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Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: A classification guided by modern testate amoebae

  • Susannah M. Porter (a1), Ralf Meisterfeld (a2) and Andrew H. Knoll (a1)


Vase-shaped microfossil (VSM) assemblages from early diagenetic carbonate nodules in >742 ± 6 Ma black shales of the Chuar Group, Grand Canyon, provide evidence for affinities with testate amoebae. Not only are VSMs exceptionally preserved in Chuar rocks, they exhibit a much higher degree of morphological diversity than was previously known. Using the taxonomy of modern testate amoebae as a guide, nine new species and eight new genera of VSMs are described, augmenting the eight species and two genera already recognized. Taxa described here are Melanocyrillium hexodiadema Bloeser, 1985, Trigonocyrillium horodyskii (Bloeser, 1985) n. comb., T. fimbriatum (Bloeser, 1985) n. comb., Cycliocyrillium simplex n. sp., C. torquata n. sp., Bonniea dacruchares n. sp., B. pytinaia n. sp., Trachycyrillium pudens n. sp., Palaeoarcella athanata n. sp., Hemisphaeriella ornata n. sp., Bombycion micron n. sp., and Melicerion poikilon n. sp. All of the test characters observed in VSM taxa (e.g., collars; indentations; hexagonal symmetry; lobed, triangular or invaginated apertures; curved necks) occur in modern testate amoeban taxa, though not always in the same combinations. Some VSM species have characters found today in diverse extant taxa, making it difficult to assess their relationships. A few species, however, have character combinations that closely approximate those found in specific genera of both lobose and filose testate amoebae, suggesting that at least stem group, and possibly crown group, representatives of these taxa were present ∼742 Ma.

These fossils indicate that ecosystems were diverse and complex, that eukaryotic biomineralization had already evolved, and that the last common ancestor of animals+fungi had already appeared by ∼750 Ma.



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Allison, C. W., and Hilgert, J. W. 1986. Scale microfossils from the Early Cambrian of Northwest Canada. Journal of Paleontology, 60:9731015.
Baldauf, S. L., Roger, A. J., Wenk-Seifert, I., and Doolittle, W. F. 2000. A kingdom-level phylogeny of eukaryotes based on combined protein data. Science, 290:972977.
Bapteste, E., Brinkmann, H., Lee, J. A., Moore, D. V., Sensen, C. W., Gordon, P., Duruflé, L., Gaasterland, T., Lopez, P., Müller, M., and Philippe, H. 2002. The analysis of 100 genes supports the grouping of three highly divergent amoebae: Dictyostelium, Entamoeba, and Mastigamoeba . Proceedings of the National Academy of Sciences USA, 99:14141419.
Bhattacharya, D., Helmchen, T., and Melkonian, M. 1995. Molecular evolutionary analyses of nuclear-encoded SSU rRNA indentify an independent rhizopod lineage containing the Euglyphina and the Chlorarachniophyta. Journal of Eukaryotic Microbiology, 42:6569.
Binda, P. L., and Bokhari, M. M. 1980. Chitinozoanlike microfossils in a late Precambrian dolostone from Saudi Arabia. Geology, 8:7071.
Bloeser, B. 1979. Melanocyrillium—new acritarch genus from Kwagunt Formation (Late Precambrian) Chuar Group, Grand Canyon Supergroup, Arizona (abstract). American Association of Petroleum Geologists Bulletin, 63:420421.
Bloeser, B. 1980. Structurally complex microfossils from shales of the Late Precambrian Kwagunt Formation (Walcott Member, Chuar Group) of the eastern Grand Canyon, Arizona. Unpublished M.S. thesis, University of California, Los Angeles, 188 pp.
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, 59:741765.
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, 195:676679.
Bolivar, I., Fahrni, J. F., Smirnov, A., and Pawlowski, J. 2001. SSU rRNA-based phylogenetic position of the genera Amoeba and Chaos (Lobosea, Gymnamoebia): the origin of Gymnamoebae revisited. Molecular Biology and Evolution, 18:23062314.
Butterfield, N. J., Knoll, A. H., and Swett, K. 1994. Paleobiology of the Neoproterozoic Svanbergfjellet Formation, Spitsbergen. Fossils and Strata, 34:184.
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, 26:386404.
Cavalier-Smith, T. 1998. A revised six-kingdom system of life. Biological Reviews, 73:203266.
Cavalier-Smith, T., and Chao, E. E. 1996/7. Sarcomonad ribosomal RNA sequences, Rhizopod phylogeny, and the origin of euglyphid Amoebae. Archiv für Protistenkunde, 147:227236.
Charman, D. J. 1999. Testate amoebae and the fossil record: issues in biodiversity. Journal of Biogeography, 26:8996.
Clark, C., and Cross, G. 1988. Small-subunit ribosomal RNA sequence from Naegleria gruberi supports the polyphyletic origin of amoebas. Molecular Biology and Evolution, 5:512518.
Deflandre, G. 1928. Le genre Arcella Ehrenberg. Morphologie—Biologie. Essai phylogénétique et systématique. Archiv für Protistenkunde, 64:152287.
Deflandre, G. 1953. Ordres des Testacealobosa, Testaceafilosa, Thalamia, ou Thécamoebiens (Rhizopoda Testacea), pp. 97148. In Grassé, P.-P. (ed.), Traité de Zoologie. 1. Masson et Cie, Paris.
Dehler, C. M., Elrick, M. E., Karlstrom, K. E., Smith, G. A., Crossey, L. J., and Timmons, M. J. 2001. Neoproterozoic Chuar Group (∼800–742 Ma), Grand Canyon: a record of cyclic marine deposition during global climatic and tectonic transitions. Sedimentary Geology, 141–142:465499.
Ewetz, C. E. 1933. Einige neue Fossilfunde in der Visingsöformation. Geologiska Föreningens i Stockholm Förhandlingar, 55:506518.
German, T. N. 1990. Organic World One Billion Year Ago. Nauka, Leningrad.
Gnekow, M. A. 1981. Beobachtungen zur Biologie und Ultrastruktur der moosbewohnenden Thecamöbe Nebela tincta (Rhizopoda). Archiv für Protistenkunde, 124:3669.
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, 62:835852.
Hoogenraad, H. R., and Groot, A. A. D. 1941. Observations on a special manner of feeding of a species of Difflugia (D. rubescens Penard). Proceedings Nederlandse Akademie van Wetenschappen, 44:217228.
Horodyski, R. J. 1993. Paleontology of Proterozoic shales and mudstones: examples from the Belt Supergroup, Chuar Group and Pahrump Group, western USA. Precambrian Research, 61:241278.
Horodyski, R. J., and Mankiewicz, C. 1990. Possible Late Proterozoic skeletal algae from the Pahrump Group, Kingston Range, southeastern California. American Journal of Science, 290-A:149169.
Karlstrom, K. E., Bowring, S. A., Dehler, C. M., Knoll, A. H., Porter, S. M., Marais, D. J. D., 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, 28:619622.
Kaufman, A. J., Jacobsen, S. B., and Knoll, A. H. 1993. The Vendian record of Sr and C isotopic variations in seawater: implications for tectonics and paleoclimate. Earth and Planetary Science Letters, 120:409430.
Keeling, P. J. 2001. Foraminifera and Cercozoa are related in actin phylogeny: two orphans find a home? Molecular Biology and Evolution, 18:15511557.
Knoll, A. H. 1981. Paleoecology of Late Precambrian microbial assemblages, pp. 1754. In Niklas, K. J. (ed.), Paleobotany, Paleoecology and Evolution. Praeger Publishers, New York.
Knoll, A. H. 1996. Chapter 4: Archean and Proterozoic paleontology, pp. 5180. In Jansonius, J. and McGregor, D. C. (eds.), Palynology: Principles and Applications. 1. American Association of Stratigraphic Palynologists Foundation.
Knoll, A. H., and Calder, S. 1983. Microbiotas of the late Precambrian Ryssö Formation, Nordaustlandet, Svalbard. Palaeontology, 26:467496.
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, 63:129145.
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, 65:531570.
Knoll, A. H., and Vidal, G. 1980. Late Proterozoic vase-shaped microfossils from the Visingsö Beds, Sweden. Geologiska Föreningens i Stockholm Förhandlingar, 102:207211.
Kraskov, L. N. 1985. Nakhodka problematichnikh organizmov v otlozheniykh chatkaragaikoii sviti (Talasskii khrebet). Akademiya Nauk, SSSR, Sibirskoe otdelenie, Institut geologii i geofiziki, Trudy, 632:149152.
Kraskov, L. N. 1989. Microfossils of faunal origin, pp. 148151. In Yankaouskas, T. V. (ed.), Mikrofossilii dokembriia SSSR. Nauka, Leningrad.
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., and Wrucke, C. T. 1993. Middle and Late Proterozoic stratified rocks of the western U.S. Cordillera, Colorado Plateau, and Basin and Range province, pp. 463595. In Reed, J. C., 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. Volume C-2. Precambrian: Conterminous U.S. The Geological Society of America.
Mus, M. Martí 2001. Paleobiology and taphonomy of early problematic fossils. Unpublished Ph.D. dissertation, Uppsala University.
Mus, M. Martí, and Moczydłowska, M. 2000. Internal morphology and taphonomic history of the Neoproterozoic vase-shaped microfossils from the Visingsö Group, Sweden. Norsk Geologisk Tidsskrift, 80:213228.
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 [Supplement], 11:187219.
Meisterfeld, R. 2001. Testate amoebae, pp. 5457. In Costello, M. J., Emblow, C. S., and White, R. (eds.), European Register of Marine Species. A Checklist of Marine Species in Europe and a Bibliography of Guides to their Identification. Patrimoines naturels, 50.
Meisterfeld, R. 2002. Arcellinida, pp. 827860. In J. J. Lee and others (eds.), An Illustrated Guide to the Protozoa. Society of Protozoologists, Kansas.
Meisterfeld, R. 2002. Testate amoebae with filopodia, pp. 10541084. In J. J. Lee and others (eds.), An Illustrated Guide to the Protozoa. Society of Protozoologists, Kansas.
Mendelson, C. V. 1993. Acritarchs and prasinophytes, pp. 77104. In Lipps, J. H. (ed.), Fossil Prokaryotes and Protists. Blackwell Scientific Publications, Boston.
Moczydłowska, M. 1991. Acritarch biostratigraphy of the Lower Cambrian and the Precambrian-Cambrian bounday in southeastern Poland. Fossils and Strata, 29:127.
Ogden, C. G. 1983. Observations on the systematics of the genus Difflugia in Britain (Rhizopoda, Protozoa). Bulletin of the British Museum of Natural History (Zoology), 44:173.
Ogden, C. G., and Coûteaux, M. M. 1988. The effect of predation on the morphology of Tracheleuglypha dentata (Protozoa, Rhizopoda). Archiv für Protistenkunde, 136:107115.
Ogden, C. G., and Hedley, R. H. 1980. An Atlas of Freshwater Testate Amoebae. Oxford University Press, Oxford.
Ogden, C. G., and Meisterfeld, R. 1989. The taxonomy and systematics of some species of Cucurbitella, Difflugia and Netzelia (Protozoa: Rhizopoda); with an evalution of diagnostic characters. European Journal of Protistology, 25:109128.
Old, K. M. 1978. Fine structure of perforation of Cochliobolus sativus conidia by giant amoebae. Soil Biology and Biochemistry, 10:509516.
Patterson, D. J. 1994. Protozoa: evolution and systematics, pp. 114. In Hausmann, K. and Hülsmann, N. (eds.), Progress in Protozoology. Gustav Fischer, New York.
Patterson, D. J. 1999. The diversity of eukaryotes. American Naturalist, 154(Supplement):S96S124.
Philippe, H., and Adoutte, A. 1995. How reliable is our current view of eukaryotic phylogeny? European Journal of Protistology, 31:1733.
Porter, S. M., and Knoll, A. H. 2000. Testate amoebae in the Neoproterozoic Era: evidence from vase-shapes microfossils in the Chuar Group, Grand Canyon. Paleobiology, 26:360385.
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, 55:911916.
Saito, Y., Tiba, T., and Matsubara, S. 1988. Precambrian and Cambrian cherts in Northwestern Tasmania. Bulletion of the national Science Museum, Tokyo, Series C., 14:5970.
Schuster, F. L. 1990. Phylum Rhizopoda, pp. 318. In Margulis, L., Corliss, J. O., Melkonian, M., and Chapman, D. C. (eds.), Handbook of Protoctista. Jones and Bartlett Publishers, Boston.
Sims, G. P., Rogerson, A., and Aitken, R. 1999. Primary and secondary structure of the small-subunit ribosomal RNA of the naked, marine amoeba Vanella anglica: phylogenetic implications. Journal of Molecular Evolution, 48:740749.
Sogin, M. L., and Siberman, J. D. 1998. Evolution of the protists and protistan parasites from the perspective of molecular systematics. International Journal for Parasitology, 28:1120.
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, 52:26252637.
Tappan, H. 1993. Tintinnids, pp. 285303. In Lipps, J. H. (ed.), Fossil Prokaryotes and Protists. Blackwell Scientific Publications, Boston.
Verworn, M. 1888. Biologische Protistenstudien. Zeitschrift für wissenschaftliche Zoologie, 46:455470.
Vidal, G. 1979. Acritarchs from the Upper Proterozoic and Lower Cambrian of East Greenland. Bulletin—Gr⊘nlands Geologiske Undersogelse, 134:155.
Vidal, G. 1994. Early ecosystems: limitations imposed by the fossil record, pp. 298311. In Bengtson, S. (ed.), Early Life on Earth. Columbia University Press, New York.
Wanner, M. 1999. A review on the variability of testate amoebae: methodological approaches, environmental influences and taxonomic implications. Acta Protozoologica, 38:1529.
Wanner, M., and Meisterfeld, R. 1994. Effects of some environmental factors on the shell morphology of testate amoebae (Rhizopoda, Protozoa). European Journal of Protistology, 30:191195.
Woese, C. R., Kandler, O., and Wheelis, M. L. 1990. Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya. Proceedings of the National Academy of Sciences USA, 87:45764579.
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(7), A–232.
Wylezich, C., Meisterfeld, R., Meisterfeld, S., and Schlegel, M. 2002. Phylogenetic analyses of small subunit ribosomal RNA coding regions reveal a monophyletic lineage of euglyphid testate amoebae (Order Euglyphida). Journal of Eukaryotic Microbiology, 49:108118.

Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: A classification guided by modern testate amoebae

  • Susannah M. Porter (a1), Ralf Meisterfeld (a2) and Andrew H. Knoll (a1)


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