer, A. K. 1975. Taphonomy and paleoecology of Plio-Pleistocene vertebrate assemblages east of Lake Rudolph, Kenya. Bulletin of the Museum of Comparative Zoology, 146(10):473578.Google Scholar
Behrensmeyer, A. K. 1978. Taphonomic and ecologic information from bone weathering. Paleobiology, 4:150162.Google Scholar
Behrensmeyer, A. K., Gordon, K. D., and Yanagi, G. T. 1986. Trampling as a cause of bone surface damage and pseudocutmarks. Nature, 319:768771.Google Scholar
Bently, P. J. 1966. Adaptations of Amphibia to arid environments. Science, 152:619623.Google Scholar
Berggren, W. A., Kent, D. V., Flynn, J. J., and Van Couvering, J. A. 1985. Cenozoic geochronology. Geological Society Bulletin, 96:14071418.Google Scholar
Bonnichsen, R., and Sorg, M. H. (eds.). 1989. Bone Modification. Center for the Study of the First Americans, Institute for Quaternary Studies, University of Maine, Orono, 535 p.Google Scholar
Brattstrom, B. H. 1963. A preliminary review of the thermal requirements of amphibians. Ecology, 44:238255.Google Scholar
Brattstrom, B. H. 1979. Amphibian temperature regulation studies in the field and laboratory. American Zoologist, 19:345356.CrossRefGoogle Scholar
Brattstrom, B. H., and Lawrence, P. 1962. The rate of thermal acclimation in anuran amphibians. Physiological Zoology, 35:148156.Google Scholar
Dodson, P. 1971. Sedimentology and taphonomy of the Oldman Formation (Campanian), Dinosaur Provincial Park, Alberta (Canada). Palaeogeography, Palaeoclimatology, Palaeoecology, 10:2174.Google Scholar
Dodson, P. 1973. The significance of small bones in paleoecological interpretation. Contributions to Geology, University of Wyoming, 12:1519.Google Scholar
Duellman, W. E., and Trueb, L. 1986. Biology of Amphibians. McGraw-Hill Inc., New York, 670 p.Google Scholar
Dusi, J. L. 1949. The natural occurrence of “Redleg,” Pseudomonas hydrophila, in a population of American toads, Bufo americanus. Ohio Journal of Science, 49:7071.Google Scholar
Elder, R. L. 1985. Principles of aquatic taphonomy with examples from the fossil record. Unpubl. Ph.D. dissertation, University of Michigan, Ann Arbor, 336 p.Google Scholar
Fiorillo, A. R. 1984. An introduction to the identification of trample marks. Current Research, University of Maine, 1:4748.Google Scholar
Fiorillo, A. R. 1987. Trample marks: caution from the Cretaceous. Current Research in the Pleistocene, 4:7375.Google Scholar
Fiorillo, A. R. 1988a. Taphonomy of Hazard Homestead Quarry (Ogallala Group), Hitchcock County, Nebraska. Contributions to Geology, University of Wyoming, 26:5797.Google Scholar
Fiorillo, A. R. 1988b. A proposal for graphic presentation of orientation data from fossils. Contributions to Geology, University of Wyoming, 26:14.Google Scholar
Fiorillo, A. R. 1989a. Taphonomy and paleoecology of the Judith River Formation (Late Cretaceous) of south central Montana. Unpubl. Ph.D. dissertation, University of Pennsylvania, Philadelphia, 283 p.Google Scholar
Fiorillo, A. R. 1989b. An experimental study of trampling: implications for the fossil record, p. 6172. In Bonnichsen, R. and Sorg, M. H. (eds.), Bone Modification. Center for the Study of the First Americans, University of Maine, Orono.Google Scholar
Fiorillo, A. R. 1990. Utilization of prey bones by predatory dinosaurs. Journal of Vertebrate Paleontology, Abstracts of Papers, 10(supplement to no. 3):22A.Google Scholar
Fiorillo, A. R. 1991a. Taphonomy and depositional setting of Careless Creek Quarry (Judith River Formation), Wheatland County, Montana, U.S.A. Palaeogeography, Palaeoclimatology, Palaeoecology, 81:281311.Google Scholar
Fiorillo, A. R. 1991b. Pattern and process in bone modification. Anthropologie, 29:157161.Google Scholar
Folk, R. L. 1959. Practical petrographic classification of limestones. American Association of Petroleum Geologists Bulletin, 43:138.Google Scholar
Foster, M. S., and McDiarmid, R. W. 1983. Rhinophrynus dorsalis, p. 419421. In Janzen, D. H. (ed.), Costa Rican Natural History. University of Chicago Press, Chicago, Illinois.Google Scholar
Grande, L. 1984. Paleontology of the Green River Formation, with a review of the fish fauna. Geological Survey of Wyoming Bulletin, 63:1333.Google Scholar
Hay, R. L. 1956. Pitchfork Formation, detrital facies of early basic breccia, Absaroka Range, Wyoming. American Association of Petroleum Geologists Bulletin, 40:18631898.Google Scholar
Haynes, G. 1980. Prey bones and predators: potential ecologic information from analysis of bone sites. Ossa, 7:7597.Google Scholar
Henrici, A. C. 1991. Chelomophrynus bayi (Amphibia, Anura, Rhinophrynidae) a new genus and species from the middle Eocene of Wyoming: ontogeny and relationships. Annals of the Carnegie Museum, 60:97144.Google Scholar
Hill, A. 1979. Disarticulation and scattering of mammal skeletons. Paleobiology, 5:261274.Google Scholar
Hill, A., and Behrensmeyer, A. K. 1984. Disarticulation patterns of some modern East African mammals. Paleobiology, 10:366376.CrossRefGoogle Scholar
Hunsaker, D., and Potter, F. E. 1960. “Red-leg” in a natural population of amphibians. Herpetologica, 16:285286.Google Scholar
Hunt, R. M. Jr. 1978. Depositional setting of a Miocene mammal assemblage, Sioux County, Nebraska (U.S.A.). Palaeogeography, Palaeoclimatology, Palaeoecology, 24:152.Google Scholar
Korth, W. W. 1979. Taphonomy of microvertebrate fossil assemblages. Annals of the Carnegie Museum, 48:235285.Google Scholar
Lawton, R. 1977. Taphonomy of Dinosaur Quarry, Dinosaur National Monument. Contributions to Geology, University of Wyoming, 15:119126.Google Scholar
Love, J. D. 1939. Geology along the southern margin of the Absaroka Range, Wyoming. Geological Society of America Special Paper, 20:1134.Google Scholar
Love, J. D. 1964. Uraniferous phosphatic lake beds of Eocene age in intermontane basins of Wyoming and Utah. U.S. Geological Survey Professional Paper, 474-E:166.Google Scholar
Love, J. D., and Christiansen, A. C. 1985. Geologic map of Wyoming. Geologic Survey of Wyoming.Google Scholar
Love, J. D., Christiansen, A. C., Earle, T. L., and Jones, R. W. 1978. Preliminary geologic map of the Arminto 1 × 2 quadrangle, central Wyoming. U.S. Geological Survey, Open-file Report 78–1089.Google Scholar
MacGinitie, H. D. 1969. The Eocene Green River flora of northwestern Colorado and northeastern Utah. University of California Publications in Geological Sciences, 83:1140.Google Scholar
MacGinitie, H. D. 1974. An early middle Eocene flora from the Yellowstone-Absaroka volcanic province, northwestern Wind River Basin, Wyoming. University of California Publications in Geological Sciences, 108:1103.Google Scholar
McKenna, M. C. 1962. Collecting small fossils by washing and screening. Curator, 5:221235.Google Scholar
Nevo, E. 1968. Pipid frogs from the early Cretaceous of Israel and pipid evolution. Bulletin Museum Comparative Zoology, 136:255318.Google Scholar
Nyman, S. 1986. Mass mortality in larval Rana sylvatica attributable to the bacterium, Aeromonas hydrophila. Journal of Herpetology, 20:196201.Google Scholar
Potter, P. E., and Pettijohn, F. J. 1977. Paleocurrents and Basin Analysis, 2nd edition. Springer-Verlag, New York, 425 p.Google Scholar
Pratt, A. 1989. Taphonomy of the microvertebrate fauna from the early Miocene Thomas Farm locality, Florida (U.S.A.). Palaeogeography, Palaeoclimatology, Palaeoecology, 76:125151.CrossRefGoogle Scholar
Rohrer, W. L., and Smith, J. W. 1969. Tatman Formation, p. 4954. In Wyoming Geological Association Guidebook, Twenty-first Annual Field Conference.Google Scholar
Saunders, J. J. 1977. Late Pleistocene vertebrates of the western Ozark highland, Missouri. Reports of Investigations No. 33, Illinois State Museum, Springfield, Illinois, 118 p.Google Scholar
Schafer, W. 1972. Ecology and Palaeoecology of Marine Environments. University of Chicago Press, Chicago, Illinois, 568 p.Google Scholar
Schmid, W. D. 1982. Survival of frogs in low temperatures. Science, 215:697698.CrossRefGoogle Scholar
Shipman, P. 1981. Life History of a Fossil, An Introduction to Taphonomy and Paleoecology. Harvard University Press, Cambridge, Massachusetts, 222 p.Google Scholar
Spinar, Z. V. 1972. Tertiary Frogs from Central Europe. W. Junk, The Hague, 286 p.Google Scholar
Thaden, R. E. 1979. Geologic map of the Lysite quadrangle, showing chronolithofacies and coal beds in the Wind River Formation, Fremont County, Wyoming. U.S. Geological Survey Geologic Quadrangle Map, GQ-1511, scale 1:24,000.Google Scholar
Thaden, R. E. 1980a. Geologic map of the De Pass quadrangle, Fremont and Hot Springs Counties, Wyoming. U.S. Geological Survey Geologic Quadrangle Map, GQ-1526, scale 1:24,000.Google Scholar
Thaden, R. E. 1980b. Geologic map of the Guffy Peak quadrangle, showing chronolithofacies in the Wind River Formation, Fremont and Hot Springs Counties, Wyoming. U.S. Geological Survey Geologic Quadrangle Map, GQ-1527, scale 1:24,000.Google Scholar
Thaden, R. E. 1980c. Geologic map of the Birdseye Pass quadrangle, showing chronolithofacies and coal beds in the Wind River Formation, Fremont and Hot Springs Counties, Wyoming. U.S. Geological Survey Geologic Quadrangle Map, GQ-1537, scale 1:24,000.Google Scholar
Thaden, R. E. 1980d. Geologic map of the Gates Butte quadrangle, showing chronolithofacies, and coal beds in the Wind River Formation, Fremont County, Wyoming. U.S. Geological Survey Quadrangle Map, GQ-1538, scale 1:24,000.Google Scholar
Thaden, R. E. 1980e. Geologic map of the Picard Ranch quadrangle, showing chronolithofacies and coal beds in the Wind River Formation, Fremont County, Wyoming. U.S. Geological Survey Quadrangle Map, GQ-1539, scale 1:24,000.Google Scholar
Thaden, R. E. 1981. Geologic map of the Arapahoe Butte quadrangle, Fremont and Hot Springs Counties, Wyoming. U.S. Geological Survey Geologic Map, GQ-1558, scale 1:24,000.Google Scholar
Toots, H. 1965a. Orientation and distribution of fossils as environmental indicators, p. 219229. In Wyoming Geological Association Guidebook, Nineteenth Annual Field Conference.Google Scholar
Toots, H. 1965b. Sequence of disarticulation in mammalian skeletons. Contributions to Geology, University of Wyoming, 4:3739.Google Scholar
Tourtelot, H. A. 1948. Tertiary rocks in the northeastern part of the Wind River Basin, Wyoming, p. 112124. In Wyoming Geological Association Guidebook, Third Annual Field Conference.Google Scholar
Tourtelot, H. A. 1957. Geology, Part 1 of the geology and vertebrate paleontology of upper Eocene strata in the northeastern part of the Wind River Basin, Wyoming. Smithsonian Miscellaneous Collections, 134(4):127.Google Scholar
Van Houten, F. B. 1964. Tertiary geology of the Beaver Rim area, Fremont and Natrona Counties, Wyoming. U.S. Geological Survey Bulletin, 1164:199.Google Scholar
Voorhies, M. R. 1969. Taphonomy and population dynamics of the early Pliocene vertebrate fauna, Knox County, Nebraska. Contributions to Geology, University of Wyoming, Special Paper 1, 69 p.Google Scholar
Worthylake, K. M., and Hovingh, P. 1989. Mass mortality of salamanders (Ambystoma tigrinum) by bacteria (Acinetobacter) in an oligotrophic seepage mountain lake. Great Basin Naturalist, 49:364372.Google Scholar
Yen, T. C. 1946. Eocene nonmarine gastropods from Hot Springs County, Wyoming. Journal of Paleontology, 20:495500.Google Scholar