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Testate amoebae in the Neoproterozoic Era: evidence from vase-shaped microfossils in the Chuar Group, Grand Canyon

Published online by Cambridge University Press:  08 February 2016

Susannah M. Porter  and
Andrew H. Knoll
Susannah M. Porter
Affiliation:
Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138. E-mail: sporter@oeb.harvard.edu
Andrew H. Knoll
Affiliation:
Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138. E-mail: sporter@oeb.harvard.edu
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Abstract

Vase-shaped microfossils (VSMs) occur globally in Neoproterozoic rocks, but until now their biological relationships have remained problematic. Exceptionally preserved new populations from the uppermost Chuar Group, Grand Canyon, Arizona, display details of morphology and taphonomy that collectively point to affinities with the testate amoebae. The fossils are tear-shaped tests, ∼20–300 μm long and ∼10–200 μm wide, that are circular in transverse section, expand aborally toward a rounded or slightly pointed pole, and taper orally toward a “neck” that ends in a single aperture. Apertures may be circular, hexagonal, triangular, or crenulate, and may be rimmed by a distinct collar. Approximately 25% of the Chuar VSMs are curved, such that the oral and aboral poles do not lie opposite each other. Tests are preserved as mineralized casts and molds, commonly coated with organic debris or iron minerals, but they were originally composed of nonresistant organic matter. Approximately 1% have a “honeycomb-patterned” wall attributable to the original presence of mineralized scales whose bases were arranged regularly in the test wall. Scale-bearing testate amoebae, such as members of the Euglyphidae, are essentially identical to the honeycomb VSMs, and a close relationship between other Grand Canyon VSMs and additional testate amoebae, both lobose and filose, is likely. The VSM population therefore most likely represents a multispecies assemblage whose spatial association reflects a common habitat and/or taphonomic circumstances that favor test preservation. The assignment of these fossils to the testate amoebae strengthens the case for a major diversification of eukaryotic organisms by mid-Neoproterozoic times and, more significantly, provides the earliest morphological evidence for heterotrophic eukaryotes in marine ecosystems.

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Articles
Information
Paleobiology , Volume 26 , Issue 3 , Summer 2000 , pp. 360 - 385
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Copyright © The Paleontological Society 

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References

Literature Cited

Allison, C. W., and Awramik, S. M. 1989. Organic-walled microfossils from the earliest Cambrian or latest Proterozoic Tindir Group rocks, Northwest Canada. Precambrian Research 43:253–294.CrossRefGoogle Scholar
Anbar, A. N., and Knoll, A. H. 1999. Trace metal limitation of primary production 1.85–1.25 Ga. American Geophysical Union, 1999 fall meeting, Abstracts 80:F49.Google Scholar
Baldauf, S. L., and Doolittle, W. F. 1997. Origin and evolution of the slime molds (Mycetozoa). Proceedings of the National Academy of Sciences USA 94:12007–12012.CrossRefGoogle ScholarPubMed
Bengtson, S., ed. 1994. Early life on Earth (Nobel Symposium No. 84). Columbia University Press, New York.Google Scholar
Berner, R. A., and Raiswell, R. 1984. C/S method for distinguishing freshwater from marine sedimentary rocks. Geology 12:365–368.2.0.CO;2>CrossRefGoogle Scholar
Bhattacharya, D., and Weber, K. 1997. The actin gene of the glaucocystophyte Cyanophora paradoxa: analysis of the coding region and introns, and an actin phylogeny of eukaryotes. Current Genetics 31:439–446.CrossRefGoogle Scholar
Binda, P. L., and Bokhari, M. M. 1980. Chitinozoanlike microfossils in a late Precambrian dolostone from Saudi Arabia. Geology 8:70–71.2.0.CO;2>CrossRefGoogle Scholar
Bloeser, B. 1985. Melanocyrillium, a new genus of structurally complex Late Proterozoic microfossils from the Kwagunt Formation (Chuar Group), Grand Canyon, Arizona. Journal of Paleontology 59:741–765.Google Scholar
Bloeser, B., Schopf, J. W., Horodyski, R. J., and Breed, W. J. 1977. Chitinozoans from the Late Precambrian Chuar Group of the Grand Canyon, Arizona. Science 195:676–679.CrossRefGoogle ScholarPubMed
Boeuf, O., and Gilbert, D. 1997. Presence de thécamoebiens du genre Trinema, au Pliocene supérieur, découverte a Chilhac (Haute-Loire, France). Comptes Rendus de l'Académie des Sciences, Série II, Sciences de la Terre et des Planets 325:623–627.Google Scholar
Bovee, E. C. 1985a. Class Lobosea Carpenter 1861. Pp. 158–211in Lee, et al. 1985.Google Scholar
Bovee, E. C. 1985b. Class Filosea Leidy, 1879. Pp. 228–245in Lee, et al. 1985.Google Scholar
Bradley, W. H. 1931. Origin and microfossils of the oil shale of the Green River Formation of Colorado and Utah. U.S. Geological Survey Professional Paper 168.CrossRefGoogle Scholar
Brasier, M. D., and Lindsay, J. F. 1998. A billion years of environmental stability and the emergence of eukaryotes; new data from northern Australia. Geology 26:555–558.2.3.CO;2>CrossRefGoogle ScholarPubMed
Brasier, M. D., McCarron, G., Tucker, R., Leather, J., Allen, P., and Shields, G. 2000. New U-Pb zircon dates for the Neoproterozoic Ghubrah glaciation and for the top of the Huqf Supergroup, Oman. Geology 28:175–178.2.0.CO;2>CrossRefGoogle Scholar
Brocks, J. J., Logan, G. A., Buick, R., and Summons, R. E. 1999. Archean molecular fossils and the early rise of eukaryotes. Science 285:1033–1036.CrossRefGoogle ScholarPubMed
Budin, K., and Philippe, H. 1998. New insights into the phylogeny of eukaryotes based on ciliate Hsp70 sequences. Molecular Biology and Evolution 15:943–956.CrossRefGoogle ScholarPubMed
Bui, E. T. N., Bradley, P. J., and Johnson, P. J. 1996. A common evolutionary origin for mitochondria and hydrogenosomes. Proceedings of the National Academy of Sciences USA 93:9651–9656.CrossRefGoogle ScholarPubMed
Butterfield, N. J. 2000. Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes. Paleobiology 26:386–404.2.0.CO;2>CrossRefGoogle Scholar
Butterfield, N. J., and Rainbird, R. H. 1998. Diverse organicwalled fossils, including ‘possible dinoflagellates’ from the early Neoproterozoic of arctic Canada. Geology 26:963–966.2.3.CO;2>CrossRefGoogle Scholar
Butterfield, N. J., Knoll, A. H., and Swett, K. 1990. A bangiophyte red alga from the Proterozoic of Arctic Canada. Science 250:104–107.CrossRefGoogle ScholarPubMed
Butterfield, N. J., Knoll, A. H., and Swett, K. 1994. Paleobiology of the Neoproterozoic Svanbergfjellet Formation, Spitsbergen. Fossils and Strata 34:1–84.CrossRefGoogle Scholar
Calver, C. R. 1998. Isotope stratigraphy of the Neoproterozoic Togari Group, Tasmania. Australian Journal of Earth Sciences 45:865–874.CrossRefGoogle Scholar
Canfield, D. E., and Raiswell, R. 1991. Pyrite formation and fossil preservation. In Taphonomy: releasing the data locked in the fossil record. Allison, P. A. and Briggs, D. E. G., eds. Topics in Geobiology 9:337–387. Plenum, New York.CrossRefGoogle Scholar
Cao, F., Duan, C., and Zhang, L. 1995. Discovery of Meishucunian vase-shaped microfossils in Ningqiang, Shaanxi and its significance. Geological Review 41:355–362, 2 plates.Google Scholar
Cavalier-Smith, T. 1993. Kingdom Protozoa and its 18 Phyla. Microbiological Reviews December:953–994.CrossRefGoogle Scholar
Cavalier-Smith, T., and Chao, E. E. 1996/7. Sarcomonad ribosomal RNA sequences, rhizopod phylogeny, and the origin of euglyphid amoebae. Archiv für Protistenkunde 147:227–236.CrossRefGoogle Scholar
Clark, C. G., and Roger, A. J. 1995. Direct evidence for secondary loss of mitochondria in Entamoeba histolytica. Proceedings of the National Academy of Sciences USA 92:6518–6521.CrossRefGoogle ScholarPubMed
Cook, D. A. 1991. Sedimentology and shale petrology of the Upper Proterozoic Walcott Member, Kwagunt Formation, Chuar Group, Grand Canyon, Arizona. . Northern Arizona University, Flagstaff.Google Scholar
Cushman, J. A. 1930. The Foraminifera of the Choctawhatchee Formation of Florida. Florida State Geological Survey Bulletin 4:1–63.Google Scholar
Dehler, C. M., and Elrick, M. E. 1998. Implications for paleoenvironments and areal extent of the Chuar basin from facies analyses of the middle Chuar Group (Neoproterozoic) Grand Canyon. Geological Society of America Abstracts with Programs (Rocky Mountain Section) 30(6):7.Google Scholar
Dehler, C. M., DesMarais, D. J., Bowring, S., Sharp, Z., Karlstrom, K. E., and Elrick, M. E. 1999. Chuar Group (1.1–0.74 Ga), Grand Canyon: carbon-isotope systematics at the onset of Sturtian glaciation. Geological Society of America Abstracts with Programs 31:A487.Google Scholar
Drouin, G., de Sá, M. Moniz, and Zuker, M. 1995. The Giardia lamblia actin gene and the phylogeny of eukaryotes. Journal of Molecular Evolution 41:841–849.CrossRefGoogle ScholarPubMed
Duan, C. 1985. The earliest Cambrian vase-shaped microfossils of Fangxian County, Hubei Province. Bulletin of the Tianjin Institute of Geology and Mineral Resources 13:87–107.Google Scholar
Duan, C., and Cao, F. 1989. A new discovery of Precambrian vase-shaped microfossils in the eastern Yangtze Gorges of Hubei Province. Bulletin of the Tianjin Institute of Geology and Mineral Resources 21:139–145, 2 plates.Google Scholar
Duan, C., Cao, F., and Zhang, L. 1993. Vase-shaped microfossils from top of the Tongying Formation in Xixiang, Shaanxi. Acta Micropaleontologica 10:397–408.Google Scholar
Ewetz, C. E. 1933. Einige neue Fossilfunde in der Visingsöformation. Geologiska Föreningens i Stockholm Förhandlingar 55:506–518.CrossRefGoogle Scholar
Fairchild, T. R., Barbour, A. P., and Haralyi, N. L. E. 1978. Microfossils in the ‘Eopaleozoic’ Jacadigo Group at Urucum, Mato Grosso, southwest Brazil. Boletim IG 9:74–79. Instituto de Geociências, Universidade de São Paulo, São Paulo.Google Scholar
Fauré-Fremiet, E. 1936. The Folliculinidae (Infusoria Heterotricha) of the Breton Coast. Biological Bulletin (Woods Hole) 70:353–360.CrossRefGoogle Scholar
Febvre-Chevalier, C. 1985. Class Heliozoea Haeckel 1866. Pp. 302–321in Lee, et al. 1985.Google Scholar
Felsenstein, J. 1978. Cases in which parsimony or compatibility methods will be positively misleading. Systematic Zoology 27:401–410.CrossRefGoogle Scholar
Ford, T. D. 1990. Grand Canyon Supergroup: Nankoweap Formation, Chuar Group, and Sixtymile Formation. Pp. 49–70in Beus, S. S. and Morales, M., eds. Grand Canyon geology. Oxford University Press, New York.Google Scholar
Ford, T. D., and Breed, W. J. 1969. Preliminary geologic report of the Chuar Group, Grand Canyon, Arizona. Pp. 114–122in Geology and natural history of the fifth field conference, Powell centennial river expedition, 1969. Four Corners Geological Society, Durango, Colo.Google Scholar
Ford, T. D., and Breed, W. J. 1973. Late Precambrian Chuar Group, Grand Canyon, Arizona. Geological Society of America Bulletin 84:1243–1260.2.0.CO;2>CrossRefGoogle Scholar
Frenguelli, G. 1933. Tecamebiani e Diatomee nel Miocene del Neuquen (Patagonia Settentrionale). Bollettino della Società Geologica Italiana 52:33–43.Google Scholar
Gajadhar, A. A., Marquardt, W. C., Hall, R., Gunderson, J., Ariztia-Carmona, E. V., and Sogin, M. L. 1991. Ribosomal RNA sequences of Sarcocystis muris, Theileria annulata and Cryptheconidium cohnii reveal evolutionary relationships among apicomplexans, dinoflagellates, and ciliates. Molecular Biochemistry and Parasitology 45:147–154.CrossRefGoogle ScholarPubMed
German, T. N. 1990. Organic world one billion year ago. Nauka, Leningrad.Google Scholar
Germot, A., Philippe, H., and Guyader, H. Le 1996. Presence of a mitochondrial-type 70-kDa heat shock protein in Trichomonas vaginalis suggests a very early mitochondrial endosymbiosis in eukaryotes. Proceedings of the National Academy of Sciences USA 93:14614–14617.CrossRefGoogle ScholarPubMed
Germot, A., Philippe, H., and Guyader, H. Le 1997. Evidence for loss of mitochondria in Microsporidia from a mitochondrial-type Hsp70 in Nosema locustae. Molecular Biochemistry and Parasitology 87:159–168.CrossRefGoogle ScholarPubMed
Gibbs, S. 1992. The evolution of algal chloroplasts. Pp. 107–121in Lewin, R.A., ed. Origins of plastids. Chapman and Hall, New York.CrossRefGoogle Scholar
Golemansky, V. 1974. Psammonobiotidae fam. nov.—une nouvelle famille de thécamoebiens (Rhizopoda, Testacea) du psammal supralittoral des mers. Acta Protozoologica 13:137–141.Google Scholar
Graham, L. E., and Wilcox, L. W. 2000. Algae. Prentice-Hall, Upper Saddle River, N.J.Google Scholar
Green, J. W., Knoll, A. H., and Swett, K. 1988. Microfossils from oolites and pisolites of the upper Proterozoic Eleonore Bay Group, Central East Greenland. Journal of Paleontology 62:835–852.CrossRefGoogle ScholarPubMed
Hamilton, J. M. 1952. Studies on loricate Ciliophora. I. Cothurnia variabilis Kellicott. Transactions of the American Microscopical Society 71:561–568.CrossRefGoogle Scholar
Han, T.-M., and Runnegar, B. 1992. Megascopic eukaryotic algae from the 2.1-billion-year-old Negaunee Iron-Formation, Michigan. Science 257:232–235.CrossRefGoogle ScholarPubMed
Hashimoto, T., Nakamura, Y., Kamaishi, T., and Hasegawa, M. 1997. Early evolution of eukaryotes inferred from protein phylogenies of translation elongation factors 1α and 2. Archiv für Protistenkunde 148:287–295.CrossRefGoogle Scholar
Hausmann, K., and Hülsmann, N. 1996. Protozoology, 2d ed.Thieme, Stuttgart.Google Scholar
Hibberd, D. J., and Leedale, G. F. 1985. Order 4. Chrysomonadida. Pp. 54–70in Lee, et al. 1985.Google Scholar
Hilario, E., and Gogarten, J. P. 1998. The prokaryote-to-eukaryote transition reflected in the evolution of the V/F/A-ATPase Catalytic and proteolipid subunits. Journal of Molecular Evolution 46:703–715.CrossRefGoogle Scholar
Hirt, R. P., Healy, B., Vossbrinck, C. R., Canning, E. U., and Embley, T. M. 1997. A mitochondrial Hsp70 orthologue in Vairomorpha necatrix: molecular evidence that microsporidia once contained mitochondria. Current Biology 7:995–998.CrossRefGoogle Scholar
Hoffman, P. H. 1987. Early Proterozoic foredeeps, foredeep magmatism, and Superior-type iron-formations of the Canadian Shield. Pp. 85–98in Kröner, A., ed. Proterozoic lithospheric evolution. American Geophysical Union, Washington, D.C.CrossRefGoogle Scholar
Hofmann, K. J. 1994. Proterozoic carbonaceous compressions (“metaphytes” and “worms”). In Bengtson, 1994.Google Scholar
Horodyski, R. J. 1987. A new occurrence of the vase-shaped fossil Melanocyrillium and new data on this relatively complex Late Precambrian fossil. Geological Society of America Abstracts with Programs 19:707.Google Scholar
Horodyski, R. J. 1993. Paleontology of Proterozoic shales and mudstones: examples from the Belt Supergroup, Chuar Group and Pahrump Group, western USA. In Nagy, B., Leventhal, J. S., and Grant, R. F., eds. Metalliferous black shales and related ore deposits. Precambrian Research 61:241–278.CrossRefGoogle Scholar
Horodyski, R. J., and Bloeser, B. 1983. Possible eukaryotic algal filaments from the Late Proterozoic Chuar Group, Grand Canyon, Arizona. Journal of Paleontology 57:321–326.Google Scholar
Kah, L. C., Sherman, A. G., Narbonne, G. M., Knoll, A. H., and Kaufman, A. J. 1999. δ13C stratigraphy of the Proterozoic Bylot Supergroup, Baffin Island, Canada: implications for regional lithostratigraphic correlations. Canadian Journal of Earth Sciences, 36:313–332.CrossRefGoogle Scholar
Karlstrom, K. E., Bowring, S. A., Dehler, C. M., Knoll, A. H., Porter, S. M., Marais, D. J. Des, Weil, A. B., Sharp, Z. D., Geissman, J. W., Elrick, M. B., Timmons, J. M., Crossey, L. J., and Davidek, K. L. 2000. Chuar Group of the Grand Canyon: record of breakup of Rodinia, associated change in the global carbon cycle, and ecosystem expansion by 740 Ma. Geology 28:619–622.2.0.CO;2>CrossRefGoogle ScholarPubMed
Kaufman, A. J., and Knoll, A. H. 1995. Neoproterozoic variations in the C-isotopic composition of seawater: stratigraphic and biogeochemical implications. Precambrian Research 73:27–49.CrossRefGoogle ScholarPubMed
Kaufman, A. J., Knoll, A. H., and Narbonne, G. M. 1997. Isotopes, ice ages, and terminal Proterozoic earth history. Proceedings of the National Academy of Sciences USA 94:6600–6605.CrossRefGoogle ScholarPubMed
Kennedy, M. J., Runnegar, B., Prave, A. R., Hoffmann, K.-H., and Arthur, M. A. 1998. Two or four Neoproterozoic glaciations? Geology 26:1059–1063.2.3.CO;2>CrossRefGoogle Scholar
Klenk, H.-P., Zillig, W., Lanzendörfer, M., Grampp, B., and Palm, P. 1995. Location of protist lineages in a phylogenetic tree inferred from sequences of DNA-dependent RNA polymerases. Archiv für Protistenkunde 145:221–230.CrossRefGoogle Scholar
Knoll, A. H. 1994. Proterozoic and Early Cambrian protists: evidence for accelerating evolutionary tempo. Proceedings of the National Academy of Sciences USA 91:6743–6750.CrossRefGoogle ScholarPubMed
Knoll, A. H. 2000. Learning to tell Neoproterozoic time. Precambrian Research 100:3–20.CrossRefGoogle ScholarPubMed
Knoll, A. H., and Bambach, R. K.In press. Directionality in the history of life: diffusion from a left wall or repeated scaling of the right? In Erwin, D. H. and Wing, S. L., eds. Deep time: Paleobiology's perspective. Paliobiology 26(Suppl. to No. 4) (in press).Google Scholar
Knoll, A. H., and Calder, S. 1983. Microbiotas of the late Precambrian Ryssö Formation, Nordaustlandet, Svalbard. Palaeontology 26:467–496.Google Scholar
Knoll, A. H., and Vidal, G. 1980. Late Proterozoic vase-shaped microfossils from the Visingsö Beds, Sweden. Geologiska Föreningens i Stockholm Förhandlingar 102:207–211.CrossRefGoogle Scholar
Knoll, A. H., Swett, K., and Burkhardt, E. 1989. Paleoenvironmental distribution of microfossils and stromatolites in the Upper Proterozoic Backlundtoppen Formation, Spitsbergen. Journal of Paleontology 63:129–145.CrossRefGoogle ScholarPubMed
Knoll, A. H., Swett, K., and Mark, J. 1991. Paleobiology of a Neoproterozoic tidal flat/lagoonal complex: the Draken Conglomerate Formation, Spitsbergen. Journal of Paleontology 65:531–570.CrossRefGoogle ScholarPubMed
Kraskov, L. N. 1985. Nakhodka problematichnikh organizmov v otlozheniykh chatkaragaikoii sviti (Talasskii khrebet). Pp. 149–52 in Obut, A. M. and Tchernysheva, N. J., eds. Problematitika pozdnego dokembriya i paleozoya.Google Scholar
Krumbein, W. E., Paterson, D. M., and Stal, L. J., eds. 1994. Biostabilization of sediments. Oldenburg University Press, Oldenburg, Germany.Google Scholar
Lee, J. J., Hutner, S. H., and Bovee, E. C., eds. 1985. An illustrated guide to the Protozoa. Society of Protozoologists, Lawrence, Kans.Google Scholar
Leedale, G. F. 1985. Order 3. Euglenida Bütschli, 1884. Pp. 41–54in Lee, et al. 1985.Google Scholar
Link, P. K., Christie-Blick, N., Devlin, W. J., Elston, D. P., Horodyski, R. J., Levy, M., Miller, J. M. G., Pearson, R. C., Prave, A., Stewart, J. H., Winston, D., Wright, L. A., Wrucke, C. T. 1993. Middle and Late Proterozoic stratified rocks of the western U.S. Cordillera, Colorado Plateau, and Basin and Range province. Pp. 463–595in Reed, J. C. Jr., Bickford, M. E., Houston, R. S., Link, P. K., Rankin, D. W., Sims, P. K., and Van Schmus, W. R., eds. The geology of North America. Geological Society of America, Boulder, Colo.Google Scholar
Loeblich, J.A.R., and Tappan, H. 1988. Foraminiferal genera and their classification. Van Nostrand Reinhold, New York.CrossRefGoogle Scholar
Maithy, P. K., and Babu, R. 1988. Chitinozoa-like remains from Vindhyan Supergroup of Son Valley. Palaeobotanist 37:77–80.Google Scholar
Maslov, A. V., Abduazimova, Z. M., Karsten, L. A., and Puchkov, V. N. 1994. Pervye nakhodki Mellanoserillium v etalonnykh rasresakh rifeya na Yuzhnon Urale. [First occurrence of Melanocyrillium in the Riphean type sections of the Southern Urals.] Pp. 90–91in Sostoyanie, problemy i zadachi geologicheskogo kartirovaniya oblastei rasvitiya dokembriya na territorii Rossi. [State, problems, and goals of the geological mapping of the Precambrian areas in Russia]. Vserossiiskii Geologicheskii Institut, St. Petersburg. [In Russian.]Google Scholar
Medioli, F. S., Scott, D. B., Collins, E. S., and McCarthy, F. M. G. 1990a. Fossil thecamoebians present status and prospects for the future. Pp. 813–839in Hemleben, C. et al., eds. Paleoecology, biostratigraphy, paleoceanography and taxonomy of agglutinated foraminifera. Kluwer Academic, Dordrecht, Netherlands.CrossRefGoogle Scholar
Medioli, F. S., Scott, D. B., Collins, E. S., and Wall, J. H. 1990b. Thecamoebians from the Early Cretaceous deposits of Ruby Creek, Alberta (Canada). Pp. 793–812in Hemleben, C., Kaminski, M. A., Kuhnt, W., and Scott, D. B., eds. Paleoecology, biostratigraphy, paleoceanography and taxonomy of agglutinated foraminifera. Kluwer Academic, Dordrecht, Netherlands.CrossRefGoogle Scholar
Medlin, L. K., Kooistra, W. H. C. F., Potter, D., Saunders, G. W., and Anderson, R. A. 1997. Phylogenetic relationships of the ‘golden algae’ (haptophytes, heterokont chromophytes) and their plastids. Plant Systematics and Evolution 11(Suppl.):187–219.CrossRefGoogle Scholar
Moldowan, J. M., Dahl, J., Jacobson, S. R., Huizinga, B. R., Fago, F. J., Shetty, R., Watt, D. S., Peters, K. E. 1996. Chemostratigraphic reconstruction of biofacies: molecular evidence linking cyst-forming dinoflagellates with pre-Triassic ancestors. Geology 24:159–162.2.3.CO;2>CrossRefGoogle Scholar
Nautiyal, A. C. 1978. Discovery of cyanophycean remains and chitinozoans from the late Precambrian argillaceous sequence of Satpuli, Garhwal Himalaya, India. Current Science 47:222–226.Google Scholar
Nystuen, J. P., and Siedlecka, A. 1988. The ‘Sparagmites’ of Norway. Pp. 237–252 in Winchester, J. A., ed. Late Proterozoic stratigraphy of the Atlantic regions. Blackie, Glasgow.CrossRefGoogle Scholar
Ogden, C. G. 1991. Ultrastructure of the vegetative organisation and initial stages of silica plate deposition in the soil testate amoeba Corythion dubium. Protoplasma 163:136–144.CrossRefGoogle Scholar
Ogden, C. G., and Hedley, R. H. 1980. An atlas of freshwater testate amoebae. British Museum (Natural History), London.CrossRefGoogle Scholar
Palacas, J. G., and Reynolds, M. R. 1989. Preliminary petroleum source rock assessment of Upper Proterozoic Chuar Group, Grand Canyon, Arizona. American Association of Petroleum Geologists Bulletin 73:397.Google Scholar
Patterson, D. J. 1994. Protozoa: Evolution and Systematics. Pp. 1–14in Hausmann, K. and Hülsmann, N., eds. Progress in protozoology. Proceedings of the IX international congress of protozoology, Berlin 1993. Gustav Fischer, New York.Google Scholar
Patterson, D. J. 1999. The diversity of eukaryotes. American Naturalist 154(Suppl.):S96–S124.CrossRefGoogle ScholarPubMed
Philippe, H., and Adoutte, A. 1995. How reliable is our current view of eukaryotic phylogeny? European Journal of Protistology 31:17–33.Google Scholar
Philippe, H., and Adoutte, A. 1998. The molecular phylogeny of eukaryota: solid facts and uncertainties. Pp. 25–56in Coombs, G. H., Vickerman, K. Frs, Sleigh, M. A., and Warren, A., eds. Evolutionary relationships among protozoa. Chapman and Hall, London.Google Scholar
Poinar, G. O. Jr., Waggoner, B. M., and Bauer, U.-C. 1993. Terrestrial soft-bodied protists and other microorganisms in Triassic amber. Science 259:222–224.CrossRefGoogle ScholarPubMed
Pratt, L. M., Summons, R. E., and Hieshima, G. B. 1991. Sterane and triterpane biomarkers in the Precambrian Nonesuch Formation, North American Midcontinent Rift. Geochimica et Cosmochimica Acta 55:911–916.CrossRefGoogle Scholar
Rainbird, R. H., Jefferson, C. W., and Young, G. M. 1996. The early Neoproterozoic sedimentary Succession B of northwestern Laurentia: correlations and paleogeographic significance. Geological Society of America Bulletin 108:454–470.2.3.CO;2>CrossRefGoogle Scholar
Reynolds, M. W., and Elston, D. P. 1986. Stratigraphy and sedimentation of part of the Proterozoic Chuar Group, Grand Canyon, Arizona. Geological Society of America Abstracts with Programs (Rocky Mountain Section) 18:405.Google Scholar
Roger, A. J., Svard, S. G., Tovar, J., Clark, C. G., Smith, M. W., Gillin, F. D., and Sogin, M. L. 1998. A mitochondrial-like chaperonin 60 gene in Giardia lamblia: evidence that diplomonads once harbored an endosymbiont related to the progenitor of mitochondria. Proceedings of the National Academy of Sciences USA 95:229–234.CrossRefGoogle Scholar
Saito, Y., Tiba, T., and Matsubara, S. 1988. Precambrian and Cambrian cherts in Northwestern Tasmania. Bulletin of the National Science Museum, Tokyo C 14:59–70.Google Scholar
Schopf, J. W. 1992. Evolution of the Proterozoic biosphere: benchmarks, tempo, and mode. Pp. 585–600in Schopf, J. W. and Klein, C., eds. The Proterozoic biosphere: a multidisciplinary study. Cambridge University Press, Cambridge.CrossRefGoogle Scholar
Schopf, J. W., Ford, T. D., and Breed, W. J. 1973. Microorganisms from the Late Precambrian of the Grand Canyon, Arizona. Science 179:1319–1321.CrossRefGoogle ScholarPubMed
Schuster, F. L. 1990. Phylum Rhizopoda. Pp. 3–18in Margulis, L., Corliss, J. O., Melkonian, M., Chapman, D. J., eds. Handbook of the Protoctista. Jones and Bartlett, Boston.Google Scholar
Semikhatov, M. A. 1991. General problems of Proterozoic stratigraphy in the USSR. Soviet Scientific Reviews, Section G, Geology Reviews 1:1–192.Google Scholar
Sergeev, V. N., Knoll, A. H., and Petrov, P. Yu. 1997. Paleobiology of the Mesoproterozoic-Neoproterozoic transition: the Sukhaya Tunguska Formation, Turukhansk Uplift, Siberia. Precambrian Research 85:201–229.CrossRefGoogle ScholarPubMed
Small, E. B., and Lynn, D. H. 1985. Phylum Ciliophora. Pp. 393–575in Lee, et al. 1985.Google Scholar
Sogin, M. L. 1991. Early evolution and the origin of eukaryotes. Current Opinion in Genetics and Development 1:457–463.CrossRefGoogle ScholarPubMed
Sogin, M. L. 1994. The origin of eukaryotes and evolution into major kingdoms. Pp. 181–192in Bengtson, 1994.Google Scholar
Sogin, M. L., Elwood, H. J., and Gunderson, J. H. 1986. Evolutionary diversity of eukaryotic small-subunit rRNA genes. Proceedings of the National Academy of Sciences USA 83:1383–1387.CrossRefGoogle ScholarPubMed
Sogin, M. L., Gunderson, J. H., Elwood, H. J., Alonso, R. A., and Peattie, D. A. 1989. Phylogenetic meaning of the kingdom concept: an unusual ribosomal RNA from Giardia lamblia. Science 243:75–77.CrossRefGoogle ScholarPubMed
Stiller, J. W., and Hall, B. D. 1997. The origin of red algae: implications for plastid evolution. Proceedings of the National Academy of Sciences USA 94:4520–4525.CrossRefGoogle ScholarPubMed
Stiller, J. W., and Hall, B. D. 1999. Long-branch attraction and the rDNA model of early eukaryotic evolution. Molecular Biology and Evolution 16:1270–1279.CrossRefGoogle ScholarPubMed
Stiller, J. W., Duffield, E. C. S., and Hall, B. D. 1998. Amitochondriate amoebae and the evolution of DNA-dependent RNA polymerase II. Proceedings of the National Academy of Sciences USA 95:11769–11774.CrossRefGoogle ScholarPubMed
Sudzuki, M. 1979. Marine Testacea of Japan. Sesoko Marine Science Laboratory Technical Report 6:51–61.Google Scholar
Summons, R. E., and Walter, M. R. 1990. Molecular fossils and microfossils of prokaryotes and protists from Proterozoic sediments. American Journal of Science 290-A:212–244.Google Scholar
Summons, R. E., Brassell, S. C., Eglinton, G., Evans, E., Horodyski, R. J., Robinson, N., and Ward, D. M. 1988. Distinctive hydrocarbon biomarkers from fossiliferous sediment of the Late Proterozoic Walcott Member, Chuar Group, Grand Canyon, Arizona. Geochimica et Cosmochimica Acta 52:2625–2637.CrossRefGoogle Scholar
Summons, R. E., Thomas, J., Maxwell, J. R., and Boreham, C. J. 1992. Secular and environmental constraints on the occurrence of dinosterane in sediments. Geochimica et Cosmochimica Acta 56:2437–2444.CrossRefGoogle Scholar
Tappan, H. 1980. Paleobiology of plant protists. W. H. Freeman, San Francisco.Google Scholar
Tappan, H. 1993. Tintinnids. Pp. 285–303in Lipps, J. H., ed. Fossil prokaryotes and protists. Blackwell Scientific, Boston.Google Scholar
Vasicek, M., and Ruzicka, B. 1957. Namurian Techamoebina from the Ostrava-Karvina coal district. Sbornik Naradniho Musea v Praze, Rada B, Prirodni Vedy. Acta Musei Nationalis Pragae, Series B, Historia Naturalis 13:333–340.Google Scholar
Venkatachala, B. S., and Kumar, A. 1998. Fossil microbiota from the Vaishnodevi Limestone, Himalayan Foothills, Jammu: age and palaeoenvironmental implications. Journal of the Geological Society of India 52:529–536.Google Scholar
Vidal, G. 1979. Acritarchs from the Upper Proterozoic and Lower Cambrian of East Greenland. Gr⊘nlands Geologiske Unders⊘gelse Bulletin 134:1–55.CrossRefGoogle Scholar
Vidal, G. 1994. Early Ecosystems: limitations imposed by the fossil record. Pp. 298–311in Bengtson, 1994.Google Scholar
Vidal, G., and Ford, T. D. 1985. Microbiotas from the Late Proterozoic Chuar Group (Northern Arizona) and Uinta Mountain Group (Utah) and their chronostratigraphic implications. Precambrian Research 28:349–389.CrossRefGoogle Scholar
Vidal, G., and Knoll, A. H. 1983. Proterozoic plankton. Geological Society of America Memoir 161:265–277.CrossRefGoogle Scholar
Vidal, G., and Moczydłowska, M. 1995. The Neoproterozoic of Baltica—stratigraphy, paleobiology and general geological evolution. Precambrian Research 73:197–216.CrossRefGoogle Scholar
Vidal, G., and Siedlecka, A. 1983. Planktonic, acid-resistant microfossils from the Upper Proterozoic strata of the Barents Sea Region of Varanger Peninsula, East Finnmark, Northern Norway. Norges Geologiske Unders⊘kelse 382:45–79.Google Scholar
Waggoner, B. M. 1996. Bacteria and protists from Middle Cretaceous amber of Ellsworth County, Kansas. PaleoBios 17:20–26.Google Scholar
Walcott, C. D. 1899. Precambrian fossiliferous formations. Geological Society of America Bulletin 10:199–244.CrossRefGoogle Scholar
Walter, M. R., Veevers, J. J., Calver, C. R., Gorgan, P., and Hill, A. C. 2000. Dating the 850–544 Ma Neoproterozoic interval by isotopes of strontium, carbon and sulfur in seawater, some interpretative models. Precambrian Research 100:371–433.CrossRefGoogle Scholar
Wolf, M. 1995. Verkieste Amöben in Steinkohlen aus dem Ruhrgebiet—erster Nachweis von Arcella Ehrenberg im Paläozoikum. Paläontologische Zeitschrift 69:1–6.CrossRefGoogle Scholar
Woods, K. N., Knoll, A. H., and German, T. N. 1998. Xanthophyte algae from the Mesoproterozoic/Neoproterozoic transition: confirmation and evolutionary implications. Geological Society of America Abstracts with Programs 30:A232.Google Scholar
Xiao, S., Knoll, A. H., Kaufman, A. J., Yin, L., and Zhang, Y. 1997. Neoproterozoic fossils in Mesoproterozoic rocks? Chemostratigraphic resolution of a biostratigraphic conundrum from the North China Platform. Precambrian Research 84:197–220.CrossRefGoogle Scholar
Yankaouskas, T. V., ed. 1989. Mikrofossilii dokembriia SSSR. Nauka, Leningrad.Google Scholar
Zhang, L. 1994. A new progress in research on vase-shaped microfossils from the Dengying Formation of Sinian in Southern Shaanxi Province. Acta Geologica Gansu 3:1–8.Google Scholar
Zhang, L., and Li, Y. 1991. The Late Sinian vasiform microfossils of Ningqiang, Shaanxi Province. Bulletin of the Xi'an Institute of Geological and Mineralogical Research, Chinese Academy of Geological Sciences 31:77–86.Google Scholar
Zhang, Z. 1986. Clastic facies microfossils from the Chuanlinggou Formation (1800 Ma) near Jixian, North China. Journal of Micropaleontology 5:9–16.Google Scholar